Assessment of the completion of the forest cadastre

UN-GGIM and its activities are base on national and regional activities structured with involvement of related organizations of its field for an in-depth discussion as well as activities from a profession. UN-GGIM is a representative and effective consultation mechanism striving to resolve globally challenging issues through utilization of the geospatial information and has a system that can implement directly to policies, factors relating to the global geospatial information with a professional knowledge basis. UN-GGIM pursuing factors are something that cannot be resolved in a short timeframe but through continuing efforts carried out on an extended term.


Introduction
The latest data covering the forest assets in Turkey was published in 2015. The area of the forest lands was stated to be 21,537,091 hectares in 2010. This figure was stated as 22,342,935 hectares in 2015 (TFA 2019). According to the forest cadastre works completed in 2017, the area of the forest lands was found to be about 24,000,000 hectares.
According to the General Directorate of Forestry (GDF) Strategic Plan 2010-2014, the ownership of 99% of the forests in Turkey belongs to the state. The forest lands, which cover 27.6% of the area of Turkey, have important economic, environmental, and cultural functions. About 10% of the population of Turkey lives in forest villages or the villages in the vicinity of the forests, where forest resources provide a vital contribution to the livelihood of the villagers. Urban dwellers have a growing interest in forests, particularly due to their biodiversity and environmental and social functions. (FAO 2015).
Within the framework of Goal 15 of the United Nations' 2030 Agenda for Sustainable Development Goals, several studies have been carried out to provide sufficient incentives for the protection, restoration, and promoting sustainable use of forests, sustainable management of all forest types, stopping deforestation, restoring degraded forests by rehabilitation by 2030. Moreover, the proposed solutions for the forestrelated issues were brought to the agenda of the international community.
The primary condition for the proper execution of the forest regime in line with modern forestry principles is the demarcation of the boundaries of the lands considered forests and their cadastre (Çağlar 2004). Forests are subject to registration in accordance with Article 11 of Forest Law No. 6831. The land is registered with the attribute of "forest" in the name of the Treasury. The registration can only be made after the completion of the forest cadastre. Forest cadastre covers the demarcation of the boundaries of the forests, the application works for the previous forest demarcation or cadastral operations following the new legislation, and registration of the lands whose boundaries are determined by the implementation of Article 2 of the Forest Law to the land registry system. The lands where the forest cadastre works and the application works were recently completed should be registered to the land registry system after solving the problems arising from the registration legislation of the General Directorate of Land Registry and Cadastre (GDLRC) and those arising from the private registered properties within the forest boundaries (GDF Strategic Plan 2013-2017).
In Turkey, the modern forest cadastre works started in 1937, when Forest Law No. 3116 entered into force. It was observed that forest demarcation and forest cadastre works were addressed in separate articles in the relevant Law. Article 10 of the Law stipulated that the forest demarcation works should be completed within five years. while Article 21 of the same Law stipulated that the cadastral works should be completed within 10 years. However, the forest cadastre works could not be completed until today due to various problems encountered in the implementation of this Law and its related regulations (Gençay 2012; GDF Strategic Plan 2010-2014).
The fact that the forest cadastre and ownership problems have not been resolved yet were based on the following reasons: property cadastre and forest cadastre works being carried out by different authorities (Ayanoğlu 1992; Anbar 2004; Gençay 2012); rural cadastre works being carried out faster than forest cadastre works due to these difficulties in forest demarcation (Ayanoğlu 1992); the relations between the administration and the local people negatively affected due to ownership disputes in many places; carrying out forestry activities in areas whose boundaries have not yet been demarcated; intensive political and social pressures; frequent amendments in legislation; insufficient number of staff; lack of expert staff; deficiencies in technology transfer and applications; that the economic, social, and educational status of the forest villagers are lower; that the forestry activities are open to nature; that the administration traditionally has centralized and instruction-oriented approaches; that the forest villagers constitute the economically poorest part of Turkey and they are generally forest-dependent for their livelihoods, etc. (GDF 2006).
On the other hand, the following solutions were proposed to ensure the protection and the safety of the forest assets: demarcation of the forests and registering them to the land registry system as soon as possible; facilitating the registration of the previous forest cadastre, which could not be registered to the land registry system, by cadastral renewal and update works ( The completion of the forest cadastre has become a corporate policy of the GDF. Also, this policy was included as a strategic goal in the annual reports and strategic plans of the institution. Annual Report 2011 states that it was aimed to complete the demarcation and cadastral procedures of all forest lands by the end of 2014, as well as, to complete the land registry procedures of the forest lands whose cadastre was completed and finalized. Moreover, it was stated that completing the forest cadastre procedures and registration of these lands to the land registry system was set as the ultimate goal in the Annual Report 2015 and Annual Report 2017 of the institution. On the other hand, in the GDF Strategic Plan 2010-2014, the goal was stated as completing the forest cadastre by the end of 2014. The issue was addressed in the GDF Strategic Plan 2010-2014 as the completion of the demarcation and cadastral procedures of the forest lands, as well as, the completion of the land registration procedures of the forest lands whose cadastre was completed and finalized. It was also In Turkey, the modern forest cadastre works started in 1937, when Forest Law No. 3116 entered into force. It was observed that forest demarcation and forest cadastre works were addressed in separate articles in the relevant Law. Article 10 of the Law stipulated that the forest demarcation works should be completed within five years. stated that significant legal and technical infrastructure works had been completed. The GDF Strategic Plan 2010-2014 stated the strategic goal as the complete elimination of the forest cadastre issue together with GDLRC by using state-ofthe-art technologies at the end of the plan period. Moreover, the establishment of a "Forest Cadastre Information System", where all digital and textual data about the permits granted for the lands considered forest and not forest were kept together, was also included in the goals of the GDF. In a study on the factors that delayed the forest cadastre works and the solution of forest cadastre issue, Gençay (2012) stated that lack of coordination between institutions, insufficient attention paid by the administration, shortage of trained personnel and equipment were the most significant factors among others. However, the most significant conclusion of this study was that the problem could be solved by facilitating the collaboration of the institutions.
The present study evaluates the organizational structures, legal infrastructures, the uses of technology of GDLRC and GDF in terms of collaboration within the scope of the solution of the forest cadastre issue, examines the solution methodology, reveals the results of the implementation of the method, offers suggestions for the joint projects between institutions.

Institutions and their duties The General Directorate of Forestry
The first initiatives in the forestry sector in Turkey started in 1839. In 1924, the Ministry of Agriculture was established and the GDF was affiliated. Forestry activities were carried out by GDF, which was affiliated with various ministries until today. GDF was affiliated with the Ministry of Agriculture and Forestry as per the Presidential Decree No. 4 dated 2018.
GDF carries out the forest cadastre activities through the Department of Forest Cadastre and Ownership. The major duties of the Department of Forest Cadastre and Ownership can be listed as follows: performing forest cadastre procedures; carrying out works and procedures regarding the determination and evaluation of the areas taken out of forest boundaries; settlement of various disputes regarding state forests; carrying out works and procedures regarding the inspection and control of forests belonging to parties other than the state; carrying out works for granting permission, usufruct, and easement for forest areas; following up and finalizing the land registry procedures of the lands for which the forest cadastre works are completed, etc.

General Directorate of Land Registry and Cadastre
The First Land Registry Organization was established in 1847, and it served under various names until 1923 when the Turkish Republic was declared. In 1924, the "General Directorate of Land Registry" was established, and the cadastre branch was added in 1925. GDLRC, which attained its current organizational structure i. Carrying out cadastre procedures in Turkey and to follow up the changes, ii. Ensuring renewal and updating of the cadastre plans and performing the related control and auditing services; iii. Ensuring the reliability of land registries, which is under the responsibility of the state, regularly, iv. Performing all kinds of contractual and non-contractual registration transactions related to real estates, v. Following up and controlling the changes on the registers, vi. Ensuring the protection of records and documents by archiving, vii. Establishing a geodetic network, spatial information system infrastructure, and map production monitoring centre for the production of large-scale cadastral and topographic maps.

Laws and regulations on forestry Laws and regulations on the Forestry Procedures
Land Law dated 1858, which was the first regulation on forests, stated that forests were public property and could not be subject to private property. On the other hand, Article 24 of the Forest Regulations dated 1870 prohibited the acquisition of the state-owned forests and forests specific to villages and towns through prescription.
The regulations on the forests are inspired by the principles of protection of forests and ensuring their sustainability, governance, and execution of the forest regime by the State, and demarcation of the forest boundaries within this framework. During the Republic period, forestry regulations were made after the Civil Code, which entered into force in 1926. The first comprehensive regulation on forestry was Forest Law No. 3116 dated 1937. This Law aimed to demarcate the boundaries of the State forests, to survey the forest lands and register them to the land registry system, and to complete these procedures within 5 years. has not been started, the cadastral team shall carry out the forest cadastre and determine the common boundaries of all kinds of real estates in these forests and adjacent to these forests and finalize them. ii. In these works, at least one forest engineer to be assigned by the provincial organization of the GDF and an agricultural engineer to be assigned by the Agricultural Directorates shall participate in the cadastral team within seven days from the notification. iii. In case the village head (mukhtar) and expert witness do not participate in these works, the works shall be continued ex officio, iv. In the examination of the objections made about the forest, a forest engineer to be assigned by the provincial organization of the GDF and an agricultural engineer to be assigned by the Agricultural Directorate, who have not taken part in the finalization work subject to objection, shall participate in the cadastral commission, v. The demarcation of the forests in the cadastre project area and their finalization shall be made by this team, and it shall be partly announced for thirty days. vi. The forest cadastre in these places shall be deemed to have been made, and these boundaries shall be followed exactly where the forest cadastre is finalized.
The additional Article 5 added to the Cadastre Law No. 3402 in 2013 stipulated that the forests that were not demarcated or did not undergo forest cadastre within the project areas where cadastre or rural cadastre works were completed should be subject to cadastre within the framework of the principles stated in Articles 4 and 39.
The following provisions were introduced with the paragraphs added to Article 4 of the Cadastral Law No. 3402 in 2018: i. In case of detection of incompatibility between records, sheet, and ground requiring correction in forest maps that are finalized after forest demarcation or cadastre, regardless of whether it is registered to the land registry system or not, the cadastre team to be formed with the participation of at least one forest engineer to be assigned by the related forestry directorate and a control engineer or engineer to be assigned by the cadastre directorate as per Article 3 of this Law shall apply the boundary points and lines of the forest to the ground based on the forest cadastre records, ii. The detected incompatibility shall be corrected following the technical regulations by the abovementioned cadastral team organized; at the end of the work, a report shall be prepared, and this report shall be signed together by the team members and the forest and cadastre engineers. iii. The correction procedure shall be finalized following the announcement to be made as per Article 11 of this Law, iv. Provided that GDLRC obtain the approval of the Ministry with which it is affiliated and the costs of such works are paid by GDF to the account of GDLRC Revolving Fund, GDLRC may also have some or all of the technical parts of such works done by natural or legal persons by way of tenders, and these tenders shall allow making commitments for the next years.
As per Law No. 6831, theodolites were started to be used in the forest cadastre works after 1960 (Tüdeş T & Bıyık C 1997). In the survey method, the starting point was selected from certain points; however, the sequential boundaries of the forests, instead of the district boundaries, were taken this time. To complete the surveying of the boundaries of the forest more quickly, the angles were measured using a theodolite in grades, and distances were measured using a levelling rod in the traverse surveying according to those days' technology. The polygonal chains obtained were not connected to the national triangulation network. A specific point of the village or town, such as a mosque or a school, was taken as a reference, and the boundaries were ditched in the field; however, they disappeared over time. The collapse or displacement of buildings, which were deemed fixed and stationary points, did not often allow the demarcation map correctly to the ground (Ayanaoğlu 1992). This method was abandoned after using aerial photographs in mapping.
Then, the Photogrammetry Method, which is defined as "Photo interpretation and manual marking of forest lands into aerial photographs with 60% overlapping under stereoscopic view", was used. The aerial photographs marked in this way were evaluated using photogrammetry devices and transferred to 10K-scale maps obtained from 25K-scale standard topographic maps by using photomechanical methods. Later, this method, which aimed to demarcate the boundaries of forests quickly, brought about the issue of producing maps without technical quality.
The above-mentioned method was also used in the "Forest Cadastre" works within the scope of Law No. 1744. In addition to this method, the forest cadastre works were carried out using the images of 5K-scale Standard Topographic Maps and Standard Topographic Cadastral Maps showing integrity with the land in places where these maps were already produced. Also, the forest cadastre works were carried out by marking the parcels surveyed using the terrestrial surveying method on 10K-and 5K-scale maps.
All of the above-mentioned methods were abandoned as of 1983. Moreover, the principle of performing forest cadastre works using the terrestrial surveying method has been adopted since then. In case the forest cadastre or forest demarcation was to be re-marked (application) on the ground, it was suggested as the main principle that the work would be renewed by using the same technique and tools that had been used in the previous work.

Solution methodology
Collaboration GDLRC has started the initial cadastre works in 1925, and GDF has started the forest cadastre works in 1934. However, the performance of the cadastre works by two institutions has brought about several problems since then.
Several problems were faced in the registration of the forest maps produced by the Forest Cadastre Commissions since they did not employ a survey engineer and these maps did not comply with the technical standards. Therefore, some of the forest cadastre works could not be registered by GDLRC. Another problem was that the technical errors could not be corrected by GDF without a judicial decision (as well as the lack of a legal regulation on this issue).
Another issue was that the number and the organization of the teams and the cadastral activities (initial cadastre and forest cadastre activities) of both institutions were different. Therefore, the works could not be carried out synchronously, which caused duplications.
Two actions were taken to eliminate these problems. Firstly, employing a survey engineer to the forest cadastre commissions was decided to eliminate the technical errors in the forest maps under the responsibility of the survey engineer. However, the number of forest cadastre commissions was another issue even they were supported by employing a survey engineer. Therefore, the second effective formula was decided to increase the number of forest cadastre commissions to facilitate completing the forest cadastre works throughout the country. The best formula to solve this problem was the combination of the resources of GDF, as an expert institution in forestry, and GDLRC, as an expert institution in mapping. It was concluded that the collaboration environment should be provided for both institutions to carry out this work together.
Thus, carrying out the works with an understanding of 'collaboration' by mutual transfer of resources and staff (assignment) was decided to be an effective solution. i. "In case of detection of incompatibility between records, sheet, and ground requiring correction in forest maps that are finalized after forest demarcation or cadastre, regardless of whether it is registered to the land registry system or not, the cadastre team to be formed with the participation of at least one forest engineer to be assigned by the related forestry directorate and a control engineer or engineer to be assigned by the cadastre directorate following Article 3 of this Law shall apply the boundary points and lines of the forest to the ground based on forest cadastre records, ii. The detected incompatibility shall be corrected following the technical regulations by the above-mentioned cadastre team to be organized; at the end of the work, a report shall be prepared, and this report shall be signed together by the team members and the forest and cadastre engineers. The correction procedure shall be finalized following the announcement to be made as per Article 11 of this Law, iii. Provided that GDLRC obtain the approval of the Ministry with which it is affiliated and the costs of such works are paid by GDF to the account of GDLRC Revolving Fund, GDLRC may also have some or all of the technical parts of such works done by natural or legal persons by way of tenders, and these tenders shall allow making commitments for the next years.
Thus, the technical errors in forest maps could be corrected by the forest cadastre commissions, as well as, by the cadastre team to be formed by GDLRC with the participation of a forest engineer from the GDF and a control engineer from the cadastre directorate.
An additional paragraph was added to Article 10 of Law No. 6831 as per Article 13 of Law No. 6292 dated 19.04.2012. This additional paragraph states that "Surveying, calculation, drawing, and survey applications for the preparation of maps of forests whose cadastre works are completed or ongoing shall be carried out by survey and cadastre engineers or technicians; the responsibility shall belong to the survey and cadastral engineers; a control engineer shall be assigned by the provincial directorate of GDLRC to ensure that the surveying and mapping procedures conducted in the field are carried out duly and to control and approve these works; the maps, which are produced following the cadastral technical standards, shall be approved by the head of the commission after the control approval of the survey and cadastre engineers".
Moreover, an additional paragraph was added to Article 10 of Law No. 6831 as per Article 13 of Law No. 6292. This additional paragraph stipulated that "Surveying, calculation, drawing, and application works for the preparation of maps of forests whose cadastre works are completed or ongoing shall be carried out by survey and cadastre engineers or technicians; the responsibility shall belong to the survey and cadastre engineers; a control engineer shall be assigned by the local directorate of GDLRC to ensure that the surveying and mapping procedures conducted in the field are carried out duly and to control and approve these works; the maps, which are produced following the cadastral technical standards, shall be approved by the head of the commission after the control approval of the survey and cadastre engineers".
Collaboration between the two institutions can be achieved in two ways. In the first option, in case the technical errors in forest maps are corrected by forest cadastre commissions, a control engineer from GDLRC may involve in the correction procedure. In the second option, in the forest cadastre works to be carried out by forest cadastre commissions, the surveying, calculation, drawing, and application work for the preparation of forest maps are carried out by the survey engineers or technicians to be assigned by the related cadastre directorate.
GDLRC has been carrying out forest cadastre during the initial cadastre works since 2005 (Article 4 of Law No. 3402).
Moreover, GDLRC has been carrying out forest cadastre for the forest lands that were not finalized during the initial cadastre works completed in the villages or quarters since 2013 (Additional Article 5 of Law No. 3402). In these works, a forest engineer from GDF and an agricultural engineer from the agricultural directorate participated in the cadastre team.

Use of technology
The amendments made to the laws in 2004 and 2005 introduced radical changes in both forest cadastre and general cadastral activities carried out by GDLRC. With these changes, the task of demarcating the forest boundaries in places that did not undergo cadastre was assigned to the GDLRC cadastre teams. It was stipulated that at least one forest engineer from the GDF and an agricultural engineer from the agricultural directorate should be assigned to these teams. Thus, GDF personnel participated in the cadastral works carried out by GDLRC in 3,000 villages since 2006 as per Law No. 3402.

GDF established GPS Teams in 8 Regional
Directorates of Forestry for supporting all Forest Cadastre Commissions, densification of the triangulation network, and digitization of forest cadastral maps. Also, a control system based on a database was developed and put into practice. Moreover, a geographic information system-based map server was also put into service for the first time on a portal on the official website of GDF. Technical On the other hand, GDLRC used the Regulation on the Production of Large-Scale Maps and the circulars published by the institution on the GNSS (Global Navigation Satellite System) surveying, calculation, and control, which are not addressed in the regulation.
With the widespread use of the CORS-TR (Continuously Operating Reference Stations) project, both institutions began to use it in 2009. Since CORS-TR has become the national fundamental infrastructure in geospatial projects, it has been widely used by all institutions and organizations. Also, geographical information systems applications have been widely used for creating the spatial data infrastructure in both institutions.
With these technological developments, both GDLRC and GDF began to produce and share digital geospatial data.

Results
Several significant factors caused the problems experienced for years in forest cadastre. The first factor was that the cadastre was classified as forest cadastre The amendments made to the laws in 2004 and 2005 introduced radical changes in both forest cadastre and general cadastral activities carried out by GDLRC.
With these changes, the task of demarcating the forest boundaries in places that did not undergo cadastre was assigned to the GDLRC cadastre teams. It was stipulated that at least one forest engineer from the GDF and an agricultural engineer from the agricultural directorate should be assigned to these teams. and property cadastre, and they were carried out by different institutions. The second factor was the technologies used in the cadastre works; although they were widely used in those days, they were obsolete today. Another factor was the complex structure of regulations due to frequent amendments due to needs.
The solution to the problem was achieved by giving priority to the completion of the property cadastre for meeting the investment priorities for the development of the country and the evolving needs with the conditions of the day, as well as, to solve the ongoing problems about forest lands and other property problems that arose in the following years due to these problems ( The collaboration between institutions was achieved based on the idea to eventually register the forest cadastre, and the required regulation amendments were made. Within the scope of the solution methodology, the approach of the participation of the private sector in forest cadastre works was adopted for digital and quick cadastre.
Therefore, the technical parts of the cadastre works were given out by contracts to the private sector by GDLRC under the coordination of both institutions. This outsourcing approach accelerated the projects through the use of modern technology. Collaboration was achieved between the two institutions engaged in property cadastre and forest cadastre by establishing legal and technical infrastructures within the framework of the definition of Cadastre.
Thanks to the participation of the private sector, the forest cadastre was completed in digital format and in a very short time between 2010 and 2017 at the end of the project. Moreover, the registration of 82.52% of these lands was completed. Effective and efficient use of public resources has been through collaboration. However, a major social problem was solved by making cadastre of the areas taken out from the forest and these parcels were sold to the users.
In addition to these achievements, a model compatible with the UN Agenda 2030, Digital Transformation, Sustainable

Conflicts of interest
The authors declare no conflicts of interest.  The land plots and building lines from the orthomosaic were obtained by two different techniques; which are manual digitization and automated feature extraction technique using MRS, while the ground survey parcel data was used as reference. Also, the manually digitized property boundary features were used as reference information for the automatically extracted features. Figure 3 depicts the AutoCAD drawing obtained from ground survey approach which was used as reference data for the UAV survey data.

Results and discussion
Other results obtained are the result of the accuracy evaluation of the automatically extracted visible boundaries using the MRS algorithm at different SPs (see Tab. 4 and Tab. 5), and the result of the cost and time comparison of the UAV and GNSS survey (see Tab. 6 and Tab. 7).

Scale Parameters of MRS
The results obtained when the SP of the MRS was set at 150, 400 and 500 are shown in Figure 4a - Figure 4c with the blue line depicting the boundary lines of every segment. It was observed that the output polygon continues to decrease with an increase in the value of the SP. Also, the visual clarity of the output polygon improves with increase in the value of the SP. When compared to the output of the automatically extracted visible boundaries using MRS with SP values 150 and 400 ( Fig. 4a and Fig. 4b), the pixel level in the output map was observed to be decreasing continuously with increase in SPs as observed in the result obtained when the SP value was set at 500 (Fig. 4c). Figure 5 presents the automatically extracted visible boundaries when the SP value of the MRS was set at 700, while Figure 6 presents the segmentation result obtained when the SP was fixed at 1000. Analysis of these two results showed that the pixel level decreased with increased value of SP. The output map of SP = 1000 gives a more cartographically appealing result based on its stronger pixel level. The yellow line in Figure 5 shows the boundary lines of every segment when SP = 700 was used while the red line in Figure 6 shows the boundary lines of every segment when SP = 1000 was used.
Accuracy assessment for the generated orthomosaic and automatic feature extraction Table 2 presents the planimetric coordinates and discrepancy between the GNSS acquired coordinates and the extracted coordinates of the CPs from the UAV generated orthomosaic. From Table 2, ΔN (m) and ΔE (m) represents the difference in planimetric (northing and easting) coordinates as obtained from GNSS acquired data and UAV generated orthomosaic.
The obtained horizontal RMSE (RMSEx, y) as computed using equation (7) is 0.3575. This is consistent with the result obtained by Karabin et al. (2021) and it affirms the applicability of UAV in cadastral or property mapping.
The result of the estimated completeness, correctness and overall accuracy of the automatically extracted building footprints at different SPs is presented in Table 3, while the results obtained from the estimated completeness, correctness and overall accuracy of the automatically extracted land parcels at different SPs is presented in Table 4.
The result (see Tab. 3) shows that a completeness, correctness and overall accuracy of 16%, 12% and 14%, respectively, was obtained when the MRS algorithm was deployed for the automatic extraction of the building lines or footprints at a SP = 150. When the SP was set at 700, 89% and 91% completeness and correctness, respectively were obtained with overall accuracy of 86% while an overall accuracy of 88% was obtained when the SP was set at 1000 with 92% and 95% completeness and correctness, respectively. Meanwhile, a completeness, correctness and overall accuracy of 25%, 18% and 19% was obtained when the SP was prefixed at 150 for the automatic extraction of land parcels (see Tab. 4), while 65%, 59% and 54% were obtained for the completeness, correctness and overall accuracy, respectively, when the SP was set at 1000 for the automatic extraction of the land parcels using the MRS algorithm. The poor completeness, correctness and overall accuracy obtained from the automatically extracted land parcels when compared to the result of the building footprints can be attributed to the presence of shadows, unclear delineation of the boundary lines of the land parcels in vegetated areas, and the presence of mixed pixels in the automatic extraction (Horkaew et al., 2015; Wassie, 2016). The findings show that increase in the SP of the MRS algorithm also leads to increase in the obtained completeness, correctness and overall accuracy for the extraction of the building footprints and the land parcels. Also, it was observed that optimal completeness, correctness and overall accuracy of the automatic feature extraction was obtained when the SP is set at 1000, while setting the SP at 150 will not yield a reliable result. The result of the accuracy assessment is consistent with the findings of

Cost and time comparison
The results obtained from the time and cost analysis of the integrated UAV-photogrammetry approach and the GNSS survey methods used for the survey of 248 land parcels are presented in Table 5 and Table 6, respectively. From the results presented in Table 5 and Table 6, it can be observed that the parcel boundary extracted using GNSS method requires more intense field observation, thus, it consumes more time and cost. However, cadastral boundary extractions from UAV generated orthomosaic involves less field work and more off-field processing, and it is also more economical when compared to the GNSS method. Based on the time analysis, it was observed that the total time taken to map the 248 properties using the UAV photogrammetry approach was just about one-third (1/3) of the total time expended when GNSS method was adopted. While the project was executed within just 12 days using the UAV approach, it took a total of 30 days for the project to be completed using the conventional GNSS approach which shows that the integrated UAV approach is 2.5 times faster than the conventional GNSS approach, even when the same manpower was deployed for the project.
It was also observed that the cadastral boundary obtained using GNSS method requires more personnel, equipment and resources for detail field observation and data processing. However, less human effort with very few equipment is required for UAV data capturing and image processing, and also in vectorizing the UAV generated orthomosaic, which is also consistent with the findings of Karabin et al. (2021). The results obtained from the cost comparison of these two approaches as presented in Table 6 shows that a total amount of N1 190 000.00 was expended for the mapping of 248 land parcels at the cost of less than N5 000.00 per parcel when the UAV approach integrated with the automatic feature extraction was used, while an approximate cost of N11 160 000.00 was expended when GNSS approach was used to survey the same 248 land parcels at an average cost of N45 000.00 per parcel. This implies that for large scale property mapping, the presented UAV approach integrated with automatic feature extraction is approximately nine (9) times cheaper or less expensive than the classical GNSS surveying approach without compromising the obtainable accuracy.

Conclusions
The principal objective of this research is to investigate the applicability of UAV photogrammetry integrated with automatic feature extraction for cadastral mapping. MRS algorithm with different SP was implemented for the automatic extraction of visible cadastral boundaries defined by linear features such as defined nodes and building footprints. The result obtained from the automatic feature extraction shows that the accuracy of the cadastral boundary line extraction depends majorly on the SP which is the key control of the MRS algorithm. For the experiments conducted using varying SPs and constant shape and compactness value, the result obtained shows that the pixel level in the output map decreases continuously with increase in SPs while the optimal result of the conducted experiment was obtained when the SP was set at 1000, while the shape and compactness values were set at 1.5 m and 0.8 m, respectively. The result of the evaluation of the reliability of the automatic extraction also shows that the completeness, correctness and overall accuracy or quality increases with increase in the value of the SPs. Also, the MRS algorithms proved to be more efficient in automatically extracting building footprints when compared to its performance in the extraction of land parcels.
Furthermore, the results of the accuracy assessment obtained from the integrated UAV approach when compared with conventional survey approach shows that 99% of automatically extracted property boundaries from the UAV survey falls within the minimum acceptable horizontal accuracy for cadastral and property mapping of third order (1: 5,000). Further analysis on the cost and time expended for the property mapping using the integrated approach shows that the approach is approximately 2.5 times faster and 9 times cheaper than the conventional ground surveying approach, especially when GNSS receivers are used for the spatial data acquisition. While

Data availability statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.

Abstract
Animals use the geomagnetic field and astronomical cues to obtain compass information. The magnetic compass is not a uniform mechanism, as several functional modes have been described in different animal groups. The Sun compass requires the internal clock to interpret the position of the Sun. For star compass orientation, night migrating birds seem to use the star pattern as a whole, without involving the internal clock. Both the astronomical compass mechanisms are based on learning processes to adapt them to the geographic latitude where the animals live and, in long living animals, to compensate for the seasonal changes. Several mechanisms are used to determine the compass course to a goal. Using information collected during the outward journey is mostly done by path integration: recording the direction with a compass and integrating its twists and turns. Migratory animals have innate programs to guide them to their still unknown goal. Highly mobile animals with large ranges develop a so-called navigational 'map', a mental representation of the spatial distribution of navigational factors within their home region and their migration route. The nature of the factors involved is not yet entirely clear; magnetic intensity and inclination are the ones best supported so far.

Introduction
Many animals perform extended migrations. Most famous are the annual migrations of millions of birds that, in autumn, leave regions with adverse winter conditions to overwinter in more favorable parts of the Earth. The record holder in distance is the Arctic tern, Sterna paradisea, a sea bird breeding in the Arctic regions that spends the winters at the edge of the Antarctic Continent, thus staying in eternal summer, avoiding coldness and darkness. But many other birds migrate as well, covering several thousand kilometers every year; among them are, e.g., water birds, raptors, swifts and small songbirds such as swallows, warbler and others. They spend the summer in the northern temperate zones and move to lower latitudes, some of them crossing the equator for wintering. Whales cover long distances between their Arctic or Antarctic feeding grounds and areas with warmer water where they give birth to their calves. But also terrestrial mammals, like many hoofed animals, perform long distance migrations to follow the annual change in vegetation, e.g., the caribous in northern Canada or zebras, gnus and antelopes in eastern Africa. Some animals migrate between nesting and feeding grounds, e.g., marine turtles. Many fishes migrate; some of them, like eels and salmons, only at the beginning and end of their life. Even some insects migrate: the monarch butterfly, Danaus plexipus, is a prominent example.
Most of these migrations involve specific routes and defined end points. Eels and salmons, as well as marine turtles are known to leave their feeding sites after years to return to the places where they were born to lay their eggs. Banded birds were found to return to the same breeding site year after year, and many of them seem to spend the non-breeding season in the same wintering grounds every year.
Birds are also known to return after passive displacement from unfamiliar sites. Homing pigeons, Columba livia domestica, bred from the Mediterranean rock dove, were domesticated and used to transport messages already since antiquity. But other bird species, too, were found to be able to compensate for displacements; that is, they can directly head toward a specific goal. The same appears to be true for numerous other animals, with the distances involved correlated with the size of their home range.
Yet, the ability to navigate is not only required for extended migrations and displacements like those mentioned above, but also during their everyday movements within their home range animals profit greatly from good orientation, because it is advantageous to optimize routes-this saves energy and helps to avoid predation.
To answer the question what factors animals use to navigate, it is important to understand how they proceed when they want to reach a specific goal. Birds are by far the best studied grouphoming pigeons are available ad libitum and can be easily used for orientation experiments. When they are released at a distant site, they leave this site heading in directions close to the home direction.
With migratory birds, their innate tendency to seasonally move in their migratory directions provides a reliable, solid baseline for cage experiments.
Hence much of our present knowledge on animal navigation comes from studies with birds, but many of the processes and procedures identified in birds seem to have parallels in other animals.

The "Map-and-Compass" model
Systematic research on animal navigation began in the second half of the twentieth century, when Gustav Kramer [1] and Karl von Frisch [2] in 1950 reported that birds and bees can use the Sun for orientation. The Sun compass, thus, was the first orientation mechanism described (see below). In the course of his experiments with homing pigeons, Kramer recognized that avian navigation is a two step process and proposed his Map-and-Compass model (e.g., [3]): When birds intend to return home from a distant site, they first determine the compass course leading to the goal and then use a compass to look up this direction and follow it home. Thus the first step of navigation, the Map step means applying mechanisms for determining the present position and put it in directional relation to the goal, and the second step, the Compass step, means applying mechanisms which allow to locate specific directions.
The Map-and-Compass model was first developed to describe the homing process of pigeons after displacement, with the Sun compass for the compass step, while the mechanisms by which the pigeons determine their home course could not yet be identified. This model, however, can be expanded to characterize avian navigation in general.
In the beginning, young birds use information obtained during the outward journey, and for the first migration to the still unknown wintering area, the map step is replaced by a genetic program that makes birds move into an innate direction for a certain time.
Experienced birds, however, are then able to truly navigate, using local site specific information, within and beyond their home region as well as during migration (for review, see, e.g., [4]).
Little is known about the navigation procedures of other animals, but we tend to assume that in many cases they might proceed in a similar way when they have to reach a specific goal. However, in some cases under certain conditions, they might use more direct mechanisms.
When Kramer [3] proclaimed the Mapand-Compass model, the Sun compass was the only navigational mechanism yet known. Research during the last decades increased our knowledge on the factors and mechanisms of animal navigation considerably, even if many questions are still open. In particular, the compass mechanisms have fairly well been analyzed in many animals.

Compass mechanisms
How do animals proceed when they have to locate directions? In principle, they use the same factors that we humans, too, use, namely the geomagnetic field and astronomical cues. Three compass mechanisms have been identified in animals, namely a How do animals proceed when they have to locate directions? In principle, they use the same factors that we humans, too, use, namely the geomagnetic field and astronomical cues. Three compass mechanisms have been identified in animals, namely a magnetic compass, a Sun compass for directional orientation during the day and a star compass for orientation at night magnetic compass, a Sun compass for directional orientation during the day and a star compass for orientation at night

The magnetic compass
We humans need a technical device-a compass where a magnetic needle aligns itself with the course of the field linesto locate the direction of the geomagnetic field. Many animals, in contrast, can sense the direction of the magnetic field directly.

The distribution of a magnetic compass among animals
A sense for magnetic directions was first discovered in migratory birds: During the migratory season, these birds show a spontaneous tendency to prefer their migratory direction also in suitable cages, and when the north of the ambient magnetic field was shifted by a coil system, European robins (Erithacus rubecula, Turdidae) changed their preferred direction accordingly (Fig. 1a, b) [5]. These findings initially met with considerable skepticism because it was a novel, unexpected sensory ability alien to man. Meanwhile, however, a magnetic compass has been demonstrated in more than 20 bird species, including other migrants and also in non-migrants, e.g., homing pigeons [6] and even domestic chicken (Gallus gallus domesticus) [7]. It was also found in animals of other groups, first in cave salamanders [8], but soon also in all groups of vertebratesin fish such as stingrays [9], salmons [10,11], eels [12,13] and others, in frogs (e.g., [14]), alligators [15], marine turtles [16] and mammals like rodents [17] and bats [18]. Findings in humans have been controversially discussed (see [19]).

Different functional modes
The magnetic compass in animals is not a uniform mechanism, however. It has been analyzed in detail only in very few species so far, but there are at least two fundamentally different functional modes and some modifications. The mechanisms in birds are the ones best known so far and, here, the magnetic compass functions very differently from our technical compass.
Birds are not sensitive to the polarity of the magnetic field (see Fig. 1a, c); instead, they sense the axial course of the field lines and distinguish between their two ends by the inclination [30]. This means that for birds, the magnetic compass does not indicate magnetic north and south, as our technical compass does, but poleward, where the field lines point downward and equatorward, where they point upward. This type of compass, an inclination compass, becomes ambiguous at the magnetic equator and requires long distance migrants to 'reverse' their heading from equatorward to poleward when they cross the equator to continue heading southward. The inclination compass was first analyzed in European robins, but was also found in all other bird species tested for it so far. It is remarkably accurate; it was shown to still work at an inclination of 87•, i.e., only 3•from the vertical [31,32] and at 5•, close to the horizontal [33].
The avian magnetic compass proved to be light dependent, requiring short wavelength light from UV to about 565 nm green (see Fig. 1); under red light, birds are disoriented [34][35][36]. It spontaneously functions only in magnetic intensities with which the birds are familiar; decreasing or increasing the ambient intensity about 25% leads to disorientation [37,38]. However, birds can adjust to intensities outside this functional window when they are exposed to other intensities for a while: Robins caught and kept in a field of 46 µT thus became able to orient at intensities as low as 5 nT [39] and as high as 150 nT, but could not orient at the intermediate intensity of 81 nT [37]. This ability allows migrating birds to cope with the decreasing intensities that they encounter when reaching lower latitudes.
These characteristics of their magnetic compass indicate that birds have a specific way to perceive magnetic directions. In the 1980s, Schulten and Windemuth [40] suggested the radical pair model, which was later detailed by Ritz and colleagues. It assumes the avian magnetic compass to be based on radical pair processes, with the direction of the ambient magnetic field changing the ratio singlet/triplet of the radical pair (for details, see [41]). This effect does not depend on the polarity of the magnetic field and thus results in an inclination compass as found in birds. As site of magnetoreception, the authors suggested the eyes, because of their spherical shape, and there are receptor cells aligned in all spatial directions.
Hence the different ratio of singlet/triplet would result in an activation pattern on the retina that is centrally symmetric to the course of the field lines (see [41] for details). Changes in intensity would modify the activation pattern, which appears to confuse the birds at first, but since the pattern retains its central symmetry to the field lines, birds can learn to interpret the altered pattern.
As receptor molecule providing the radical pairs, Ritz and colleagues suggested cryptochrome, a protein with FAD (flavin adenine dinucleotide) as chromophore [41], because it is the only known photo pigment in animals that forms radical pairs. Several types of cryptochromes were indeed found in the retina of birds (see, e.g., [42]). In particular Cry1a, located in the outer segment of the V/UV receptor cells of robins, chickens and zebra finches (Taeniopygia guttata, Estrldidae) seems highly suitable for magnetoreception. These cells are distributed all across the retina [43,44] and thus could produce the assumed activation pattern.
Cry1a is activated at all wavelengths where birds were found to be oriented [45]. Later studies indicate that the crucial radical pair is formed during reoxidation ( [46]; for review, see [42]).
Amphibians and marine turtles were also shown to have an inclination compass, i.e., a compass that is not sensitive to the polarity of the magnetic field. Their compass mechanisms, however, were found to differ from that of birds in their light dependency. While birds are still oriented under 565 nm green light, the wave length range of normal orientation in the newt Nothophthamus (Salamandridae) appears to end at about 450 nm blue [47]. Marine turtles, in contrast, could use their inclination compass also in total darkness [48].
Only little is known about the magnetic compass of other vertebrates .A few fishes and mammals have been studied: salmons [49], subterranean rodents [50], and bats [51] were found to respond to the polarity of the magnetic field-they have a polarity compass. Details of their reception mechanisms have not yet been analyzed; permanent magnetic material like magnetite (a specific form of iron oxide, Fe(II)Fe(III)2O4) has been discussed.
Even less is known about the functional mode of the magnetic compass of arthropods. Among crustaceans, only the compass mechanism of spiny lobsters has been analyzed; they were found to have a polarity compass [52].
The two species of insects tested so far, the flour beetle Tenebrio [53] and the monarch butterfly [54], in contrast, have an inclination compass.
The different functional modes of the magnetic compass suggest independent evolutionary developments. The magnetic compass is an important orientation mechanism with the great advantage of being always available, independent of the time of the day and the weather conditions. Magnetic disturbances, such as magnetic storms and local anomalies, are rarely strong enough to interfere with it.

The Sun compass
The Sun is widely used for direction finding during the day. The first indications of the Sun as an orienting cue were already reported in the beginning of the twentieth century, when Santschi [55] could redirect ants by reflecting the Sun with a mirror. In 1950, the Sun compass was discovered independently in animals as different as birds [1], and in honeybees [2]. This initiated a systematic search for Sun compass orientation in the animal kingdom. Soon a Sun compass was found in various crustaceans (summarized by [56]), various insect groups like ants and bees, beetles and others, spiders (summarized by [57,58]), butterflies like the Monarch [59], and marine snails [60]. Among vertebrates, it was found in several species of fishes (e.g., [61]; for review see [62]), in reptilian species such as lizards [63], snakes [64,65], turtles [66,67] and alligators [68]). Yet in amphibians (e.g., [69]) and mammals, where rodent species were tested (e.g., [70]), the data were less clear. It has to be considered, however, that amphibians mostly avoid being exposed to clear sunlight, and rodents are mostly nocturnally active.

Functional mode and ontogeny of Sun compass orientation
To derive directional information from the Sun, the animals must know the Sun's arc and consider the time of the day. This does not pose a problem, because animals are endowed with an internal clock. Their endogenous circadian rhythm is synchronized with the natural day by sunrise and sunset, (see, e.g., [71]). With this sense for the time of the day, they interpret the Sun's position. The customary demonstration of Sun compass use is based on this phenomenon. In the socalled clock-shift experiments, the internal clock of the test animals is shifted, mostly for 6 h, by subjecting them to an artificial photoperiod that, e.g., starts 6 h before sun-rise and ends 6 h before sunset. After about 5 days, the internal clock is adjusted to the new, artificial photoperiod. When the animals are then exposed to the Sun, they misjudge its position and orient in a direction that deviates markedly from that of untreated controls-in the Northern Hemisphere, a forward shift results in a counterclockwise, and a backward shift in a clockwise deviation (Fig. 2). Such clockshift experiments were first conducted by Schmidt Koenig [71] with homing pigeons, but soon this method has been widely applied, e.g., also in connection with directional training (see e.g., [72]) When animals are tested in a clock-shift experiment, the altitude of the Sun is markedly different from what they should expect according to their subjective time, e.g., 6 h forward shifted pigeons tested at 6:00 in the morning should expect the Sun high up in the sky because this is their subjective noon; instead it is low above the horizon. They seem to ignore this discrepancy, however, which indicates that for the Sun compass of birds, only the Sun's azimuth is important, whereas its altitude is ignored. Schmidt-Koenig therefore describe the Sun compass of pigeons as a Sunazimuth compass ([72]; see also, e.g., [73] for ants). The same seems to apply to many other animals; for fishes, however, the Sun's altitude seemed to be also involved in the orientation process (see e.g., [74]).
Yet the Sun's azimuth does not change uniformly in the course of the day; just after sunrise and just before sunset, when the Sun rapidly gains or loses altitude, its increase is rather slow, below the average of 15•per hour, whereas around noon, when the Sun is high up in the sky, it moves much faster. This raised the question whether the animals are aware of this and compensate for the changes in azimuth correctly. This was first demonstrated in the desert ant Cataglyphis (Formicidae): These ants are aware of the different rates of change in the course of the day [73] and interpret the Sun's azimuth accordingly. The same appears to apply to honeybees [75,76]. Fishes, too, consider the different rates of change in Sun's azimuth largely correctly [77], and this is also true for birds [78].
The Sun's arc, however, and with it the rate of changes in azimuth, depends on the geographic latitude and season. This means that for precise Sun compass orientation, the animals' compensation mechanisms must be based on the true Sun's arc of their home region and the correct time of the year. This is accomplished by learning processes: ants and bees observe the sky before they begin the foraging phase of their life. These learning processes are rather fast, taking only a few days, and seem to be supported by innate components (see e.g., [79] for details)-ants that had experienced the Sun only early in the morning could interpret its position in the afternoon correctly [80]. This is probably required because of the rather short life span of these social insects, which also makes an adaptation to the seasonal changes largely unnecessary. Ants that have overwintered, however, must learn the Sun compass in spring anew [81], which may also apply to over wintering bees.
In birds, the ontogeny of the Sun compass has been studied only in homing pigeons. Here, it is likewise learned [82], with the learning processes taking considerably longer and requiring observation of the Sun's arc during large portions of the day. Birds that had experienced the Sun only in the afternoon could not use their Sun compass in the morning [83]. Learning the Sun compass normally begins when the pigeons are about 12 weeks old, but it can be advanced by early flying experience [84]. The magnetic compass serves as reference against which the movement of the Sun is observed [85].
We tend to assume that the respective processes are similar in all bird species. How the avian Sun compass is adjusted to the seasonal changes has not yet been analyzed; it is to be expected, however, that the processes are similar to those of its first establishment. Little is known about the establishment of the Sun compass in other animals. Experiments with fishes that never saw the natural Sun suggested that their Sun compass may be in large parts innate (see [85]).
The Sun compass is the most important orientation mechanism within the animals' home range and over shorter distances, where animals follow their Sun compass in spite of contradicting information from their magnetic compass. During long range migrations, however, animals would have to additionally cope with the changes of the Sun's arc with geographic latitude or, when they migrate east/west, with the resulting shift in local time. Interestingly, while a Sun compass was demonstrated in numerous fish species (see e.g., [60,61], experiments involving migration with species like salmons and eels failed to produce unequivocal evidence for Sun compass orientation [87,88]. With birds, the Sun compass is likewise demonstrated in displacements and conditioning (see e.g., [89] for summary), but day migrating birds during migration did not respond to clock shifting as expected (e.g., [90]). The findings suggested that they paid attention to the Sun, but that the Sun compass does not serve as major compass system for orienting the migration flight.

The role of polarized light
The Sun is accompanied by a particular pattern of polarization in the sky light, with the polarization reaching a maximum 90•from the Sun. It gradually changes as the Sun moves. In contrast to us, many animals can see this polarization pattern in the sky and use it for orientation, so that for them, the Sun compass is actually a 'skylight' compass (see e.g., [91]). The pattern of polarization is also visible below the water surface (see e.g., [92]) so that polarized light is also a potential orientation cue for aquatic animals living near the surface.
The use of polarized light for orientation was first discovered in honeybees and ants [95,96] and in the following years was also found in many other insect species. In insects, where the upper parts of the eyes are specialized to detect the polarization of light (for reviews, see e.g., [57,97]; for details about the insects' polarization vision, see e.g., [98]). Experiments with desert ants of the genus Cataglyphis showed that these ants are familiar with the polarization pattern and its changes in the course of the day; they use it for compass orientation [80]. They need not see the entire sky, but a small portion is suffcient. Dung beetles have even been reported to be able to use the polarized moonlight for nocturnal orientation [99].
Many vertebrates, too, are sensitive to polarized light. This is indicated in fishes (e.g., [100]), amphibians [101], reptiles (e.g., [102,103]) and, among mammals, bats [104]. Birds are also able to perceive polarized light [105] and with them the effect of polarized light on orientation behavior has been studied in some detail.
The pattern of polarized light at sunset was shown to play some role in the orientation of a night migrating American songbird [106] that starts migra-tion flight at about that time. Several authors began to test the relative importance of polarized light compared to other cues, with some studies appearing to indicate a dominance of polarized light [107][108][109]. Several of these studies are not unproblematic, however, because they involved polarizers, which polarize the entire skylight almost 100%, and this unnatural pattern appears to alter the normal behavior. Birds were observed to orient roughly parallel to the axis of polarization, which was significantly different from their response to the natural polarization pattern [110]. A dominant role of polarization could not be generally confirmed (e.g., [111,112] a.o.).
Yet migratory birds can use the natural polarization pattern for orientation. A twilight migrant stayed oriented when other orienting cues like the geomagnetic field had been removed (e.g., [113]), and this is also applicable for a day migrant. In a compensated magnetic field, the birds were still oriented as long as the natural skylight was visible, even when the Sun itself was obscured [114].
A crucial role of polarized light is also that it can mediate celestial rotation to migratory birds, which is an important factor for transforming the genetically coded information on the migratory direction into an actual direction (see below). This effect was only observed in birds that had full view of the natural sky, whereas birds that had observed the sky through depolarizers could not do so, even if they had been able to see the Sun and its movement [115].
The Sun compass, i.e., the skylight compass, is the dominant mechanism in the compass orientation of many animals: They prefer to use it when it is available.

The star compass
Using the stars for orientation has been described so far only for nocturnally migrating birds; they can use the stars as a compass. This was first demonstrated in planetarium experiments.
A star compass is also indicated by outdoor experiments, where birds at night headed in their migratory direction with the stars as only available cue (e.g., [118][119][120]).
The stars move in the course of the night, but an analysis of the star compass showed that the internal clock was not involved [121]. This excluded mechanisms similar to that of the Sun compass (see above) and spoke against the use of individual stars, suggesting that birds might derive directions from the pattern as a whole or parts of the pattern. Experiments blocking certain constellations revealed a considerable individual variance. In general, the circumpolar stars within 35•of the center of rotation center seemed to be important, yet the results did not allow a final conclusion [121].
The star compass is also a learned mechanism. Young migrants could use the stars as a compass only if they had observed the sky rotating before they start autumn migration. In an experiment, two groups of hand raised birds were exposed The Sun compass, i.e., the skylight compass, is the dominant mechanism in the compass orientation of many animals: They prefer to use it when it is available.
to a rotating planetarium sky, with the control group under the normal sky, rotating around the polar star Polaris, while the test group was exposed under a sky rotating around Betelgeuze in Orion. Later, during autumn migration, both groups were tested under the now stationary planetarium. The control group preferred the normal southerly migratory direction, heading away from Polaris, whereas the test group headed away from Betelgeuze [122]. Birds do not seem to have an innate concept about what the sky looks like. The complex natural sky could be replaced by a simple pattern of only 16 light dots-as long as the birds had observed this pattern rotating with 1 rotation per day, they later could use it to orient in their migratory direction relative to the center of rotation [123,124]. Celestial rotation was thus identified as the crucial factor for establishing the migratory direction with respect to the stars.
The view of the sky changes gradually. The stars rise 4 min earlier each day, so that the sky in autumn looks different from that in spring. At the same time, the sky changes its appearance with geographic latitude. During autumn migration, as the bird moves south, the northern stars slowly lose altitude and approach the horizon, while new stars appear at the southern horizon. Birds have to integrate these new stars into their star compass. Experiments under the natural sky with altered magnetic fields indicate that the magnetic compass provides the reference system which gives directional meaning to the new stars during migration (e.g., [118,119], a.o.).
So far, a star compass has been demonstrated only in a few species of songbirds that migrate at night. Since the majority of birds are primarily day active, the star compass could be a special mechanism developed by the nocturnal migrants to orient their extended flights. It is unknown whether generally night active birds, like, e.g., nightjars or owls, also use the stars as a compass as such birds have not yet been studied.

FUKUI COMPUTER partners with Bentley Systems
FUKUI COMPUTER, Inc has entered into a strategic partnership with Bentley Systems to accelerate the adoption of digital workflows in the Japanese construction industry and support the promotion of digital transformation (DX) in the infrastructure field. It will leverage the Bentley iTwin platform to augment its cloud-based data sharing service CIMPHONY Plus with 3D/4D visualization, simulation, and digital twin capabilities. The company will launch a digital solution that supports the entire infrastructure lifecycle, spanning project management, design, construction, and maintenance. www.bentley.com

NGS releases NGS map to production
The NGS map provides the ability to view multiple datasets provided by the National Geodetic Survey. These datasets are: This application not only allows users to plot these datasets but there is a measuring tool available, multiple basemaps, a select tool to select and export data as well as an attribute Simply by virtue of physics, with less of a distance to cover down to Earth, the signals from these LEO-PNT satellites can be more powerful, able to overcome interference and reach places where today's satnav signals cannot reach.
And by adopting novel navigation techniques and a wider range of signal bands the satellites can address particular user needs: for instance at lower orbits the satellites themselves move more rapidly relative to Earth's surfacethink of the International Space Station at 400 km that orbits the Earth every 90 minutes -which offers possible advantage in the time needed to reach very accurate positions. Also some bands could offer greater penetration in difficult environments while other bands could offer higher robustness and precision.

JAVAD GNSS Announces New Products
JAVAD GNSS launchd new GNSS products for geospatial applications.
The TRIUMPH-1M Plus and T3-NR smart antennas bring the latest satellite tracking technology into the Geopspatial portfolio using GNSS and inertial sensor fusion augmented by updated modules for UHF, Bluetooth, Wi-Fi, and power management.
The RS-3S is a rugged, mountable GNSS enclosure equipped with the latest tracking technology designed for outdoor use. The new Victor-2 and Victor-4 rugged field computers for data collection has also been introduced. The Victor-2 features an inbuilt keyboard with a classical data collector look and feel, while the Victor-4 is an 8-inch tablet optimized for field use. Both solutions will run the new J-Mobile for AndroidTM data collection software. J-Mobile is optimized with userfriendly workflows and industry-standard menu structures for immediate use with minimal training. www.javadgnss.com

Rx Networks collaborates with Qualcomm
Rx Networks, Inc. announced the availability of TruePoint.io precise location services on Snapdragon 8 Gen 1 and Snapdragon 888 5G Mobile Platforms. TruePoint.io integration empowers Android smartphones to achieve enhanced location accuracy down to a meter or lesssomething only previously seen with highgrade receivers. https://rxnetworks.com

Hexagon & LocLab partnership
Hexagon's Geosystems division and LocLab announced a strategic partnership to jointly empower industries with Smart Digital Realities in their design, construction and operations processes.
The strategic partnership is focused on increasing the automation of 3D digital twin creation by leveraging reality capture solutions and making digital twins seamlessly accessible to customers by connecting them with HxDR, Hexagon's cloud-based storage, visualisation, and collaboration platform for reality capture and geospatial data. www.hexagon.com

Trimble & General Motors marks milestone in semiautonomous driving
General Motors and Trimble recently reached a milestone in the handsfree driving world-more than 34 million miles driven with Super Cruise engaged on General Motors vehicles.
The partnership aims to develop a reliable way to maintain in-lane positioning for hands-free driving, putting safety top-of-mind. www.trimble.com

Hemisphere GNSS Introduces GradeMetrix® Scraper
Hemisphere GNSS, Inc. has announced the release of the GradeMetrix® Scraper Solution for pull pan and belly pan scrapers.
The kits will be available for purchase for new customers. Existing customers will have the option to add scraper support to their current GradeMetrix® system via a software upgrade and machine activation. www.HGNSS.com

Lantronix launches new GNSS receiver modules
Lantronix Inc. has launched its new PNT Series GNSS Receiver Modules. It provide an easy-to-use, cost-effective solution to enable the addition of GNSS functionality to products. The receiver modules are appropriate for use in consumer solutions, including people/pet and asset tracking devices etc. lantronix.com

Spirent GNSS simulator integrated with MVG over-the-air test systems
Spirent GSS7000 GNSS simulator has been integrated into Microwave Vision Group (MVG) over-the-air (OTA) and passive antenna test systems. MVG enables the characterization and evaluation of antennas for testing x NEWS -UAV UAV Navigation defines operational envelope for VECTOR-600 autopilot An independent study conducted by UAV Navigation has defined the operational envelope of the VECTOR-600 autopilot based on the Specific Operations Risk Assessment (SORA) methodology. The operational envelope defines the operational risk profile within which an aircraft can operate safely, taking into consideration all risk mitigations included within the system.
The SORA methodology evaluates the safety risks involved with the operation of an unmanned aerial system (UAS) of any class, size or type of operation. The concept of operation (ConOps) is normally used as the input for this analysis; the output takes the form of the Specific Assurance and Integrity Level (SAIL) for a particular operation, which indicates the level of robustness that must be demonstrated for the operational safety objectives.
In this case, instead of performing a conventional SORA analysis from the ConOps to the SAIL output, this study was performed the other way around because the objective of the study was to identify the operational envelope of the sytem. www.uavnavigation.com

LidarSwiss deploys Cepton lidar for high-fidelity mapping
Cepton announced that it is working with LidarSwiss Solutions GmbH to deploy its lidar technology in a dronebased mapping and analytics solution for infrastructure management and engineering design applications.
Nano P60 integrates Cepton's Sora sensor with a high-precision IMU/ GNSS unit and a high-resolution camera system. Its intelligent controller with LidarSwiss proprietary software automatically combines all raw data to generate high-density, high-precision RGB-attributed 3D laser point clouds during flight. www.lidarswiss.com x wireless connectivity, reliability, and standards compliance. MVG near-field test systems perform fast and accurate measurements for OTA tests of antennas designed for satellite communications and other GNSS-enabled products, systems, and networks. www.spirent.com

Mosiac integrates RIEGL Mobile Mapping Systems
Mosiac has announced its product portfolio would integrate RIEGL's mobile mapping systems to gather more advanced 3D data. The technology alliance also allows Mosiac end-users to record and analyse 3D object surfaces and environments to assist with city planning, construction, and maintenance.

Hi-Target GNSS receiver
The pocket-sized vRTK GNSS real-timekinematic (RTK) receiver is equipped with dual cameras to enable non-contact image surveying. It also has a nine-axis IMU module with auto installation for tilt surveying. Visual positioning technology combines imagery with high-precision positioning equipment, allowing users to obtain the location of the target from a distance. The Live View Stakeout function improves stakeout speed, while non-contact measurement greatly improves the usable range of GNSS. The miniature inertial sensor embeds a dual frequency/quad constellations GNSS receiver for centimetric position with a high performance IMU into a compact form factor, according to a news release. The RTK capable sensor is 50 x 37 x 23 mm and weighs 38g. It offers roll/pitch with less than 0.02° error and heading with less than 0.06° error.
Even though it comes in a small form factor, the sensor embeds all the features found in other SBG inertial sensors, including a built-in datalogger, Ethernet connectivity, a PTP server, multiple serial ports, and a CAN port. A builtin, user friendly web configuration interface makes it easy to configure. The sensor also be configured using SBG API or ROS drivers. The Quanta Micro supports dual GNSS Antenna mode to improve heading accuracy in low dynamic applications, but also can maintain optimal heading performance in a single antenna.

Topaxyz, the high-performance navigation solution
Thales offers the TopAxyz solution, a control unit that provides navigation, orientation, position and velocity data based on measurements of the vessel's angular velocity using its inertial core.