Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye

Muhammet Ali Aygün; Ahmet Sinan Demirel

doi:10.26650/ijegeo.1910698

Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye

Abstract

In many national geophysical surveys performed during the period from the 1950s to the 1990s, large analog archives are still not accessible to modern analysis techniques because of their printed, non-digital form. This paper presents a Python-based, fully automated workflow for the systematic digitization, georeferencing, and multi-source integration of legacy gravity and magnetic survey maps, applied to a critical geophysical archive in the southern Marmara Sea region of Turkey. The study analyzes 27 printed maps, including 15 gravity and 12 magnetic maps, from 1972 to 2000, created by three different agencies (MTA General Directorate, C&K Petroleum, Norexplo Consultant) using two self-developed Python modules. The fully digitized database contains 24,510 Bouguer gravity measurements (86 survey lines) and 25,230 reduced-to-pole (RTP) magnetic measurements (87 survey lines), amounting to 49,740 integrated data points. Cross-validation for the gravity data set gives r = 0.9996 and RMS = 0.426 mGal, and for the magnetic data set r = 0.9991 and RMS = 7.485 nT, with mean residuals close to zero in both cases, indicating the absence of systematic errors. The reconstructed Bouguer gravity field varies from −37.47 to +74.01 mGal, and the RTP magnetic field from 746.5 to 2085.6 nT over the study area (27.0–29.4°E, 40.2–40.7°N), resolving anomaly patterns at a resolution of 150-200 m, roughly 10-20 times higher than the resolution of global maps available so far. The spatial coverage is above 99% for both data sets. The workflow reaches an accuracy of 94-97% in contour recognition and saves up to 80-90% of processing time compared to manual digitization. The fully open-source Python code is made available for the reproducible recovery of printed archives on a global scale.

Keywords

References

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Details

Primary Language

English

Subjects

Geological Sciences and Engineering (Other), Physical Geography and Environmental Geology (Other)

Journal Section

Research Article

Authors

Muhammet Ali Aygün ^*
0000-0002-8580-3536
Türkiye

Ahmet Sinan Demirel
0000-0001-5291-0493
Türkiye

Publication Date

June 19, 2026

Submission Date

March 24, 2026

Acceptance Date

April 30, 2026

Published in Issue

Year 2026 Volume: 13 Number: 2

DOI

https://doi.org/10.26650/ijegeo.1910698

IZ

https://izlik.org/JA76FW55ZL

Cite

RIS / Bibtex

APA

Aygün, M. A., & Demirel, A. S. (2026). Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye. International Journal of Environment and Geoinformatics, 13(2), 162-174. https://doi.org/10.26650/ijegeo.1910698

AMA

1.Aygün MA, Demirel AS. Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye. IJEGEO. 2026;13(2):162-174. doi:10.26650/ijegeo.1910698

Chicago

Aygün, Muhammet Ali, and Ahmet Sinan Demirel. 2026. “Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye”. International Journal of Environment and Geoinformatics 13 (2): 162-74. https://doi.org/10.26650/ijegeo.1910698.

EndNote

Aygün MA, Demirel AS (June 1, 2026) Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye. International Journal of Environment and Geoinformatics 13 2 162–174.

IEEE

[1]M. A. Aygün and A. S. Demirel, “Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye”, IJEGEO, vol. 13, no. 2, pp. 162–174, June 2026, doi: 10.26650/ijegeo.1910698.

ISNAD

Aygün, Muhammet Ali - Demirel, Ahmet Sinan. “Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye”. International Journal of Environment and Geoinformatics 13/2 (June 1, 2026): 162-174. https://doi.org/10.26650/ijegeo.1910698.

JAMA

1.Aygün MA, Demirel AS. Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye. IJEGEO. 2026;13:162–174.

MLA

Aygün, Muhammet Ali, and Ahmet Sinan Demirel. “Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye”. International Journal of Environment and Geoinformatics, vol. 13, no. 2, June 2026, pp. 162-74, doi:10.26650/ijegeo.1910698.

Vancouver

1.Muhammet Ali Aygün, Ahmet Sinan Demirel. Automated Digitization and Integration of Legacy Geophysical Maps: A Reproducible Python Workflow for Analog Archive Recovery Applied to the Southern Marmara Sea, Türkiye. IJEGEO. 2026 Jun. 1;13(2):162-74. doi:10.26650/ijegeo.1910698