Aerial photography [BD ORTHO® Historique - IGN-F] - Department of Calvados - 1984

Description

BD ORTHO® History of 1984 produced by the IGN throughout the Department of Calvados. The product BD ORTHO® Historique 1984 is a collection of digital mosaics of ancient panchromatic orthophotographs (grey levels) rectified in the projection adapted to the departmental territory (Calvados). BD ORTHO® History of 1984 is freely distributed in open license thanks to the financial support of the Department of Calvados. The ORTHO® Historical comic consists of digital images (without wrapping or overloading) and georeferencing indications. The information content allows local use up to 1: 2,000 to enhance the territory. The ORTHO® BD History 1984 offers many advantages: - land-use planning: land use, land consumption and new communication routes; - environment: coastal and forest observatory, bocage management; - communication: visualization of the evolution of the territory. The original files distributed by the Calvados Department under an open licence are: - in legal projection Lambert 93 NTF (Paris) / Lambert zone I (EPSG: 2154); - in Geotif format per 2km x 2km slab; - with a resolution of one pixel = 50 cm; - compressed as a zip archive. You will find below the links to access the ‘multi-party’ files for free download. - Make sure you have downloaded all parts: 001, 002, 003... - Put all parts in one directory - Click on file 001 (ex: tif_1984.zip.001). No need to click 002, 003, 004... Opening the .001 file opens all other parts of the archive. In order to facilitate the use of these orthophotos, the files proposed here are in GeoPackage OGC format in lambert 93. **Collection context** The number of shots needed to cover a department is large, these shots have strong disparities in sunshine, colorful appearance, landscape, behavior of objects (careers, sands, water surfaces, ...) and sometimes seasonal. In practice the process seeks to correct each image of the internal lighting and color effects related to sunlight. All images must also be homogenized. For each image an illuminance correction is applied (hot-spot and vignetting). Once this correction is applied, the images are generally equalized throughout the construction site. We can add that on some shots, the use of short focal lengths or these wide-field cameras has generated significant vignetting effects (difference of illumination between the center and the edge of the image) and more difficult to correct. **Method of collection** The Geopakage was produced from the GDAL library: * gdalbuildvrt D:\3_Ortho_1984\1984.vrt -addalpha -srcnodata 255 -hidenodata D:\3_Ortho_1984\data\*.TIF * gdalwarp D:\3_Ortho_1984\1984.vrt D:\3_Ortho_1984\1984.gpkg -t_srs EPSG:2154 -r cubic -of GPKG * gdaladdo -r cubic D:\3_Ortho_1984\1984.gpkg 4 16 64 256 For more information, see [the Isogeo catalogue metadata](https://open.isogeo.com/s/434296189d794266a04a8678e256f0c4/HiLeps3y1qrSx6aTDmKyp0spGPix0/r/eacfe91c99374537bc2f48287707251f).

Resources

Name Format Description Link
0 https://www.data.gouv.fr/api/1/datasets/r/bcff8518-4160-4308-b9f1-159297ebe812
0 https://www.data.gouv.fr/api/1/datasets/r/6b4cfbe1-b52e-4434-8b85-f493d1869b49
0 https://www.data.gouv.fr/api/1/datasets/r/77c27b64-62f3-4a61-884f-64e048588a74
0 https://www.data.gouv.fr/api/1/datasets/r/1e2e18d9-4c64-4905-a5ee-2592e6227d0f
0 https://www.data.gouv.fr/api/1/datasets/r/4bf2c5e7-85ee-447c-b254-8814afc9222a
0 https://www.data.gouv.fr/api/1/datasets/r/552c8c9e-f648-4aea-929e-c8ba3f1d66d1

Tags

  • photo-aerienne
  • historique
  • calvados

Topics

Categories