BD Ortho 5 m — aerial photography (reformatted)
Description
The original files released by IGN on http://professionnels.ign.fr/bdortho-5m under Open License are:
— in legal projection (Lambert 93 in metropolitan France and other specific projection for each DOM)
— in JPEG2000 format “lossless” per slab of 10 km x 10 km
— compressed as a 7z archive (long to be decompressed for marginal compression gain, with slabs already compressed)
In order to make these aerial images more directly usable, for example on a website or an embedded application (an average department is 150 MB), the files proposed here are:
— in projection Web Mercator (EPSG:3857)
— in GeoPackage OGC format, with JPEG compressed content (quality 75)
— each department is provided in a single standalone file, with no additional compression
They are ultimately about 10 times less voluminous and more directly exploitable.
## Applied treatments
They are made with [gdal](http://www.gdal.org) and the following parameters:
“'”
gdalwarp/tmp/$D.vrt $D.gpkg -t_srs EPSG:3857 -r cubic -of gpkg -overwrite -multi -cutline/tmp/$D.shp -crop_to_cutline -dstalpha
gdaladdo $D.gpkg -r average --config COMPRESS_OVERVIEW JPEG --config PHOTOMETRIC_OVERVIEW YCBCR --config INTERLEAVE_OVERVIEW PIXEL 4 16 64
“'”
Resources
| Name |
Format |
Description |
Link |
|
0 |
|
https://www.data.gouv.fr/fr/datasets/r/8e2f2627-1dc7-4515-ad0a-5367b2bc824e |