fix satelite background projection glitches

[namdre]

• downloaded satelite imagery (add webwizard checkbox to download satelite background for generated scenario #6481) is using the global mercator projection (a web mapping standard)
• netconvert uses UTM to project OSM data by default (less projection errors for typical scenarios)

The differences in coordinate transformation leads to gaps in the satelite background

Possible solutions:

• use gdalwarp or python gdal.Warp to reproject the satelite images -> creates additional dependencies. see

  • https://gis.stackexchange.com/questions/139906/replicating-result-of-gdalwarp-using-gdal-python-bindings
  • https://stackoverflow.com/questions/48706402/python-perform-gdalwarp-in-memory-with-gdal-bindings
  • https://gis.stackexchange.com/questions/247871/convert-gps-coordinates-to-web-mercator-epsg3857-using-python-pyproj

• when using the 'satelite background' in webwizard, set the netconvert projection to global mercator -> creates (bigger) distortions in generated network.

The required netconvert option is
--proj "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"

source: https://epsg.io/3857

[BjoernPK]

I just recently encountered this problem and wanted to check on the status. Is it possible to manually run the projection of tiles downloaded via tileGet.py? If so, is it sufficient to run netconvert on the settings.xml created with the downloaded tiles? Or do I have to run it on the net file that is linked to the settings.xml? Which command do I have to use for this?

I would be very happy to receive your feedback - thanks in advance! :)

[namdre]

assuming you have a webWizard-derived scenario, this is what you need to run:

netconvert -c osm.netccfg --proj "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"
tools/tileGet.py -n osm.net.xml -t 100 -d background_images -l -300