Using Geoid (EGM2008) as dataset

[arkonsolutions]

Hello!

Please tell me how to approach this task and where to start.

Right here (https://geographiclib.sourceforge.io/C++/doc/geoid.html ) there are links to world-wide geoid files, they can be downloaded and converted to tif.

[arnesetzer]

Well, convert them into a geotiff or srtm syntax and create a entry in the config.yaml. I just had a quick look, but it seems like, that gdal can handle .pgm files so that shouldnt be a problem.

[arkonsolutions]

Yes, I have succeeded in this case.

My steps (Windows 10 + wsl):

• Downloading and unzipping a PGM file.

  wsl
  cd /mnt/c/
  mkdir Volumes/egm2008-5
  cd Volumes/egm2008-5
  wget https://sourceforge.net/projects/geographiclib/files/geoids-distrib/egm2008-5.tar.bz2
  tar -xjvf egm2008-5.tar.bz2

• Convering PGM to GeoTiff

  mkdir geotiff
  cd /mnt/c/Volumes/egm2008-5/geoids
  gdal_translate -ot Float32 -scale 0 65000 -108 87 egm2008-5.pgm ../geotiff/egm2008-5.tiff

• Opentopodata config.yaml

  
  max_locations_per_request: 100 
  datasets:

• name: egm2008-5 path: /app/data/egm2008-5/geotiff

* Assemby and run opentopodata

cmd (not wsl):

cd opentopodata docker build --tag opentopodata --file docker/Dockerfile .

docker run --rm -it --volume "C:/Volumes/:/app/data:ro" -p 5000:5000 -e N_UWSGI_THREADS=8 opentopodata sh -c "/usr/bin/supervisord -c /app/docker/supervisord.conf"

Results:

take a location:
10.168455, 49.402717

Online GeoidEval calculator
https://geographiclib.sourceforge.io/cgi-bin/GeoidEval?input=10.168455+49.402717&option=Submit
returns: -29.4900

GET http://localhost:5000/v1/egm2008-5?locations=10.168455, 49.402717

{ "results": [ { "dataset": "egm2008-5", "elevation": -29.48802375793457, "location": { "lat": 10.168455, "lng": 49.402717 } } ], "status": "OK" }```

[ajnisbet]

Oh cool, thanks for reporting back with instructions!!!