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I have SRTM data at 90m resolution downloaded and I need to calculate slope (in degrees). I'm using the GDAL python library and command line tool for everything. GDAL can read in hgt files (SRTM files) and can make slope maps, but these tend to be inaccurate the farther away from the Equator I go if I don't reproject.

Therefore I need to reproject my files to a different CRS but I'm not sure how to pick one.

I have ~10k instances of landslides from a dataset (the global landslide catalog), and for each instance I need to find the 90th percentile of slope in a little bounding box around the landslide location (size of box depends on precision of estimate, which is known).

The distribution of the dataset looks like this: enter image description here

So, my questions are:

  • What CRS is a good one to pick?
  • Do I reproject the entire global dataset to one CRS?
  • Do I reproject to different CRS's based on the lat/long (like UTM sectors?).
Vince
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Shrey Joshi
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    Are you sure you need to do the whole world in one hit? Perhaps you could edit your question to provide extent of your main area of interest and its location. Then someone could better advise you. – Leigh Bettenay Jan 20 '21 at 22:58
  • I've edited the question with more detail regarding the reasons I'm doing slope calculation. I don't have a main location since I'm doing global analysis but I put up an image showing the distribution of my dataset. – Shrey Joshi Jan 20 '21 at 23:10
  • This related question suggests a Mercator projection: https://gis.stackexchange.com/a/40464/122597 For a start, I'd try EPSG:3395 – StefanBrand_EOX Jan 21 '21 at 13:05

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