Add SRTM data source

[APatrickJ]

This is a digital elevation map created by NASA's Shuttle Radar Topography Mission.

We need to make sure we're using the V3 product (SRTM Plus) which has:

• 30m / 1 arc-second spatial resolution
• Void filling (see https://lpdaac.usgs.gov/documents/13/SRTM_Quick_Guide.pdf)

USGS provides small scale downloads via EarthExplorer.

For a bulk download, this looks like one possible source:
https://portal.opentopography.org/raster?opentopoID=OTSRTM.082015.4326.1

[favyen2]

maybe https://e4ftl01.cr.usgs.gov/MEASURES/SRTMGL1.003/

[APatrickJ]

@favyen2 Hmm, I'm getting an error when I try to access that. Can you share a screenshot or description of what it is?

[favyen2]

Hm I guess downloading the files still requires EarthData login (https://urs.earthdata.nasa.gov/). It has the per 1x1 degree zip files