I suspect you’ve already done considerable work looking for the files. Every NASA and USGS link I followed is now dead. What I did find may only be in ARC Grid or ARC ASCII format pushed by ARCGIS or ASTRA(sp?).
Probably the first thing I should tell you is that after my experience watching the USGS relocate their data every year or so, I used your program to download the entire global dataset from whichever working site was available at the time, version 2_2. I don’t remember if its zipped or not, .htg and 3.5 GB, but if you can find a site to store it, I’m willing to reinstall an ftp program and upload the folder.
I did find an interesting site, vterrain.org, with links to ftp download pages, which I copied as there is a difference between clicking their links and copying the links into a web browser. For what it might be worth...
http://vterrain.org/Elevation/SRTM/ftp://ftp.glcf.umiacs.umd.edu/glcf/SRTM/
ftp://srtm.csi.cgiar.org/SRTM_v41/
I'm guessing you've found the CGIAR site. Nope, not looking very useful, but I don't currently have an ftp program installed to test the CGIAR links mentioned above from the vterrain.org site. (
https://srtm.csi.cgiar.org/)
It looks like someone in government decided to offload handling of the data to a “community organization”, CGIAR / CIAT-CSI. If anyone else if hosting, I didn’t find it in my morning of searching. To me, it looks like name-in-lights for the organization and it’s head honcho if you use their service for non-commercial use. Like I said, that’s what it looks like to me.
Perhaps you can contact him and let him know what you’d like to do. Heck, he might hire you. They’ve apparently updated the data for shorelines and smoothed over voids. He calls it version 4.1.
The one interesting page I did find looks like it will be unusable as it seems to require manual downloads per tile, but they have the data and that ftp link might be key.
The README file of the srtm_31_05.zip file I downloaded from
https://www.usna.edu/Users/oceano/pguth/md_help/html/srtm.htm says this:
The data distributed here are in ARC GRID, ARC ASCII and Geotiff format, in
decimal degrees and datum WGS84. They are derived from the USGS/NASA SRTM data.
DISTRIBUTION
Users are prohibited from any commercial, non-free resale, or redistribution
without explicit written permission from CIAT. Users should acknowledge CIAT as
the source used in the creation of any reports, publications, new data sets,
derived products, or services resulting from the use of this data set. CIAT also
request reprints of any publications and notification of any redistributing
efforts. For commercial access to the data, send requests to Andy Jarvis
(a.jarvis@cgiar.org). [NOTE: this is he same guy at CGIAR]
Once unzipped, I found the readme, a 5 line prj text file and the 886KB .asc ASCII file, started out this way:
ncols 6000
nrows 6000
xllcorner -30
yllcorner 35
cellsize 0.00083333333333333
NODATA_value -9999
-9999 -9999 -9999 -9999 -9999 -9999…
A UTube video made EarthExplorer look interesting but not particular useful for your program.
