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bopen / elevation

Python script to download global terrain digital elevation models, SRTM 30m DEM and SRTM 90m DEM.
http://elevation.bopen.eu
Apache License 2.0
290 stars 74 forks source link

SRTM 30m data coverage #29

Closed leroygr closed 9 months ago

leroygr commented 6 years ago

Hello,

I have a question regarding the coverage of srtm 30m data that are downloaded from S3. From your README, it mentions that the 30m data comes from the global datasets SRTM 30m Global 1 arc second V003 elaborated by NASA and NGA. When looking at the link, it says that the spatial extent is "Global (60°N to 56°S, 180°W to 180°E)".

However, I downloaded a tile beyond the extent mentioned (skadi/N65/N65E015.hgt.gz) and I do have elevation data in that area that is supposed to be outside the coverage: image

When looking at Mapzen websites, it says that they provide worldwide basemap coverage sourced from SRTM and other open data projects with several different data formats and varying levels of processing.

So my guess is that the elevation data downloaded from s3 bucket (skadi) are a mix of different sources and not only the original srtm data.

Could someone clarify this?

Thanks a lot, Greg

molind commented 2 years ago

Hi, there is a documentation about the process and datasources used to build skadi dataset. https://github.com/tilezen/joerd/blob/master/docs/data-sources.md