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eldang / elevation_lookups

Takes an input file of paths described as series of points, outputs a file of data about the elevation changes along those paths.
Apache License 2.0
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SRTM lookups MVP #7

Closed eldang closed 3 years ago

eldang commented 3 years ago

This is a very minimal implementation of SRTM. The elevation module can only download source tiles, not stitch them together, and source tile breaks are on whole number degrees. So this implementation can only support input files which don't cross an integer line of latitude or longitude. The good news is that lookups are very fast: 8 seconds to process the whole Poundbury sample, + 1 if the SRTM data weren't already locally cached.

I can see a fairly straightforward way to get around the integer degrees issue by just making a series of requests to elevation, saving each tile locally and stitching together relevant chunks in memory. But it'll be just enough work to do that it seemed worth making this PR first.

eldang commented 3 years ago

Closing this PR because it has a regression for the contour line lookup. I'll investigate that tomorrow and then return.

eldang commented 3 years ago

Reopening because the regression was a false alarm. I derailed a run by changing branches while it was going, and since Python is interpreted, weirdness ensued....

eldang commented 3 years ago

One more comment: I want to do some refactoring tomorrow, unifying the two line lookup methods, so that only the point lookups are datasource-specific.