[postgis-users] Postgis Raster determine exact hull

Richard Huesken richard.huesken at gmail.com
Mon Jan 10 12:26:40 PST 2022


I'm using postgis 3.1 and I'm looking for the best way to obtain the exact
hull of a raster (excluding the nodata points). The st_minconvexhull uses
the MBR of the raster coverage, and is therefore quite fast. The result is
however not as accurate as I require.

I constructed some sql that uses st_pixelaspolygons and then does a
st_union. However, My typical raster has 256x256 points, and with several
100s of rasters this is quite slow.

Are there more clever (and faster!) ways to get the exact hull of a raster?

Thanks in advance,

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