search for: st_setvalues

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2013 Oct 08
0
PostGIS 2.1 rasters available to Rails code: breadcrumbs
...easons. But even the fabulous RGeo gem doesn''t know from rasters, or at least not yet AFAIK. So there''s no way to get pixels out of the raster except one-by-one with an ST_Value query; for a 297x582 array, a nonstarter. Enter PostGIS 2.1 and its lovely lovely ST_DumpValues and ST_SetValues functions. By using the connection''s select_value method, we can return an arbitrary SQL result as a string, in this case a 2D array coded with the PostgreSQL convention of { and } where Ruby uses [ and ]. Likewise, connection.update can take an SQL string, and we can wad a 2D array o...