I have put the Tiled Global DTM into PostGIS. It has around 1 million rows. So, when I search for the specific raster data for my interested area (polygon), it takes almost 1 minutes to get the result. The SQL I were using is as follows:
SELECT rast FROM globaldtm WHERE ST_Intersects(rast,ST_envelope( (select geometry from polygons where id =25))); I knew there is a way to speed up this query by using spatial index. But I don't know how to get it work. Can I build my own index like creating index according to the UTM zone. Does anyone have some good example about that? Thanks. -- *YU Guo * MSc. Hydroinformatics and Water Management *Email*: *[email protected]* *Phone*: +33 668 195803
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