[postgis-users] Extracting cell values into a matrix

[DavidRA]

Hi, I need to develop a tool that is able to connect with PostGIS and extract
the cell values from a raster stored in it creating a matrix with them. It
could be done with queries launched from that tool, using ST_Value(), for
each cell, but the number of queries would be huge.

Instead, I think it's better to create a PostGIS function that is
responsible for creating the matrix, so from the external tool I just have
to make one single query. This is what I have right now:



But this has two problems:

- I don´t know how to see the results. If I do "SELECT ST_ObtainMatrix(rast)
FROM raster_table", pgAdmin shows a white record. Supposedly, it has
"something" inside, but...

- With high resolution rasters (very small cell size) this is awfully slow,
as I feared.

Do you have any better ideas on this matter? Thanks!

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