Question

I have raster table in postgresql that I create it using PostGIS raster. If I want to have average raster of 3 raster records considering that the Null pixel values shouldn’t be involved in the averaging operation. I mean that pixel values of the resulting raster record should be mean value of the corresponding pixel values of the 3 existing raster records. The raster records contain some pixels with Null values and the Null values should not be involved in the computation. Is it possible? the sample_data_link is the link for sample data which are images. If Postgis 2.0 is installed in your system the following commands in commandline of windows and for the folder you copied the sample data will create the results:
raster2pgsql -r *_cropped.tif -F -I myschema.mytable > cropped_1.sql
and
raster2pgsql -r *_cropped.tif -F -I myschema.mytable > cropped_1.sql

Answer 1

you can turn it to an array and do the computation on it and then convert the array to the raster.