I have 10 tables with different attributes. Geometries are grid polygons. Each table have their own gridID
numbering, so that cannot be used for joining.
Pure union of tables producing total of 2 600 000 rows. Roughly 60 percent of grid polygons have exactly the same geometry. They do overlap exactly.
I need to reduce the number of rows in order to speed up further spatial analysis.
How to combine tables so that each unique geometry is listed once.
Table1
text1a, text1b, geom1
Table2
int2a, int2b, geom2
TableN
varN1, varN2, geomN
Expected result:
All distinct geometries, one row for each.
Each row contains all attribute columns.
Null values in columns if there is no exactly matching polygon existing in table in question.
unique_geom, text1a, text1b, int2a, int2b.... varN1, varN2
Tools I have PostGIS & QGIS