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
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