You have already received good Perl answers. I nevertheless want to flag about the potential complexity of this issue. Think about what do you mean exactly by "combine polygons", since there are several different ways to "combine" polygons (see, for example, this link). As you already noted, these operations can soon get very complicated for non regular shapes.

Reinventing the wheel is surely educative and I believe it is always worth the effort. However, if you are in a hurry and need to get job done, I would recommend exploring any of the solutions that are extensively available in Geographic Information Systems.

There are a lot of good free and open source GIS packages out there, some more advanced than others. See, for example: GRASS, QGIS, and, if you like operating on databases: Spatialite or, on a PostgreSQL database, PostGIS.

All these apply the underlying engine for spatial operations implemented in GEOS, which in turn implements specifications by Open Geospatial Consortium

Good luck!

In reply to Re: combine(merge) polygons by hda
in thread combine(merge) polygons by dideod.yang

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