topic Re: Combine different keys in overlapping polygons in Geoprocessing Questions

Combine different keys in overlapping polygons

KATBIZOU — Tue, 07 Jul 2020 16:00:21 GMT

We have a polygon layer and in some places polygons with different keys overlap. The overlapping cases vary from 2 to 4 different overlapping polygons .

When a polygon overlaps in part with another we want to spit them in more polygons (2 new polygons of the no overlapping area and one third new polygon for the overlapping area but having also the key information of the 2 overlapping polygons.

We could split them using UNION but how could we “MERGE” the different information of the common area polygons?

Any idea will be very helpful.

Re: Combine different keys in overlapping polygons

MervynLotter — Tue, 07 Jul 2020 18:17:28 GMT

Could you please explain, perhaps with an example, what you mean by merging the different information of the common area polygons? Do you want to merge the information obtained in the attribute table?

Re: Combine different keys in overlapping polygons

KATBIZOU — Thu, 09 Jul 2020 07:06:45 GMT

Exactly, we want to have only one polygon for the overlapping area but with the information (attribute table) of all the overlapping polygons not to merge them but to join them.

Example: we have in the same shapefile one polygon with type of vegetation A and one with type of vegetation B and they have a common area.

Using union we have 4 new polygons. The not intersected area of the A polygon, the not intersected area of the B polygon, and one polygon of the common area with the attributes of A polygon and the same polygon with the attributes of the B polygon.

We want to delete the identical polygons but first we want to “copy” the information (at least) of the identical key in the attribute table.

At the end we want to have 3 polygons:

The not intersected area of the A polygon (A information in atribute table),
the not intersected area of the B polygon(B information in atribute table),
one polygon for the common area (A and B information in atribute table).

Re: Combine different keys in overlapping polygons

DavidPike — Thu, 09 Jul 2020 12:28:48 GMT

Spatial Join the intersection polygon with the original, use a Merge Rule of All to get both intersecting feature's info. Append this to your existing or Merge the datasets after the join.