What is the most efficient method for selecting a subset of mutual polygon boundaries bsaed on properties of the polygon shape file?

[WalterWitt]

I use ArcGIS 9.3.1 and want to select a subset of mutual polygon boundaries from a geology shape file. The selection will be based on the Rock Name properties of the polygons.

[JayantaPoddar]

I would start with Union—Help | ArcGIS for Desktop .

This will give me all the features and attributes.

Then, I would put a Definition Query (Layer Properties of the Union output) where

"Rock_Type1" IS NOT NULL AND ("Rock_Type1" = "Rock_Type2")

where Rock_Type1 and Rock_Type2 are the Rock_Type fields of Feature 1 and 2 respectively.

You could export the layer to a feature class, if desired.

[WalterWitt]

I am not ure that I have understood you correctly. I have just now tried that Union command on the geology shape file, Jayanta. However, the product file is still comprised only of polygons and I want to select the boundaries between certain polygons

[JayantaPoddar]

Are the polygons residing in a single shapefile or different shapefiles?

[WalterWitt]

Jayanta, the polygons are all within one shapefile

[DanPatterson_Retired]

The selection will be polygons since union doesn't downgrade like geometries like intersect does. 

[FC_Basson]

Maybe the Polygon Neighbors tool can be of assistance: Polygon Neighbors—Help | ArcGIS for Desktop 

[DanPatterson_Retired]

hmmm if someone could experiment with an intersect and the output of the Polygon Neighbors that would be a useful pair

[WalterWitt]

My version of Arc (9.3.1) does not offer Polygon Neighbours (at least I can't find it)

[FC_Basson]

Yes that tool is not available in 9.3.1.  Maybe you should look at a method of iterating (with Python) through your polygons and selecting the polygons that touch boundaries, based on the rock type attribute selection, and in the process you can write all adjacent polygon attributes to a new field.  Can you be more descriptive of what you want to achieve?