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.
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.
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
Are the polygons residing in a single shapefile or different shapefiles?
Jayanta, the polygons are all within one shapefile
The selection will be polygons since union doesn't downgrade like geometries like intersect does.
Maybe the Polygon Neighbors tool can be of assistance: Polygon Neighbors—Help | ArcGIS for Desktop
hmmm if someone could experiment with an intersect and the output of the Polygon Neighbors that would be a useful pair
My version of Arc (9.3.1) does not offer Polygon Neighbours (at least I can't find it)
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?
The selection will be based on the Rock Name properties of the polygons.
Would you like to explain it in more detail, maybe with an example?
Because you are still using 9.3.1, you may be able to find a tool in one of the older (free) 3rd party tool sets like Hawths Analysis Tools for ArcGIS Hawth's was used heavily for homerange and other analysis in the past, but for 10+ it was turned into an R base user interface...still using ArcGIS tools. You will need a Spatial Anlysis extension for many of the tools in the tollbox, but there may be a tool there that can do what you need.
There were several other popular 3rd party tools for 9.x including Xtools, although I'm not sure if you can still find the 9.x versions. I found a link for a 9.2 download, but not sure about the site it brought me too (not xtools-pro) so I'm not posting here.
No a direct answer to your question, but some options to look at.
Thanks for all your suggestions. I conclude that it is not easy to do what I want to do in ArcGIS. I do remember using an add on with Arc9.3.1 in another job. This add-on converted polygon shape files to line shape files, which may have been a useful start.
In the end, for the problem I asked about, I digitised the required contacts manually - thankfully, it was not a huge task, but it could have been with a different data set.
Anyway, thanks again. We can consider this discussion closed.
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