Model Builder Iterator

Question

I split sections of a roads on a map using polygons and now I would like to dissolve the roads within those polygons, but I only want to dissolve rows that have the same road name. (Roads are lines).

I'm trying to use the ModelBuilder(arcgis 10.1) to iterate through all of the different polygons and take the different road names, and if both of these conditions are met, the roads would dissolve. This is what I have so far (MACK is the name of a polygon), and it just runs as a constant loop, so I don't think it's right.] Dissolve parameters.

Answer 1

You have to define a dynamic name for the output of the Dissolve tool, otherwise it will be overwritten each time the iterator processes a polygon feature class. 'Name' is the name of each feature class being iterated, you can use it by naming the output something like C:\Users\...\Default.gdb\MACK_%Name%.

See the 'Note' section of the help page A quick tour of using iterators for more details.

For the rest your model looks OK.

Answer 2

Well, assuming your polygons have some unique identifier, be that a GridID, unique feature ID, or even GlobalID, probably one of the easiest methods would be to use any of several available methods (I'd recommend ideally merging all the polygons together into one FC and then spatially joining that polygon FC to the split roads), to transfer the unique ID of the polygon each road segment is in to the road. Then you could simply run the dissolve once, using both the road name and the unique polygon ID fields as the dissolve fields, instead of having to deal with the iterator and tons of separate files. (Unless of course you really want each set in separate feature classes)