# Intersect Tool returns 1 million *connected* rows - why does it not join them?

677
5
06-29-2011 05:54 AM
New Contributor
Hi All:

I have a layer with around 8000 polygons and and layer with 1 polyline - the intersect tools returns almost 1 million rows; however, most of those rows are connected (they have the same end XY and start XY and the source was the same polygon).

Is there any way to tell the intersect tool to combine rows that have the same end/start coordinates and are related to the same polygon there were created from?

Doug.
Tags (3)
5 Replies
New Contributor II
Try the "Identity" tool.  Sounds like that would work for you where you want the attributes of one feature class to be added to the other, or "joined" like you are saying.

Tyler
MVP Esteemed Contributor
Doug
I am assuming that the output is also a polyline since it is the lower geometry.  The intersect should produce a single segment for each traversal through a polygon so the section that traverses a particular polygon can be identified.  Are you saying that this is not the case?
New Contributor
Hi Dan:

Yes, I am saying that is not the case.

For example, one of the polygon intersects the polyline between XY #100 To XY #110 - the rows (shapes/polylines) returned for that polygon might be this:

Row #1:  XY #100 to XY #102
Row #2:  XY #102 to XY #104
Row #3:  XY #104 to XY #107
Row #4:  XY #107 to XY #110

OR

Row #1:  XY #100 to XY #102
Row #2:  XY #102 to XY #104
Row #3:  XY #104 to XY #106
Row #4:  XY #108 to XY #1010

In the first example, I would expect one row to be returned:

Row #1:  XY #100 to XY #110

In the second example, I would expect two rows to be returned:

Row #1:  XY #100 to XY #106
Row #2:  XY #108 to XY #110

Also, I thought perhaps cluster_tolerance may have something to do with this (I did not add a value for this)?
However, if I add a value to that parameter of the tool it throws an error (HRESULT -2147467259 - Unspecified Error).
I might be adding the value incorrectly - I tried this:

tool.cluster_tolerance = 1.5

Is this right or how do I add a this correctly?

Doug.
MVP Esteemed Contributor
a labelled screen grab demonstrating the above would help dissect what is going on
New Contributor
Hi Dan:

I only have ArcGISEngine EDN so to make a labelled screen grab I would first have to add labels to the map in code.  I don't know how to do that so I've been going the help file but can't find anything on adding labels to a layer.  I figure it must be some sort of layer renderer class for a feature layer but I can't find anything - do you know how to add labels to a layer via code?

Doug.