Query vector data intersections

[JohnUrbano]

Hello All,

I am a student and I am trying to locate "at risk" harbors around Alaska from polluted drainage by mines via river inflow.  What I would like to do is quantify how many tributaries a specific river inflow represents.  They rivers are nothing more than lines in a .shp file so how can I how analyze this?  Is there a way to query the number of intersections between endpoints of one tributary and the line of another?

Regards,
John

[DanPatterson_Retired]

If the two are indeed separate files, then perform an intersect analysis which will yield your intersection points if the segments do indeed cross as shown in the examples for line-line intersection.  This will at least give you the starting point.  There are alternatives involving code, however, I think this approach will enable you to use Select by Location, Spatial Join etc to obtain the associations and information between the resultant points and the crossing feature.

[SepheFox]

Hmmm, from his description I get the impression that it's just one shapefile. So how would you tackle that problem? I couldn't think of any easy way.

[DanPatterson_Retired]

Query the for the rivers, export to a shapefile....query for the line(s) of interest, export to shapefile, then intersect ....you can intersect a file with itself, then you have to query out from there...the former alternative is the cleanest and should take under a minumte