topic Re: sum of overlapping polylines in Spatial Statistics Questions

sum of overlapping polylines

JessicaLeonard — Mon, 26 Nov 2012 18:59:17 GMT

I am looking to calculate the sum of overlapping polylines in a field. I have fish distribution data and I would like to create a richness field to calculate the number of species on each stream segment.

I have previously converted all of the polylines to rasters and used the weighted sum tool, however, I would like the richness number stored back in a merged shapefile. The final result will be a web mapping application and the pixelated raster on the web is less than aesthetically appealing.

Any suggestions would be greatly appreciated,
Jessica

Re: sum of overlapping polylines

DaleHoneycutt — Tue, 27 Nov 2012 02:22:51 GMT

Do you have polylines of each species? I'm guessing that these polylines overlap each other. It seems like you should be able to use the Intersect tool.

Perhaps you can provide a small sample dataset?

Re: sum of overlapping polylines

JessicaLeonard — Thu, 29 Nov 2012 20:09:55 GMT

It seems tedious to use the intersect tool, as you would have to run the tool for every possible combination which would amount well over 30 times. I really just want a species richness count. Weighted overlay does it very well for rasters, but I would like the number tied back to the polyline for web viewing.

Re: sum of overlapping polylines

DaleHoneycutt — Thu, 29 Nov 2012 20:13:11 GMT

If your species are in separate feature classes, just run Intersect once, feeding it the separate feature classes. If you have but one feature class containing all the species, just run Intersect on that one feature class.

If you have some data you'd could let me play with, zip it up and email it to arcgisteamanalysis@esri.com. I've been playing with some made-up data... it looks like an Identity (not Intersect) is what you need... but w/o specific data, it's hard to say. In any case, this is not a straight-forward problem, so I'd like to help you solve it.