I'm using ArcMap 10.1. I had an orthophoto of an old study site. I traced two polygon shapefiles from this photo- one of "fields" and one of "forest". I made a point shapefile of the sampling points, and a polyline shapefile of all possible paths between the sample points. If a butterfly were to fly from one sample point to another (assuming linear flight along the polylines), I am looking to determine; a) what percent of that flight distance was through field, b) what percent of that flight distance was through forest and c) how many times that individual had to cross a forest/field edge.

I haven't used GIS since my intro class many years ago, and I can't even figure out the correct vocabulary to search for the answer myself. Any and all help is greatly appreciated! Even if you don't know how to do this, suggestions of what to search for are equally appreciated!

  • What types of butterflies? – Aaron Dec 12 '13 at 20:48
  • Aaron- Pieris napi oleracea (mustard whites) – user2196418 Dec 20 '13 at 16:54
  • Zachary- Thank you so much! This is exactly what I needed and it worked great! You have no idea how much of a headache you just saved me. – user2196418 Dec 20 '13 at 16:55

Here is one way to do it, it may get you started in the right direction:

  • add field to flight path shapefile named PathLength. Right click on new field and Calculate geometry
  • Merge your fields and forest shapefiles into one shapefile with a Type field designating each type
  • intersect flight path with new forest/fields shapefile
  • on the output line shapefile from the intersect task, add a new Segment length field and calculate length
  • Add new field to output line shapefile named percentage, calculate using field calculator as (seg length/PathLength)*100

The intersect job will have attached all of the attributes from the forest field shapefile, so each segment will now have whether it is in a forest or field and the percentage of the total length

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