How to calculate proportion of a line segment around a point?

Question

I am looking at certain variables surrounding points that represent Sea otter raft sites. The coast line surrounding the points is broken into unit lines (Essentially a polyline with attributes for various segments). For example, The unit lines have Oil Residency Index (ORI)(from 1 to 5) as well as a physical exposure proxy for each segment (segments range in length).

I want to calculate the proportion of different ORI and Exposure classes around each point (500m buffer). IE- What proportion of ORI class 1,2,3,4,5 are there around each point respectively.

I am using ArcGIS 10.2

Thoughts and ideas?

• jbchurchill: Why not just buffer the points (500m as you say) and then intersect the lines and summarize the length in each category for each point buffer?

Answer 1

I would create a ORIG_LENGTH field and calculate the original line length into it. Then I would buffer the points. Next I would use the Intersect tool. Finally I would use the Dissolve Tool to consolidate the lines based on their original line IDs and buffer IDs so that overlapping buffer cuts were eliminated. The final line length can be compared to the original length for a percentage. Other aggregations can be done if necessary once the Point Buffer ID and Line portions are intersected together.