I am looking to extend the polygon feature to the to the coastline polyline (blue line) while keeping the attributes of the polygon features (Figure below). enter image description here

What I am looking to do is find the percent ownership (public vs. private lands) along per coastline mile (i.e. I only care about the right-most parcels of the polygon. And I do have these separated out). A simple buffer does not retain attributes for me to know the ownership of the adjacent parcel to the left of the coastline. Also since the coastline meanders an intersect does not capture all the parcels.

In one attempt, I converted the polygon to a raster, so that I could use the "Expand" tool to extend out to the line. But when I did so, the expansion seemed to run off at a 45 degree angle (Figure below), which does not capture the true length of the polygon parcels. enter image description here

An example output of what I am looking for is below. enter image description here This is a section where the original coastline line crossed the parcels and an "Intersect" was done. This new intersect polyline is symbolized by color (e.g. green = public). With this, the length of each segment can be totaled for the entire coast and used to determine percent ownership.

Any ideas on how to keep the raster expansion bounded to the parcel dimensions, or other ways about going at this will be extremely helpful! These images are a subset of one county - and I am looking to do this for 14 others. Using Arc 10.4.

  • How many polygons are you wanting to extend? Also what gis system are you using?
    – Hornbydd
    Dec 28, 2016 at 17:35
  • For this particular county, there are 586 parcels that are "coastal", meaning they are the right-most parcels (all within the same polygon currently). However this is just one county of the 15 that I am looking to do.
    – user88758
    Dec 28, 2016 at 17:42
  • Just needed to establish if you could do this manually or require some sort of automated approach. It is good practise when asking a question to give us an idea of how much processing is required rather than just stating the problem.
    – Hornbydd
    Dec 28, 2016 at 18:39
  • Could you amend you question with an image of the desired output?
    – Hornbydd
    Dec 28, 2016 at 18:44
  • Place points on coastline at a very small interval apart. Find nearest parcel to each. The ratio you are after =countOfPublic/countOfPrivate.
    – FelixIP
    Dec 28, 2016 at 18:57

1 Answer 1


As commented by @FelixIP:

Place points on coastline at a very small interval apart. Find nearest parcel to each. The ratio you are after = countOfPublic/countOfPrivate.


It will give the length = countofpoints*intervalbetweenpoints. The smaller interval the more accurate estimate.

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