topic Select polygons that are on one side of a polyline but not the other. in Data Management Questions

Select polygons that are on one side of a polyline but not the other.

JockMackenzie — Sat, 15 Jun 2013 04:35:05 GMT

How does one select polygons that are to the left side of a polyline.
I have 2 shoreline layers - (1970 & 2010). I need to know the shoreline gain and shoreline loss. So I created polygons of the areas where there is overlap - this gives me net change. But to identify which polygons are gain and which ones are loss depends on their relation to the 1970 shoreline. So I need to select polygons that are on the outisde (gain) and then those on the inside (loss). Is there a tool for this? E.g. I need to select only the red polygons in the diagram attached? Your help will be much appreciated.

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Re: Select polygons that are on one side of a polyline but not the other.

RichardFairhurst — Sat, 15 Jun 2013 05:54:43 GMT

Here are a few suggestions, which I found simply by searching the help for side of line.

About making a parallel copy of a line

Buffer - See the options for buffering one side of the line.

Make Route Event Layer (Linear Referencing) - See the offset_field and offset_direction field options

So basically create a parallel line or buffer on a known side of the line a short distance from the shoreline and use that to select the polygon features on a given side. If you use the buffer option make it slightly larger than you need and then select by location with a slightly negative buffer.

Re: Select polygons that are on one side of a polyline but not the other.

DanLee — Fri, 28 Jun 2013 21:08:15 GMT

I am just curious: Do you have the land-water polygons of the different years? If you do, the solution might be easier.