topic Re: How do I create a polygon that is inset a specific distance from another polygon? in ArcGIS Pro Questions

How do I create a polygon that is inset a specific distance from another polygon?

jlperkin — Wed, 27 Oct 2021 19:38:28 GMT

I am using ArcMap 10.7.1. I want to create a polygon that is inset a specific distance from another polygon. To make matters more complicated, I want those distances to be different. For example, using setback dimensions in feet from a property line, I would like to create a polygon that shows the "buildable footprint", 25 feet from the front, 50 feet from the rear, and 5 feet from each side. I believe I only have the basic version because the COGO toolbar is grayed out. Any help would be greatly appreciated.

Re: How do I create a polygon that is inset a specific distance from another polygon?

Robert_LeClair — Wed, 27 Oct 2021 20:50:18 GMT

One option to consider is the Trace tool in ArcMap. For your buildable footprint polygon, first create a new feature with a trace offset of 5' from the parcel edge to create the initial polygon where all 4 edges are offset equally 5 feet. Next for the front offset of 25 feet from the front, select the newly created polygon (if needed) and select the Reshape tool. Have your snapping on for vertex and edge. Start the reshape sketch by snapping to one of the front corners and move your mouse down a little bit. Right click on the existing buildable footprint line and select parallel. Then right click again, select length and type 25 ft. Click to place your vertex. Then move your mouse to the front of the buildable area, right click on the buildable footprint line and select parallel. Move your mouse to the other side of the polygon and click the set a vertex. Then F2 to finish the sketch. Repeat the process for the 50 feet from the rear. See images in this post.

Re: How do I create a polygon that is inset a specific distance from another polygon?

jlperkin — Thu, 28 Oct 2021 13:22:59 GMT

I was able to offset the buildable footprint from the property line 5 feet with tracing; however, I cannot figure out how to parallel trace when I reshape. The image shows my final result, which does not accurately reflect the 25 feet and 50 feet offset of the property boundaries. As far as I can tell, I am following your directions. I could not see your images as they are blurry. So if you detailed my question in your photos, I apologize, but I cannot see. I appreciate your help. Thank you.

Re: How do I create a polygon that is inset a specific distance from another polygon?

Robert_LeClair — Thu, 28 Oct 2021 13:58:52 GMT

Thank you for your response - not sure why my images are blurry as they are not so on my side when I review the response. Regardless, the next step does not do a parallel trace, rather I turn on snapping for vertex and edge first. In the image, you'll see numbers and arrows.

1. With the reshape tool selected, snap to a corner marked 1.
2. Move your mouse along the edge marked 2 and right click. Select parallel from the context menu.
3. Right-click again where you did in item 2 and select Length from the context menu. Type in 25 ft.
4. The sketch is constrained 25' - click to place a vertex on the line where the 3 (and arrow) is located.
5. Right click again on the item marked 4 and select parallel from the context menu.
6. Move your mouse to the item marked 5 and click once to place a vertex.
7. Click F2 on your keyboard to finish the sketch. The area to the left of the polygon will delete.

This should work for the first edge constrained 25'. Then repeat the process for the back line. Hope this helps!