I was preparing a polygon dataset to work on an ArcGIS Pro tutorial the other night and I needed to reshape polygons. The feature class I started with contained polygons of California state census divisions. I wanted to change the boundaries of census divisions so that I had some different shapes. Now this isn’t too hard to do, but I wanted to change the shape of one polygon and at the same time change the shape of the bounding polygon to match it. Luckily it turned out that this was a very easy workflow to accomplish in ArcGIS Pro, so I decided to write a quick blog post about it.
Overall they have made it a lot easier to edit feature classes in ArcGIS Pro compared to ArcGIS Desktop. Which I am quite thankful for, it has really allowed me to speed up the editing process. To get started editing select the layer you want to edit in the Contents pane. Then go to the Edit tab and select Modify.
Now the Modify Features pane will pop up. The tool we are going to use is the Reshape Tool, under Reshape Tools.
Now the Reshape dialogue will load up. In order to reshape a polygon you need to have at least two selected. Once you have some polygons selected it will show you their ID and show the reshape button.
Once you have pressed the reshape polygon you can start to draw your new polygon. The polygon which you start add the first point will be the polygon that is expanding. The second polygon that you enter will be the one which has its area removed. Draw the polygon as you desire and finish off by double clicking. Below are a series of images showing me expanding one polygon into another and then vice versa.
Start with the polygon you want to grow and draw the new shape.
The first polygon has expanded into the second polygon.
Showing the tool again this time starting from the polygon on the right.
The polygon on the right has the new area inside of the polygon on the left.
Once you are done modifying the polygons press the Finish (F2) button on the floating editing pane.
There you have it! We used ArcGIS Pro and the Edit>Modify Features Pane to reshape polygons. After selecting the two polygons we want to modify draw the new boundaries and the first polygon you edit expands into the second. The second polygon decreases space proportionally and the boundaries of both polygons remain the same. What a quick and easy editing workflow. This would be very handy if you are doing geological field mapping and have to redefine the boundaries of rock units. This method will not generate any empty space or introduce slivers.