Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
I am aware that this question has been asked here: Removing unnecessary vertices?.
I want to focus a different point. How to remove unnecessary vertices without changing the shape at all. As you can see in the example below I want to get rid of vertex 2 and 3. All generalize or smooth functions I saw so far, will somehow alter the shape of the polygon/polyline. So they will mess with vertex 5,6 and 7 in the example.
I can only speak for ArcGIS, but since you didn't mention any specific software, here's my answer.
The Simplify Polygon tool with the POINT_REMOVE option should do what you want. From the help:
POINT_REMOVE—Keeps the so-called critical points that depict the essential shape of a polygon and removes all other points
Have a look at this page. Follow the instructions, you can select multiple polygons by drawing a box around them with the tool and then run the generalize edge tool.
Here is a polygon with "extra" vertices:
After running the Generalize edge tool and fiddling around with the tolerance scroll bar I created this:
Your question gives no indication of the scale of your data, are they houses or national parks? I ask that as the tolerance may not be appropriate for all of your polygons, but you can certain do batches of them. You can see the effect of the tolerance if you have preview ticked on, useful before committing to the generalization.
