Buffer Tool Not Functioning as Expected

[JustinJohnston]

I have used the Buffer tool many times in the past without issue.  Today I ran the tool to add a 7-foot buffer to a polyline and the result is perplexing me.  The resulting buffer seems to be randomly offset from the line instead of being centered on it.  See screenshot for one such location. Instead of the buffer being centered, there is only 4.2' on one side and 9.8' on the other.  In other areas, it is nearly centered, but not quite.  I tried both the Buffer tool and the Pairwise Buffer tool with the same result.  Is this a bug from updating to 3.0?

[DanLee]

One possible reason is that your input lines and resulting buffer polygons are not in the same coordinate system.  Right-click the layers and select Properties - Source - Spatial Reference.

[DanPatterson · Accepted solution]

what is the coordinate system of the map and the polyline?

If it is web mercator, open a new map, with no basemap etc and set the map's coordinate system to a better projected coordinate system (like UTM, state plane etc), add the polyline and buffer it and see if the results look normal.  Web mercator shouldn't be used for anything other than "looking".  Operations that involve distance and area are not well suited to it.

[JustinJohnston]

I checked coordinate system of the line and it was WGS1984.  I used feature class to geodatabase to make one in state plane.  Used that new line to run the buffer tool.  Now it works as expected.

Thank you!

Cheers,

Justin

[DanLee]

This is always the best practice. 🙂