Buffer distance inconsistency

Question

Hello,

I am using ArcGIS version 3.3 and have encountered an issue. I created a 0.5-mile buffer around a point, but when I use the "Measure Distance" tool to check the distance, it shows 0.68 miles. My layer is projected in State Plane NAD1983 FIPS 2001. Could you please advise on how to resolve this discrepancy? Any assistance would be greatly appreciated.

Best,

Yesim

YesimSungu-Eryilmaz · Answer

Thank you! I changed the map's coordinate system to State plane as it was set to WGS84 and that solved the problem.

YesimSungu-Eryilmaz · Answer

I changed the map's coordinate system to State plane as it was set to WGS84 and that solved the problem.

ChristopherCounsell · Answer

When running the buffer tool it will respect the output coordinate system and any transformations.

https://pro.arcgis.com/en/pro-app/latest/tool-reference/analysis/buffer.htm#GUID-E3EA0491-1E80-418B-A884-626F979DC934

This means that the buffer may run and generate in the desired coordinate system (0.5 miles).

But the map may be measuring in the map coordinate system e.g. WGS84 web mercator would throw a different measurement.

As Dan Patterson hinted at, adding the layer to a new map will default to the layer's coordinate system and show the measurements in that.

But one other thing to consider is that you can do planar or geodesic buffers. By default the planar method will be used. Double check what mode is being used in your map when using the measure tool.

https://pro.arcgis.com/en/pro-app/latest/help/mapping/navigation/measure.htm#ESRI_SECTION1_AA3FBCB332934D84993C6EE58ACB6BBC