Distances: units and why different from manual

[Mikhail]

I use 'Generate near table' to measure distances from a set of points to a point of interest. I got my results, but the distances came in some odd units. To resolve this issue, I manually measured the distances for 10 randomly selected points. The outcome was that my 'unit' equals approx. 131 km - I wonder what unit it could be. Even more worryingly, whilst 131 was the average multiplier, it differed point-by-point from 111 to 171 which is quite a lot. Why could this be? Has anyone met with a similar problem? Thank you.

[DanPatterson · Accepted solution]

distances are in the units of the coordinates of the data.  If the units are "strange" there is a good chance that your data are in decimal degrees and your distances are in decimal degrees.

From Generate Near Table (Analysis)—ArcGIS Pro | Documentation

They suggest to use an appropriate projected data set prior to calculating the distances (ie use the Project tool)

[Mikhail]

Got it, thank you so much! On my map the system was set to Web Mercator, I changed it to British National Grid...and got the same 'strange' units again. What am I doing wrong?

[Mikhail]

Sorry, I kept trying and know the answer now. Had to set the method to geodesic. Thank you again for your help!