[GIS] How to change/identify Linear units in Near Analysis Attributes Table

arcgis-10.1arcgis-desktoplinear-referencing

I need to get the closest distance from multiple points of a multipoint feature to a polyline that delineates a land contour. To do this, I used the Near(analysis) feature. It worked, but I can't tell what units it has produced. I right clicked on the layer, but it doesn't have a Linear Units category under the Source Tab of Properties. Also opened up a .prj of the layer to see what the units are -also unspecified. Checked the dataframe properties and it said my Linear Units are in meters (which is what I want them to be in), but that is not correct given the measurements the Near tool produced.

Any suggestions for how to calculate the distance in meters OR change whatever units are in the NEAR_DIST column of my attributes table?

Best Answer

I recommend reading How proximity tools calculate distance from the ESRI help pages. The units will be whatever your input spatial reference is in (e.g. NAD 83 UTM 12 N will be in meters). Make sure your data are in an equidistance projected coordinate system with the units you would like in the near output. If your data are in a geographic coordinate system, you will likely see near values that are inaccurate.

Distance measurements will be most accurate when your input data is in an equidistance projected coordinate system. While distance calculations can always be performed regardless of coordinate system, the results may be inaccurate or even meaningless when your data is in a geographic coordinate system or an improperly selected projected coordinate system.

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