Inserting the scale bar with USGS topographic basemap clearly shows the map scale is more than twice what is expected. Measure a section (square mile) with the measure tool yields nearly 3000 acres when it should only by 640. Similarly measuring the square miles of a single section should be only 1 square mile but measure tool gives 4. An inserted scale bar is also off by a similar factor. Any suggestions on why ArcMap 10.2.2 is miscalculating?
Is the coordinate system on your data frame consistent with the the datasets your layers point to? Are you displaying data, for example, in an inappropriate projection (ie trying to use UTM Zone 18 in Massachusetts).
What part of the world are you displaying? This projection is awful in polar regions.
WGS_1984_Web_Mercator_Auxiliary_SphereProjection: Mercator_Auxiliary_SphereLinear Unit: Meter (1.0)
Trying to measure acreage, but I check different units using both line and polygon switching from meters to miles, etc. all appear to be consistently off. All other layers, including waypoints, tracks, and trails overlay correctly on Basemap. Grid coordinates appear accurate as well. Only scale and measure tools appear off.
Units under Data Frame Properties are:
Map: Meters (seemed to be locked in, can't change it)
Display: Decimal Degrees
Reference Scale: Use Current
What's the spatial reference of your map? If you want to measure meters it should be a projected coordinate system (like UTM). Also check the data frame properties / General tab to see how the distance units are set.
check units... don't assume they are in feet, especially if you didn't download directly from the site and check metadata to confirm. Also confirm that the units are indeed planar and not in decimal degrees, regardless of what your dataframe is set to.
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