The units of the length and area measurement reported by the Measure tool are the same as the X and Y units on your map. If the X and Y coordinates are in meters then the length is in meters and the area is in square meters.
If the map has a projected coordinate system assigned to it (i.e. not Lat/Long), you can change the units displayed in the Measure dialog by clicking Options | Units. Select the desired units and click OK. The measure results are immediately updated in the new units.
Click the Options button,
and click Units to set the units of the measure.
In the Units dialog, select the desired linear and area
units and click OK. The units in the Measure dialog are updated.
If your map does not have a projection defined, or it is in lat/long, then the units cannot be changed in the Measure dialog. To change the units, the units of the map can be changed by changing the coordinate system. Once the coordinate system has been changed, then the units in the Measure dialog will update the next time the command is used. It is useful to change the coordinates of the map if the desired length and area units are different than the map units.
For example, to change a map in lat/long to units of meters, follow these steps:
- In the Contents window select the Map object.
- In the Properties window select the Coordinate System tab.
- Click Change next to Coordinate System.
- In the Assign Coordinate System dialog, select the appropriate coordinate system. To convert the map units to meters, the coordinate system can be converted to a UTM coordinate system. The UTM coordinate systems can be found by navigating to Predefined | Projected Systems | UTM.
- Click OK. The map has been converted to UTM, which is in meters.
- Now if you click Map Tools | Map Tools | Measure and measure a line or area, the results will be in units of meters.
Updated October 14, 2021