When using a map, you can measure a linear distance or an area (and its perimeter) using the Measurement tool. Map Viewer calculates the shortest measurement (using the ellipsoid-based geodesic calculation) even if the data uses a projected coordinate system. You can change the default units by updating your profile. You can also change the units of measure while performing a measurement.
Make a measurement
To measure distance or area, do the following:
- Open the map in Map Viewer.
- On the Settings (light) toolbar,
click Map tools
and choose Measurement 
.The measurement toolbar appears on the map.
- On the measurement toolbar, choose a measurement option as follows:
- Measure distance
—Measure a linear distance. Click the map where you want to start the measurement, and click once for every vertex of the line you want to measure. Double-click to complete the line. - Measure area
—Measure an area and its perimeter. Click the map where you want to start the measurement, and click once for every vertex of the area you want to measure. Double-click to complete the area.
The results appear at the bottom of the measurement window.
- Measure distance
- Optionally, do any of the following:
- From the Unit drop-down menu, select a different unit of measure. The measurement results are converted to the newly selected unit.
- Click Clear measurement
to clear the measurement. - Click New measurement to start another measurement.
Move the map while measuring
You may find that what you want to measure is not completely contained within the current extent of the map; for example, a street or parcel may extend beyond what is visible. To move the map as you're measuring, while maintaining the cumulative total distance or area, press the mouse button (or the equivalent navigation) while dragging the map in the desired direction. Double-click to complete the measurement.