Setting map units

Map units are the units in which the coordinates of the spatial datarepresented in your view are stored. ArcView uses the map units setting to determine the correct scale of your view.

The default Map Units are unknown. If you don't know the Map Units for the data in the view, you can leave the setting as unknown. Otherwise you should set them.

To set a view's map units

1. From the View menu choose Properties. The View Properties dialog box will be displayed.

2. From the Map Units list, choose the units you wish to use.

3. Press OK.


Most, but not all, "ARC/INFO coverages" and "ARC/INFO grids" contain an ASCII file with filename suffix .prj that describes the coordinate system used by that data set. You can look at this file to find out what map units your data are currently stored in. For example, if the Units in this file are listed as DD, the map units are decimal degrees.

If Map Units are not set correctly, the scale ArcView displays for your view may be incorrect, and ArcView won't know how large to draw your view if you specify a map scale directly.

A view's map units setting is independent of its distance units setting.

A view's map units setting determines whether or not you can choose a specific map projection for the view to be displayed in.