Characteristics and Examples of Spatial Data - Introducing Geographic Information Systems with ArcGIS - page 127

Housekeeping: Saving and Restoring a Map
As you work it is a good idea to save your work. While you could easily reconstruct what you have done so
far, you have some time invested that you would rather not lose.
23. On the File menu, find and click Save. A Save As window appears. Navigate to
the ___IGIS-Arc_ YourInitials folder so that it appears in the Save In box. For a filename, which
currently reads Untitled.mxd, use River_Map. The Save As Type field should read ArcMap
Document. The file extension MXD designates the file as an ArcGIS Map document. See Figure
2-15. Click Save. Note that the title bar of the ArcMap window has changed to River_Map and that
the ArcMap button on the Windows taskbar also reflects that change when you mouse over it.
FIGURE 2-15
24. Dismiss ArcMap. Using the Windows operating system, look at the contents of the
folder ___IGIS-Arc_ YourInitials . Notice it contains the file River_Map.mxd. 15 How large, in
kilobytes, is the file? _________ KB. Pounce on River_Map.mxd. ArcMap will restart and load
the map you just saved.
It is vital that you understand what an MXD file is and what it is not. While it contains a great deal of
information about how the data it refers to is represented (symbols, colors, line widths, and so on), the
MXD file does not itself contain data . The MXD file contains pointers to the data—that is, the map file
tells ArcMap the names of the folders where the datasets are located. You could not, for example, send
only an MXD file to a colleague and expect her or him to be able to see the map with only ArcGIS desktop.
You would also have to send any relevant geodatabases, shapefiles, and coverages. (You could, however,
send a Layer Package—to be discussed later.)
15 If the extension name “mxd” doesn't appear after the name River_Map, find out how, with Windows, to turn off the
checkbox in front of “Hide extensions for known file types.”