Document: How do I save data and map documents in ArcMap, what is the difference between them?

Created: 9/10/03 (Tom Evans)

This document describes issues related to ArcMap functionality related to saving edits to data and saving edits to documents. It also discusses file extensions that are associated with commonly used data files.

Working with Map Documents in ArcMap

ArcMap is the central tool in the ArcGIS software suite. In it you can view and query spatial data, or you can edit spatial datasets. It is important to understand the structure and functionality of ArcMap tools so that you are clear how to organize your work.

ArcMap can be thought of as a continous active session where you view and display data with various symbologies and at specific spatial extents.

You can save the settings in a current ArcMap session by using the File : Save or File : Save As tools from the main ArcMap menu. This saves the current ArcMap session and creates (or copies over) a *.mxd file (also called a Map Document file, analogous to a ArcView 3.x project file). The following items are saved when you save a *.mxd Map Document file:

• The spatial extent to which the Data Frame was zoomed
• Which features are present and turned on in the Table of Contents
• The symbology used to portray each feature in the Table of Contents
• Any Map Layouts, or maps that have been created via the View : Layout menu
• Pointers indicating the location on the filesystem for data elements in the Table of Contents

Saving the ArcMap session in a Map Document does not save any of the spatial data that is viewed in the Data Frame. It saves to the *.mxd document the settings and pointers to the data. Thus, if you copy a *.mxd file to another computer without also copying the data files separately and try to open the *.mxd file, ArcGIS will complain that it can't find the data that is part of the ArcMap Map Document.

To facilitate moving map documents and data between computers, follow these rules/guidelines:

• Keep your data within a single main top-level folder. You can then move this folder (and all it's contents between computers). This is easier than moving data files individually. A possible hierarchy/organization for a main top level folder is as follows:
  • Create a folder (e.g. mydata) on your zip disk
    • Within mydata folder you have a series of *.mxd files and a data directory
    • The data directory in the mydata folder contains data that the *.mxd files use
• Keep track of the drive letters that indicate the location on the filesystem where your data reside. When you use a zip disk, that zip disk is tied to a specific drive letter on your computer (and that drive letter may vary from computer to computer). Likewise when you Map a network drive to your CFS account, your CFS account is mapped to a specific drive letter. When you save your *.mxd map documents the Map Document remembers what driver letter was used for data in the Table of Contents. If you move a *.mxd file to another computer and try to open it, it will look for the data used by that Map Document at the same drive letter location as the computer where you last saved the *.mxd document. If you have your data at the same driver letter and with the same path then your *.mxd document will automatically find your data. If either the drive letter is different or the path under the driver letter is different, then you will have to manually tell ArcMap where the data are.
• Do not move spatial datafiles using Windows Explorer. Either move data files by moving the folder in which they reside, or use ArcCatalog

Editing and Saving Data in ArcMap

Edits to Data are saved in ArcMap by using the ArcEditor tool (can be toggled on and off by going to View : Toolbars : Editor). Once you bring up the Editor toolbar, you can begin an editing session by selecting Start Editing on the toolbar. You can then make edits to the spatial elements in a data layer in the table of contents (e.g. adding polygons, moving lines, deleting points). If you want to save the edits you've made you can either select Save Edits or Stop Editing and then specifying that you want to save your edits when the dialog box comes up. This alters whatever spatial dataset you are working on, for example a Geodatabase (*.mdb) or shapefile (*.shp).