A quick guide to ArcPad customization files

ArcPad XML files (*.apx)

Although all of the ArcPad customization files are stored as XML text files, the .apx file extension is only used for the following files:

Other ArcPad XML files include ArcPad Graphics Layer (*.apg), ArcPad Photo Layer (*.aph), and ArcPad Stylesheets (*.aps). For more information about these files, see Supported vector data.

ArcPad applet files (*.apa)

Applets provide a way of delivering a mini-application in a single file without altering the ArcPad configuration. Applets may contain toolbars, forms, and system object-event handlers.

Applets are loaded automatically by ArcPad after the default configuration has been loaded. Applet files are located in the Applets Files Path, which is specified in the Paths tab of the ArcPad Options dialog box.

If you have multiple applets, the order they are loaded into ArcPad is dependant on Windows file system management rules. ArcPad loads files in the reverse file system order. For example, this is important to users who have multiple applets—that each contributes a tool to a common toolbar. The order that the tools appear on the toolbar will be the reverse order in which the applet files are read from Windows.


File ordering is different in different file systems. In an NTFS file system, file ordering is alphanumeric. In a FAT file system, file ordering is dependent on the order files are copied (or created) in a folder.

For example, if you create the files Bravo.apa, Alpha.apa, Charlie.apa (in this order) on a machine with a FAT file system, the default file order will be Bravo.apa, Alpha.apa, Charlie.apa (that is, exactly as you created the files). The NTFS default order for these very same files would be Alpha.apa, Bravo.apa, Charlie.apa (that is, ascending alphabetical order).

ArcPad will always load files in the reverse file order. So, on a FAT file system, ArcPad will load the files described above, in the order of Charlie.apa, Alpha.apa, Bravo.apa (that is, reverse creation order), and on a NTFS file system, ArcPad will load the files Charlie.apa, Bravo.apa, Alpha.apa (that is, reverse alphabetical order).

ArcPad layer definition files (*.apl)

Layer definitions are stored in the ArcPad AXF file, or in a file associated with a shapefile, with the same file name as the shapefile but with the extension .apl. Layer definition files provide a way of developing customizations that are delivered and loaded with data. Most customizations delivered in this way are data entry forms with associated scripts that handle data-entry validation and other features offered from the forms. Layer definition files can also contain custom symbology exported from ArcGIS Desktop.

ArcPad map files (*.apm)

An ArcPad map file stores a list of the map layers of your ArcPad session. A map lists all of your feature layers together with their display settings including the extent of your map, color, and projection environment.

VBScript (*.vbs) and JScript (*.js) files

Much of the customization in ArcPad is accomplished by writing scripts. Currently, ArcPad supports Microsoft’s VBScript and JScript scripting languages. Although scripts may be embedded within the various ArcPad customization files, it is often more efficient to place related scripts in a separate text file with a .vbs or a .js extension.