The Datum tab is used to specify the datum of the incoming GPS positions, as well as an optional GPS initialization string.


GPS Datum

Choose the datum of your GPS receiver. This is the datum your GPS receiver uses to display and output coordinates. It is not related to the projection of the current map. ArcPad does an onthe- fly projection between the geographic coordinates coming from your GPS receiver and the coordinates used in your current map. If the datum specified here is incorrect, you will get incorrect GPS coordinates in ArcPad. Most GPS receivers use WGS84 by default.

If the datum used by your GPS receiver is not listed here, you can add it to the defaulttransforms.dbf and transforms.dbf dBASE tables located in the System folder of the ArcPad installation folder. You can edit these dBASE tables using the ArcPad Datum Configuration tool or any third-party software that supports the dBASE format.

The ArcPad Datum Configuration tool can be used to change the default datums, change the datum transformation parameters, and add new datums and datum transformation parameters.

The default is WGS84 (D_WGS_1984).

GPS Initialization String

Text entered in this box will be sent to the GPS receiver upon activation. Use a circumflex (^) to indicate a carriage return, and a bar (|) to indicate a line feed.

This is typically used to enable or disable certain output options on your GPS receiver. It is not required to connect to your GPS receiver.

The default is blank.

Datum information

Tap NO ALT TEXT to view the datum parameters of the currently selected GPS Datum, including the parameters that ArcPad will use when transforming coordinates from the GPS datum to the datum of the map.