A data dictionary is a "shopping list" of the features and feature attributes you want to map for your project. You create the data dictionary using Pathfinder Office prior to going into the field and download it to your GPS receiver. In the field, the data dictionary reminds you of what to record and the format of each record - as such it serves as a "protocol" for your project measurements (i.e. what is recorded and how it is recorded).

As an example, we will assume that the Campus Map project requires mapping of light towers, bike paths and parking lots on campus (as well as some additional point features that occur along bike paths and in parking lots - signs, fire hydrants, trees, etc.). In Pathfinder Office, open the data dictionary editor (Utilities|Data dictionary editor) - the following window appears (although the fields will be blank until you fill them in).

Figure 1. The Data Dictionary Editor Window.

After naming the dictionary (Campus Map in this example) and providing a comment (optional), you add a feature to be mapped by clicking on the New Feature button - this opens the following window:

Figure 2. New Feature Window.

Type in the name of the feature and then classify it as either point, line or area - in this example, the line feature "Bike Path" has been added to the dictionary. Once in the list, the feature can be selected and new attributes of the feature can be created. Clicking on the New Attribute button opens the following window. We will create the attribute "Width (meters)".

Figure 3. New Attribute Window.

The type of attribute is selected (numeric in this example). Then the New Numeric Attribute Window opens.

Figure 4. The New Numeric Attribute Window.

You must name the attribute, specify the number of decimal places, the minimum and maximum values and the default value, and specify if entry of this attribute is normal (optional), required or not permitted. Other attributes are created in similar fashion, for example the attribute Surface - a menu attribute is shown below:

Figure 5. The New Menu Attribute Window. The type of surface
is selected from a menu of choices (parking lot, grass, road, path, unused).

If you wish to record the date the feature was visited, a date attribute can be created, as shown below.

Figure 6. The New Date Attribute Window.

It is usual for the date to be automatically generated and for the field entry to be "not permitted" (to prevent the field crew from changing the automatically created date entry).

The finished data dictionary shows the list of features, the list of attributes for the selected feature and the list of entries for the selected attribute (Figure 1). Save the data dictionary in your project folder (File|save). Give the file a name and the extension ddf (for data dictionary file). It is often useful to print out the data dictionary (to take into the field, for example), to do this select File|print.

Figure 7. Part of the print out of the Campus.ddf file.
 

To transfer the data dictionary to the GeoExplorer, connect the GeoExplorer to the PC's com port and select Data Transfer on the GeoExplorer menu. In Pathfinder Office, select Utilities|Data Transfer, this opens the Data Transfer window shown below:

Figure 8. The Data Transfer Window.

The data dictionary is selected from the list of available files and added to the list of selected files. Highlighting a file in the selected files list and clicking on "Transfer" sends the data dictionary to the GeoExplorer.

(Note: the GeoExplorer can only hold one data dictionary at a time - pre-existing data dictionaries will be overwritten when a new dictionary is downloaded). You can review the data dictionary on the GeoExplorer by selecting Data Capture|Dictionary|Review on the menu.