Introduction:
It is assumed that mapping is conducted with a data dictionary. It is possible to collect positions without using a data dictionary, but features (points, lines and areas) can not be specified and attribute data can not be collected - mapping without a data dictionary is not recommended. It is also assumed that the section on GeoExplorer Configuration has been reviewed. Under normal circumstances most data dictionaries would contain point, line and area features - mapping of each kind of feature is treated separately here (note: some procedures are common to mapping of points, lines and areas, so some duplication appears in the mapping guides). It would also be usual for a single mapping project to use several rover files; for example, mapping could be temporarily halted for a lunch break or because PDOP values are too high - in these circumstances the rover file would be closed and a new file opened after the break - closing the rover file also enables the GeoExplorer to be turned off to conserve the battery.

Field Procedures: Point Features

Checking GPS Status
Hold the GeoExplorer level, so that the antenna (under the Trimble logo) has a clear view of the sky (anything that blocks light can block the satellite signals, so try to stand in the open, as much as possible). After switching on the GeoExplorer you will see the main menu. Once the GPS is turned on, it can take from 5 to 15 minutes to locate satellites, lock onto them and begin calculating positions. To view the progress the GeoExplorer is making in acquiring satellites, select GPS Status from the main menu, then select Sat Tracking. The Satellite Tracking screen appears.

Figure 1. The Satellite Tracking Screen.

This screen shows you which satellites are being tracked; a small arrow in front of the satellite number (PRN) shows that it is being used to calculate position. The PDOP (position dilution of precision) value is also shown. When the minimum number* of satellites is acquired and the PDOP is below the maximum specified value*, the GPS should start calculating positions (*based on the GeoExplorer configuration).

Press ESC to go back to GPS Status, then press ESC again to get back to Main Menu, select Position; if "GPS Position" appears at the top of the screen, it means the GeoExplorer is calculating positions and you are ready to map (if "Old Position" appears at the top of the screen, it means the GeoExplorer is not calculating new positions - check Sat Tracking and cable connection).

Figure 2. Position Screen - "GPS Position" indicates
that the GeoExplorer is Calculating Positions.

Opening A Rover File
Position yourself at the first point to be mapped (in this case, "tree" will be used as an example), select Data Capture, then select Open Rov. File.

Figure 3. The Data Capture Screen.

A rover file* is opened and named automatically as follows (*rover file refers to a file that records field data):
File prefix (for example, C)
Month (for example, 06 - June)
Day (for example, 25)
Hour (for example, 09)
A - the first file created in the 9th hour of June 25th.

C062509A would be the file number (C062509B would be the 2nd file created in the same hour). Usually the receiver would begin recording positions to the file as soon as it is opened (see GeoExplorer configuration).

Selecting A feature
Once the rover file is opened, a list of options appears; choosing the option select feature brings up the list of features in the data dictionary:

Figure 4. The Select Feature Screen.

When the required point feature is selected (for example, tree), that feature is "opened", meaning that positions for the feature begin to be recorded. The number of positions collected is shown at the top right of the receiver screen.

Entering Attribute Data
Selecting a feature also brings up a list of attributes for that feature. Attribute data can be entered while the receiver is recording positions for the point feature. Use the up-arrow or down-arrow to scroll to the desired attribute; selecting the attribute allows values to be entered. For example, selecting the menu attribute "Condition" might bring up the list of menu items "Excellent", "Good", and "Poor" - one of which could then be selected; selecting the numeric attribute "Height" allows you to enter a numeric value (use the left-arrow and right-arrow to move between units, tens, hundreds etc. Use the up-arrow and down-arrow to change digits - when the number is correct, use the selection button to enter the value. The same technique is used to enter characters in text fields).

Closing The Rover File
When you have collected enough positions for the point feature (usually 120 - see GeoExplorer configuration), selecting close feature closes the feature and returns you to the select feature screen (Figure 5). You can then move to the next point to be mapped and repeat the process (Note: if you have enough positions collected for a feature, but you need more time to record attribute data, you can select Pause to temporarily halt recording of positions - when you are ready, selecting Resume begins recording again). When all required features have been mapped, selecting close file closes the file.