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An Introduction to GPS
Application #1: Marking and Saving Waypoints
Waypoints enable you to mark and record your current location as a waypoint. A waypoint is a
“virtual” location marker. Once a waypoint is established and saved, you can easily navigate back to
the waypoint using the GPS. This can be helpful to locate research plots in a large stand, identify and
relocate potential pollution sources, or to identify and mark specific areas with in an area that have
been impacted by blight or disease (that you may want to return to at a later date). It is also possible
to upload Waypoints to a desktop computer (using DNR Garmin or GPS Utility or similar software
To mark and save your current location as a waypoint:
1. Walk to the point where you want to obtain a waypoint (a location on
a stand experiencing drainage problems, an area with in an orchard
that may require additional attention, etc.).
2. Press down and hold the Click-Stick until the Mark Waypoint Page
appears (See Figure 5).
3. This GPS automatically assigns 3 digit numbers to waypoints (in this
example, it assigned 001 as the waypoint name). You can customize
the name of the waypoint. To change the name of the Waypoint, use
the Click-Stick to highlight the waypoint name field (in Figure 5, the
name field is 001).
4. Type the new name for the waypoint, using the Click-Stick to select
and enter the characters from the on-screen keyboard and select OK
5. You can also change the marker symbol associated with the waypoint
by selecting the marker (with the Click-Stick) and scrolling through
the different options (Figure 7).
6. Use the Click-Stick to scroll down to the OK button, and select the
OK button to save the Waypoint.
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The Virginia Geospatial Extension Program
Application #2: Finding (navigating to) a Waypoint
Your GPS can serve as an “automatic pilot” to navigate you back to a previously defined Waypoint!
To navigate back to a previously defined waypoint, follow these steps…
1. Press and hold the MENU/FIND button on the left side of the GPS receiver (Figure 1)
2. On the FIND menu, select Waypoints using the Click-Stick (Figure 8)
3. Use the Click-Stick to select the desired waypoint from the list (Waypoints are typically
4. Select the „Go To‟ option to create a direct line of travel to the Waypoint (Figure 9).
The map page is the default navigation page (Figure 10). At the top of the page there will be naviga-
tional directions. These directions will indicate a cardinal direction that will take you to your destina-
To use the Compass Page for navigation (Figure 11), hit the Page Button and go to the Compass
Page. The arrow in the center of the compass serves as the bearing pointer, which directs you to the
destination waypoint. The navigation page also informs you that you are 0.14 miles from the way-
point. At your current speed (0 miles/hour), you will reach the next destination in approximately 4
seconds and 4 seconds.
To stop navigating press the Menu button and select Stop navigation.
Figure 8 Figure 9 Figure 10
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An Introduction to GPS
Application #3: Finding (navigating to) a Waypoint that
was defined by someone else
You may need to navigate to a Waypoint that was defined by someone else (i.e.. a landowner or
other constituent, a county official, a fellow extension agent or fellow extension specialist). This
person may have used a different GPS receiver (or even model) and may therefore provide you with
coordinate information (or, you can also obtaining coordinate information off of a Geographic In-
formation System or other map).
Obviously, your GPS receiver can not navigate you to a coordinate pair (i.e. lat./ long, UTM, etc.) if
the coordinates are not stored on your GPS receiver as a waypoint. However, you can create a way-
point by manually entering coordinate information (i.e. lat/long., UTM, etc.) into the GPS re-
To create a waypoint by manually by entering its coordinates, follow these
1. Press in and hold the Click-stick to access the Mark Waypoint Page
2. Using the Click-stick, highlight the Location Field on the Mark Way-
point Page (Figure 12).
3. Enter the new coordinates using the numerical keyboard on the
screen. Highlight and press „OK‟ when finished.
Important Tip: In the United States, the first (latitudinal) coordinate will always have a “N” as a
prefix (as we are north of the equator). The second (longitudinal) coordinate will always have a
“W” as a prefix (as we are west of the prime meridian). In addition, the first digit after the “W”
should be entered as a “zero” (see illustration above). It is very important to identify and select
these prefixes when manually entering waypoints on your GPS!
4. Once the Waypoint coordinates have been manually entered and saved, you can then use the
„Go To’ or FIND function (see previous page) to navigate to that waypoint!
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The Virginia Geospatial Extension Program
Application #4: Estimating Area Measurements
Estimating area measurements in the field is a necessary task for many application areas of extension
including business planning, forestry, and natural resource management. This GPS receiver has the
capability to estimate area measurements, even of curved and irregularly shaped polygons! The fol-
lowing procedure will not only generate area measurements, but will also provide perimeter meas-
urements as well.
There are two techniques for estimating area measurements. These techniques include:
The Track Log Method
The Route Method
While the Track Log Method is used most often, both of these techniques are easy to learn, and are
described in this section.
Estimating Area Measurements: The Track Log Method (Option #1)
As you travel the perimeter of an area, the eTrex Venture HC records track
points and uses the resulting GPS track log to internally calculate the size of
the enclosed tract. This method works well when you can reasonably trans-
port the receiver directly along the boundary of the tract. [If swamps, lakes,
cliffs, gorges, or grizzly bears get in your way, you may need to use the
route technique as an alternative!]. The active track log can hold up to
On small and irregularly shaped tracts of land, you might want to increase
the track log interval - the frequency at which tracks points are recorded.
Otherwise, you will lose accuracy when the receiver occasionally “cuts
corners” as you travel the boundary. Go to: MAIN MENU > TRACKS >
highlight & select Setup. The Track Log Setup page (Figure 13) will open, you have choices here.
The default setting is Record Method: Auto (a combination of distance and time) and Interval: Nor-
mal. If you choose to keep the Auto setting, you can set the Interval to More Often or Most Often to
increase the frequency of track points. Instead of Auto, you can choose to re-
cord by Distance or Time, each with its own Interval choices.
Follow these steps to estimate area measurements:
1. Generally you should clear the current active track log just before you be-
gin laying tracks. Go to: MAIN MENU > TRACKS > CLEAR. [If you
wish to save the previous track log, first select SAVE, then clear the log].
2. Push the Page button until you reach the Main Menu Page (Figure 13). Figure 14
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An Introduction to GPS
4. Use the Click-stick to scroll down and highlight the Tracks option.
5. Press the Menu button and select Area Calculation. The Area Calcula-
tion page should open (Figure 15).
6. The Area Calculation page will look very similar to the Map Page, BUT
will have a Start option at the bottom (see Figure 16).
7. You may need to reset the Area Calculation. This is done by hitting
the Menu button and selecting the RESET option.
8. Press and begin walking around the perimeter of the field/
parking lot / forest plot / etc. that you want to calculate an area calcula-
tion. The screen displays your progress. Zoom in or out as appropriate
to view your tracks.
9. Slightly before you return to your starting point, click on STOP. Your
receiver will automatically complete the loop with a straight shot from
your current position to your starting point. The enclosed area value
will be displayed in appropriate units. To change units, highlight and
click on the unit abbreviation to bring up a selectable list of choices
(square feet, square yards, square meters, hectares, square miles, etc.)
10. To see the area calculation or if the calculated solution is of value to
you, press . The Saved Track page will open (Figure 18).
However, before you hit save, you should record the data elsewhere. Once
a track log is saved, the total number of track points is condensed (to a
maximum of 500). The Venture HC allows a maximum of 10 saved tracks.
11. Don‟t despair if heavy tree cover causes you to occasionally lose con-
tact with the satellites as you track. The GPS will “connect the dots”
and link your recorded track points in an attempt to estimate the en-
closed area. View the saved track screen to decide whether or not the
integrity of the track was maintained.
12. To view all of your saved tracks, go to: MAIN MENU > TRACKS.