Module 4: Using GPS
- Understand GPS and the types of GPS
- Turn on GPS
- Understand factors that affect GPS accuracy
- Understand tracks and waypoints
- Collect data using GPS
- GPS settings
- Copy GPS data (tracks and waypoints) to computer
- Open waypoints and tracks in JOSM
- Upload GPS tracks using JOSM
- Edit OSM based on GPS data in JOSM
In this module we see what a GPS does and how it works. We explore
how to operate a GPS and how to use it to create maps. We will
explain how to operate the Garmin eTrex Vista HCx, a common GPS used for
mapping. There are many other models of GPS which do the same thing, so if you
are working with a different one, don’t worry - the principles remain the same.
1. What is GPS?
A GPS is like a mobile phone, except that instead of receiving radio signals
from telephone companies, it receives signals from satellites that are going
around the Earth. By receiving these signals from the satellites,
a GPS is able to calculate its exact location on the planet. It records
this location in coordinates, which are two long numbers. One number tells
you how far east or west you are - this is called longitude. The second
number tells you how far north or south you are - this is called latitude.
Every place on Earth has unique geographic coordinates.
For example: -8.639298 Latitude, 116.311607 Longitude is a location in
Google Earth software, showing coordinates of a place in Lombok, Indonesia.
Garmin eTrex Vista HCx
2. Turning on the GPS
- Before turning on your GPS, go outside where you have a clear view of the
sky. Because the GPS determines your location by receiving signals from
satellites, it won’t work indoors.
- On the right side of the GPS, press and hold the Power button.
The GPS will start, and it will show you the Satellites page. You
should see something like the image below. The GPS is looking for satellite signals.
When it has connected to three or more satellites, it will have your location.
- Once your location is determined, the Satellites page will
disappear and you will see the Main Menu.
4. Tracks and waypoints
A GPS records two kinds of information that are useful for creating maps
or saving the coordinates of a place. First, it allows you to save your
location in the memory of the GPS. When you save a location,
the coordinates will be saved with a name. For example,
your first saved point will be named 001, the second 002,
and so on. When you save a point, you can write down the number on a piece
of paper, along with a note about what it is, and any attributes or
indicators you would like to collect. Saved locations on your GPS are called
Second, a GPS can save what are called tracks. While a waypoint only
saves a single location, a track will save a series of locations wherever
you move. For example, a track will record your location every one
second, or every one metre, and the result will be a series of dots that
show the path of where you have been. Tracks are useful for mapping objects
that are represented by lines or shapes, such as the course of a road
or the shape of a field.
A GPS can record a single point as well as a path of where you
travel. Here the points are numbered in the order they are recorded.
The path or track is shown with a green line and the
waypoints are shown in red.
5. Saving Your location
- To save your current location as a waypoint, click the X button until
your reach the Main Menu. Using the joystick, move it so that Mark
is highlighted on the screen. Push the joystick button down to open the
Save Waypoint page.
You can see on this page some information about the waypoint that you are
saving. First is the name. If this is your first waypoint,
it probably reads “001”. This is the number you should record on paper
along with the information you want to collect with this object. Next you
will see the time and date when the point is recorded. Below that are the
coordinates, followed by the altitude.
- Use the joystick to move to the OK button at the bottom of the
screen. Press the joystick button down to save this point. Be sure to write
down the number of the point, along with what the place is and any other
information you want to record about the place in your notebook.
- Press the X button to go to the Map page. You should now see your point
on the map.
6. Turning on the Track Log
Now that we have learned how to save points, let’s learn how to turn the
track log on and off. When the track log is turned on,
it will automatically record your path. It’s good practice to turn on the
log when you begin mapping, and turn it off when you are finished. You
will then be able to look at the track on a computer and see the path that
you mapped. If you would like to map the course of a road,
it is a good idea to save a waypoint at the beginning and end of the road,
writing in your notebook the name and type of the road,
and any other important information about the road.
- Click the X button until your reach the page
that says Track Log.
- To empty the track log (to delete earlier recordings),
use the joystick to select Clear, and press the joystick down.
The bar at the top should read “0%”.
- To turn on the log, move the joystick to highlight On,
and press the joystick down. The track log is now recording your path.
Under Setup, you also can set time or distance
intervals to track. Time intervals instruct your GPS to record your location
at given intervals. If you have a memory card in your GPS, it is good
practice to set this to one second, meaning that every second your location
will be added to the track log. This may be useful when detailed surveys are
See GPS Settings for more information on setting
up the track log.
- Press the X button to go to the Map page. As you move you will see
your track shown as a series of dots.
7. GPS settings
Here we demonstrate how to edit some of the core settings of the GPS
device. Use this as a reference to set up your GPS properly.
7.2. Unit settings
- From the Main Menu, go to . Here the
type of measurement units can be set, such as metres, feet and more.
The location unit format is also set here (decimal degrees, decimal
minutes degrees, second minutes degrees), datum (standard WGS 84) and
projection (standard WGS 84).
7.3. Time settings
- From the Main Menu, go to . Here the time
format is set (12 hours or 24 hours) as well as the time zone. It is good
to have the local time set, because all tracks and waypoints
saved in the device are also saved with the current time.
7.4. Page settings
Remember that when you press the Page button (the X)
you are able to switch between different menus. By editing the page
settings, the pages, as well as their order, may be customised.
- From the Main Menu, go to .
- Add a new page to the list by selecting Add Page. Then select
a page such as: Tracks (to see details of your trip),
Map (to view maps), or Satellite (to view the
satellite status, position, and accuracy).
- Click on one of the pages to move it around the list and change
the order in which the pages flip.
7.5. Track settings
Remember that tracks are a bread-crumb trail
recording your movement, which is useful for mapping roads. On the Track
page there are several settings.
- From the Track page, click Setup.
The settings are as follows:
- Wrap When Full: This option should be checked. It means that when the GPS
runs out of internal memory, it will start overwriting the oldest trackpoints
to record new ones. It is a good idea to keep this checked, although typically
you will be recording tracks to a memory card anyway, making this option
- Record Method: There are several ways the GPS can record track points:
- Distance: tracks a new point each time a certain distance has been covered
- Time: tracks a new point when an amount of time has elapsed
- Auto: automatically choose method (typically this should be selected)
- Interval: This setting indicates how often the GPS will record the track,
depending on the method selected in Record Method. Using a high setting
(collecting many points) here will result in tracks that are smooth and
detailed but will also drain the battery faster. If Record Method is set
to Auto, the Interval options will be as follows:
- Most often
- More often
- Less often
- Least often
If Record Method is set to Distance or Time, the options will allow
you to set a matching unit of measurement.
- Color: This setting is for defining the colour of the track line as
shown on the GPS map page.
8. Copying waypoints and tracks to the computer
8.1. Attaching GPS to the computer
When you are finished mapping with the GPS you will want to copy the
points and tracks to your computer so that you can open them in JOSM.
- First, turn off the track log on your GPS by going to the Track page and
- Attach the GPS to your computer with the cable. One end should plug into
your computer’s USB port, and the other goes into the back of the GPS,
beneath the rubber flap at the top. The GPS should be turned on to copy
the points and tracks.
8.2. Installing GPS drivers
- You may need to install GPS drivers on your computer. Open your training
folder and find software/USBDrivers_23.exe. Double-click it and
- If you don’t have this file, you can download it. Open your internet
browser and go to: http://www8.garmin.com/support/download_details
- Click Download to get the installation file. Locate it on your
computer, and double-click to install.
8.3. Getting the GPSBabel setup program
- GPSBabel is a program that allows us to copy data from the GPS. It is
saved as GPSBabel-1.5.1-Setup in the software folder (the
exact version number may be different).
- If you don’t have GPSbabel already, open your web browser and go to
- Click Downloads at the top of the page.
- Scroll down the page. If your computer uses Windows,
you want to download the installation file for Windows. Click
GPSBabel-1.5.1-Setup.exe. The file will be downloaded to
8.4. Installing GPSBabel
- Locate the GPSBabel setup file on your computer. Double-click it to install.
- Click Next.
- Click I accept and Next.
- Continue clicking Next until the program installs.
- When the program has finished installing, click Finish to start
8.5. Copying Tracks and Waypoints
- Click in the circle next to the word Device at the top of the
- In the drop-down menu labelled Format, select
Garmin serial/USB protocol
- Go down to the middle of the window, under Output. In the
drop-down menu labelled Format, select GPX XML:
- Click File Name and type a name for your saved file. It should be
something that describes the data, such as the date and the location. For
- Make sure your GPS is connected to the computer and turned on.
- Click Apply in the bottom right corner of the window.
- If all goes well you should see a bar move across the screen,
indicating that the data is being retrieved from the GPS. When it is
finished, your points and track will be saved in the file that you selected.
8.6. Opening in JOSM
- Now open JOSM. Go to
- Find and select the file that you created with GPSBabel. Click
You should now see your points and tracks loaded into JOSM.
9. Uploading GPS data in JOSM
If you are not interested in sharing your tracks publicly on OSM,
feel free to skip this section.
Adding GPS tracks to the OSM server is useful because it enables other users
to see and use your tracks. For those who do not have a GPS or who can’t
access a location, they are still able to benefit from your work and
help improve the map.
The easiest way to upload GPS tracks is to download the JOSM plugin
- Open JOSM and go to . Click the plugins
- Type directupload in the Search box. Check the box next
to the plugin, and then click OK.
- Restart JOSM.
- Open your GPX file in JOSM.
- Go to
- Add tags, a description, and choose an option for whom to make the track
visible. Unless you have a reason for doing otherwise, choose
- Click Upload Trace. If requested to enter a username and password,
enter the credentials of your OSM account and click
Go to next module –>