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Different types of GPS receivers enable you to store varying numbers of routes, with each route made up of a different number of waypoints (see Figure 8-11).

Once a route has been tracked by the GPS, it can be reversed so that you can backtrack and return to where you began.

FIGURE 8-11: Routes stored in a GPS

Working with the Data

As you can see, a considerable amount of data is stored in a GPS, which means that you need to be able to access it and work with it. Two principal tasks come into play here:

Working with the data you have already collected with the GPS

Creating new data for upload

Before you can work with existing data, you have to get it off the GPS. Most tools that enable you to download data from a GPS also enable you to edit the data and work with it at a fundamental level, editing every aspect of the data. Some purists think that editing any data gathered by your GPS is not appropriate and prefer to keep it unedited, but others believe that because it is their data, they can do what they wish with it. There is merit in that opinion — perhaps you made a mistake when creating a waypoint, took a wrong turn in your journey when you were recording a route, or missed a few points along the way that you want to add after the fact. Another good reason to download data from your GPS is that it frees up memory on the device, enabling you to collect more data.

Everything about the data is editable. Just because you created a route or waypoint while on the move doesn’t mean that you can’t edit that data later.

At this point, you might be wondering why you have to download the data. Can’t you just edit the data while it is still on the GPS? You can, but the problem is that you have to input numbers and data using an input system that is generally prone to error. Furthermore, remember that when you enter and edit data on a PC, you will normally have the capability to undo any changes you make, a handy feature not present in the GPS interface.

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The great thing about tools that can retrieve data off your GPS is that they also enable you to create new data for upload to the GPS. This is invaluable for planning trips. For example, it is much easier to create a route as of a set of waypoints on the PC than using the interface provided by most GPS receivers. In addition, your PC provides you with access to more information (digital maps perhaps, or Internet resources) to make planning easier. You can generally accomplish more in an hour of waypoint and route management on a PC than you can with several hours using the GPS. The more data you have to work with, the more vital the PC or handheld device becomes. Errors are dramatically reduced too, which means that your trip will be a safer one. Remember that when you are creating data, you need access to reasonably accurate information on the coordinates of items, for which you will need access to maps — either paper maps or, better still, digital mapping applications.

One of the easiest ways to get this information is to use free applications. Many are available, but we will examine two of the best:

EasyGPS

G7toWin

EasyGPS

EasyGPS (shown in Figure 8-12) is a free software tool that enables you to work with data stored in Garmin, Magellan, and Lowrance GPS units. EasyGPS is one of the easiest ways to work with the data on your GPS receiver. You can download the latest copy of EasyGPS from www.easygps.com.

FIGURE 8-12: EasyGPS

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After you have downloaded and installed the application, you are ready to work with the data:

1.Set up EasyGPS so that it can detect your GPS receiver. Click File Preferences to bring up the Setup dialog box (see Figure 8-13).

FIGURE 8-13: Setup screen on EasyGPS

2. Click Add GPS. This brings up the dialog box shown in Figure 8-14.

FIGURE 8-14: Selecting the appropriate GPS receiver

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3.Select the GPS that you have and click OK.

4.The GPS Settings dialog box appears. Select the serial port to which the GPS unit is connected (see Figure 8-15). Click OK twice.

FIGURE 8-15: Selecting the serial port

5.To test your settings, click GPS Test Serial Connection. The dialog box shown in Figure 8-16 appears. Click OK to begin the test.

FIGURE 8-16: Testing the connection. This attempts to communicate with the GPS using the connection settings specified.

6.EasyGPS will detect the serial port. If the GPS is switched on and has satellite lock, it will detect the GPS type and version numbers (see Figure 8-17).

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FIGURE 8-17: EasyGPS detecting the GPS

Now you can use the application to send and receive files from the GPS.

1.Click File Open. Navigate to the folder in which EasyGPS is installed and open the sample files included.

2.This loads the data into the application, as shown in Figure 8-18.

FIGURE 8-18: EasyGPS sample file data displayed

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3.Now you can upload the data to the GPS. Click the Send button. EasyGPS will ask you to confirm what you want to send to the GPS (waypoints and routes) and the GPS to which it is being sent (see Figure 8-19).

FIGURE 8-19: Sending data to the GPS

4.Click OK for the process to begin. A progress dialog box will appear, as shown in Figure 8-20.

FIGURE 8-20: Data transfer in process

5.Now you can check the GPS to determine whether the waypoints (see Figure 8-21) and routes (see Figure 8-22) have been sent to the unit.

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FIGURE 8-21: Waypoints transferred to the GPS

FIGURE 8-22: Routes transferred to the GPS

6.Now click the New button (see Figure 8-23). This will bring up a blank window, although you can still change to the previous window by clicking the tab at the bottom of the screen (see Figure 8-24).

FIGURE 8-23: Opening a new, blank window in EasyGPS

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FIGURE 8-24: Navigating between data windows

7.Click the Receive button to download the data on the GPS into the application.

8.You will be asked what you want to download (see Figure 8-25).

FIGURE 8-25: Selecting the data to download

9. Click OK to begin the download process (see Figure 8-26).

FIGURE 8-26: Starting the download process

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After you have the data downloaded from the GPS, you can set to work editing the data. A waypoint is a convenient way of packaging all the data relating to a positional fix. This data includes the following:

Coordinates

Date and time of waypoint marking

An icon to represent the waypoint

Height data

Different manufacturers store different information in a waypoint. For example, Garmin units enable you to specify an icon to represent your waypoint from a gallery of icons (that range from urban markers such as libraries and gas stations to rural ones for places such as fishing spots, cabins, and camps). These icons are often common to a manufacturer, a range of units, or maybe even a few brands.

As mentioned earlier, there are many reasons why you would want to edit a waypoint — perhaps you marked the wrong spot, gave it the wrong name, or just want to add more information to it after the fact. Whatever the reason, and no matter what you want to change, it can be changed later quickly and easily on the PC.

The following list describes the items you can change:

Description of waypoint: This is a short description of what the waypoint actually is. Only some GPS receivers store and display this data field. If your receiver does, then it’s a good idea to use it because waypoints can be hard to keep track of and knowing which is which in the field based on a short title is tricky. The downside of this data field is that the more text you put here, the more memory the device consumes (which is why some units don’t store this data at all).

Waypoint: This is the name you give to the waypoint. Ten characters is the maximum allowed by EasyGPS, but I suggest that you try to keep the name under eight characters long, as some units will truncate it down to this.

Comment: This field enables you to enter comments to augment the description. Some GPS receivers and software use this to store date and time information about the waypoint, while others ignore it.

Type and Symbol: These two items are interrelated. The icon is a visual marker used by the GPS to represent the type of waypoint, either displayed on a map or as a list. Choose the icon that most closely matches the type of waypoint you are describing, as this makes finding the right waypoint a lot easier.

Latitude, Longitude, and Elevation: This is the core information that forms the basis of the waypoint.

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1.To edit a waypoint, right-click on the waypoint and choose Edit Waypoint (see Figure 8-27).

FIGURE 8-27: Bringing up the Edit Waypoint dialog box

2. This brings up an Edit Waypoint dialog box (see Figure 8-28).

FIGURE 8-28: Edit Waypoint dialog box

3.This dialog box is the powerhouse for editing waypoints. Here you can change everything that there is to change about the waypoint (see Figure 8-29).

4.You can also create new waypoints by right-clicking in the waypoint area of the screen and choosing New Waypoint. This brings up the dialog box shown in Figure 8-30. After

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you create a new waypoint, you can enter any information relating to this waypoint. Of course, the most important information are the coordinates (latitude and longitude), which you can read off of a map. Chances are good, however, that you won’t be able to get a set of coordinates that are as accurate as those that you could get from being at the actual location, but it should be enough to get you there, especially if you choose an obvious landmark (visit www.maptools.com for transparent overlays for paper maps that make getting an accurate coordinate possible). With digital maps, the coordinates of the location at the cursor are normally given to a high degree of accuracy. If you choose a good landmark that’s easily visible, then the actual coordinates can be off by several hundred feet and not make a difference because once you are in the vicinity you can navigate by sight.

FIGURE 8-29: Changing waypoint information is easy, but take care in case you accidentally change information such as the coordinates of the waypoint!

FIGURE 8-30: Creating a new waypoint

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When you have finished editing the waypoints, you can either send the updated data to the GPS or save the file. You can save the information in two different file formats (see Figure 8-31):

TopoGrafix Data file (.loc)

GPS Exchange file (.gpx)

FIGURE 8-31: You can save the stored information in EasyGPS in two different file formats, which can be later opened either in EasyGPS or another compatible tool.

These two files are fundamentally different. The .loc files are binary files (see Figure 8-32), and while they can be opened in a text or hex editor, they cannot realistically be edited without using either EasyGPS or another application that can edit .loc files. For more information on the TopoGrafixs file format and editing applications, visit www.topografix.com.

The .gpx output file is a different matter. This file isn’t a binary file but a text file that is laid out in a format known as XML (eXtensible Markup Language). If you have experience with creating web pages or XML in general, this will already be familiar to you. The great thing about these files is that they can be edited directly with nothing more than a text editor, which is a real bonus if you are in the field when you want to edit them.

Here is part of the contents of a typical .gpx file:

<?xml version=”1.0” encoding=”ISO-8859-1” standalone=”yes”?> <gpx

version=”1.1”

creator=”EasyGPS 1.3.7 - http://www.topografix.com” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns=”http://www.topografix.com/GPX/1/1” xsi:schemaLocation=”http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd”>

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<metadata> <time>2004-11-18T15:59:12Z</time>

<bounds minlat=”42.430910” minlon=”-71.107900” maxlat=”42.435720” maxlon=”-71.104360”/>

</metadata>

<wpt lat=”42.431709938” lon=”-71.107839939”> <ele>39.058960</ele><time>2004-11-18T15:48:31Z</time> <name>BENCH</name>

<desc>BENCH</desc> <sym>Scenic Area</sym> <type>Scenic Area</type> </wpt>

<wpt lat=”42.435669968” lon=”-71.104429930”> <ele>76.550171</ele><time>2004-11-18T15:48:31Z</time> <name>CACHE</name>

<desc>CACHE</desc>

<sym>Waypoint</sym>

<type>Waypoint</type>

</wpt>

<extensions>

</extensions>

</gpx>

This file contains a lot of editable information, and provides you with easy access to the heart of the data. Let’s walk through some of the data the file contains:

<?xml version=”1.0” encoding=”ISO-8859-1” standalone=”yes”?> <gpx

version=”1.1”

creator=”EasyGPS 1.3.7 - http://www.topografix.com” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns=”http://www.topografix.com/GPX/1/1” xsi:schemaLocation=”http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd”>

FIGURE 8-32: Binary format of the .loc files

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The data at the top of the file is called the header data and contains information about the what the file is, what created it, and where the layout of the file is stored (the TopoGrafix website). Leave this information alone, as making changes to it can cause the file to be unreadable by EasyGPS:

<metadata> <time>2004-11-18T15:59:12Z</time>

<bounds minlat=”42.430910” minlon=”-71.107900” maxlat=”42.435720” maxlon=”-71.104360”/>

</metadata>

The next section of the file contains information relating to the range of data held by the file. The terms minlon and minlat stand for minimum longitude and minimum latitude, respectively, while maxlon and maxlat stand for maximum longitude and maximum latitude, respectively. This is used by the file to speed up the sorting of the data by latitude and longitude:

<wpt lat=”42.431709938” lon=”-71.107839939”> <ele>39.058960</ele><time>2004-11-18T15:48:31Z</time> <name>BENCH</name>

<desc>BENCH</desc> <sym>Scenic Area</sym> <type>Scenic Area</type> </wpt>

Next you come to the data relating to the waypoints themselves. The data is quite straightforward to read and edit. Latitude and longitude (lat and lon) are stored in degrees and decimal degrees, with – used to signify southern latitudes and eastern longitudes. The + symbol is not required for northern latitudes and western longitudes. All the coordinates used are relative to WGS84. Time is stored in Universal Coordinated Time (UTC) format and not local time. Name and description are text fields and symbol specifies the type of symbol used; type enables you to enter a text description for the symbol. Symbols are device-dependant and I recommend that you only edit these with the appropriate software. Elevation (ele) information is in meters.

You can edit these values with any text editor to whatever value that you want. For example, let’s say that when you look at the map, you find that the elevation at the site for the coordinates is 55 meters instead of the 39.058960 (a measurement that is accurate to a fraction of a millimeter and totally unrealistic for a GPS), you simply change the value. While you are at it, change the time too:

<wpt lat=”42.431709938” lon=”-71.107839939”> <ele>55.000000</ele><time>2004-11-22T12:31:00Z</time> <name>BENCH</name>

<desc>BENCH</desc> <sym>Scenic Area</sym> <type>Scenic Area</type> </wpt>

Using the format laid out, you can also use the file to create new waypoints. The basic skeleton that holds the data is as follows:

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<wpt lat=”xx.xxxxxxxxx” lon=”xx.xxxxxxxxx”> <ele>xx.xxxxxx</ele><time>YYYY-MM-DDTHH:MM:SSZ</time> <name> </name>

<desc> </desc> <sym> </sym> <type> </type> </wpt>

You can add the data to this framework. You have to do it by hand, so care is needed to avoid errors. In the following example, I have added latitude and longitude information, elevation data, date and time information, along with name, a description, a symbol, and a type.

Notice that the latitude and longitude information is entered between the quotes (lat=” “ and lon=” “), while the rest of the data is placed between the appropriate element’s opening and closing tag (an example of an opening tag is <ele>, while the corresponding closing tag is </ele>):

<wpt lat=”42.432232311” lon=”-71.108355658”> <ele>50.000000</ele><time>2004-11-22T12:32:00Z</time> <name>PLAQUE</name>

<desc>Marker</desc> <sym>Scenic Area</sym> <type>Scenic Area</type> </wpt>

Shown below is a full template that you can use to put waypoint information into the TopoGrafix file format:

<?xml version=”1.0” encoding=”ISO-8859-1” standalone=”yes”?> <gpx

version=”1.1”

creator=”EasyGPS 1.3.7 - http://www.topografix.com” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns=”http://www.topografix.com/GPX/1/1” xsi:schemaLocation=”http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd”>

<metadata> <time>YYYY-MM-DDTHH:MM:SSZ</time>

<bounds minlat=”xx.xxxxxx” minlon=”xx.xxxxxx” maxlat=”xx.xxxxxx” maxlon=”xx.xxxxxx”/>

</metadata>

<wpt lat=”xx.xxxxxxxxx” lon=”xx.xxxxxxxxx”> <ele>xx.xxxxxx</ele><time>YYYY-MM-DDTHH:MM:SSZ</time> <name></name>

<desc></desc>

<sym></sym>

<type></type>

</wpt>

<extensions>

</extensions>

</gpx>