Building a Track
Building a track for analysis in GPS Tracker is done by adding together the trail segments for the track that you wish to analyze. Segments are added to the track by clicking on the red dot that's shown at the center of each segment. As each segment is added to the track the statistics at the bottom of the page are updated to show the distance and elevation data for the currently selected track.
Familiarity with the trail systems depicted on the map is helpful, but not necessary in building a track. It can also be helpful to have a good trail map available for reference, such as the PATC maps for Shenandoah and Massanutten. It's sometimes easier to first identify the trails that make up the track that you're interested in on the trail map and then use that to help find the appropriate segments on the GPS Tracker map.
The following sections describe the steps necessary to build a track in GPS Tracker.
Centering the Map
The first step in building a track is to center the map on the area of interest and display the segments available in that Area.
When GPS Tracker first comes up it will be set to the default area of "Shenadoah National Park - Northern Section". That means it will be centered on the northern section of Shenandoah and only the trail segments in that Area will be displayed. If the trails you wish to document are in a different area you can choose that Area from the drop down list at the top of the page. Simply select an area from the list and click the "Go" button and the map will be recentered on that area and the trail network will be redrawn to show only the trails in that area. After going to that area you might have to center the map on the particular trails that you're interested in by dragging the map.
To move the map a large distance by dragging it's easier to zoom out to a lower zoom level and move the map at that level, then zoom back in on the area that you're interested in. The map can be moved by clicking on the map and drag it.
Zooming In
Once you've centered the map on the area where you want to begin building a track you may need to zoom in to a higher zoom level to select the segments. The current zoom level is displayed at the top of the page. You must be zoomed in to level 13 or greater to select segments from the map. You can also zoom in by double clicking on the map and zoom out by double right-clicking on the map.
Selecting Segments
At zoom level 13 or higher, "selector dots" are displayed in the middle of each segment. A selector dot is a small red dot associated with the segment and it is this dot that you click on to select the segment and add it to the track. If you hover over a selector dot, the program will display a tool tip giving the name of the trail that the segment is a part of. An example of a selector dot is shown in figure 1.
Figure 1 Example of a selector dot
Selector dots may be either enabled or disabled, depending on whether or not the segment is available for selection. GPS Tracker will only let you select a segment that is a continuation of the current track. In other words, it won't let you create a track with "gaps" in it. After a segment is added to the track, the program will enable the selector dots for only those segments that are directly connected to the end of the segment just added. The selector dots for all other segments will be grayed out.
As each segment is selected and added to the current track it will change color to indicate that it's part of the current track. All selected segments will be colored yellow except for the last selected segment which will be colored orange.
Selecting the First Segment
When the GPS Tracker page first comes up and before any segments have been chosen, any segment on the map is available for selection as the first segment in the track. The selector dots on all segments are enabled and any segment may be chosen to start the track.
Normally after the selection of a segment the program will enable the selector dots of only those segments that continue the track in the direction that the user is traveling and disable the selector dots of all other segments. When only one segment has been chosen, it's not possible for the program to determine which direction the user intends to travel on that segment, so the program will enable the selector dots of all segments connected to either end of the first segment.
After the second segment has been chosen the program can determine the user's direction of travel on the track and will enable only those segments that continue the current direction of travel. The program will also display a "You Are Here" arrow indicating the user's current position on the map.
Removing Selected Segments
The program has two buttons for removing selected segments from the current track. The "Back" button removes the last selected segment from the current track and the "Clear" button removes all selected segments from the current track and reinitializes the web page.
The "Back" button can be used to remove the last selected segment from the current track. When the button is pushed it adjusts the segment colors, the availability of the selector dots, the "You Are Here" arrow and the track statistics to reflect the state of the current track just before the last segment was added.
The "Clear" button will clear all of the segments out of the currently selected track and return the program to the state it was in before any segments had been chosen. This allows the user to begin building a new track from scratch. When the "Clear" button is pressed a dialog box will be displayed warning the user that the current track will be lost and asking if it's ok to continue. If the user answers "yes" the current track will be erased. There is currently no way to save a selected track to read back into GPS Tracker later.
Crossing Area Boundries
There may be a case where the track you want to build contains segments in more than one area, such as documenting the Applachian Trail where it crosses from the central section of Shenadoah to the northern section. In a case where a trail segment in the current area connects to a trail segment in a different area, the adjacent trail segments will be drawn in the current area, however when you select one of them it will add that segment to the current track and then transfer the page to the new area, so that the new area becomes the current area and all of it's trail segments are drawn on the map, including any segments that were choosen from the previous area.
Recentering the Track
The "Recenter" button will re-center the map on the currently selected track. This is useful if you've repositioned the map so that the currently selected track is no longer visible, for example, by using the area drop down list to move the map to another area.