By Robert J. Ballantyne

This instruction assumes you have a calibrated map. Every few seconds, while your GPS is receiving and calculating its position, it adds a data point to its Track Log. With the eTrex Summit there are a maximum of 2999 points. Then, as new ones are added, old ones are discarded. Therefore it may be useful to download and date the current file from time to time.

This page describes downloading/uploading Track Log and the Waypoint files and plotting data on a calibrated map.

	When MacGPS Pro loaded it scans the computer for ports. If the USB connector is not inserted, it will not know to use the USB port. So, begin by connecting the GPS to the connector, and insert the USB end into the computer (at least have the USB connector inserted). Now open FILE > PREFERENCES... and in this dialog box, select the USB connector. Failure to insert the USB connector can be very frustrating because the USB option will completely vanish from this dialog box.
	This is a good time to select how you will want the data displayed. Open FILE > MAPPING CHOICES... This dialog box is identical to the one used in calibrating the map, except that there is an additional section at the bottom for UNITS. Note: you may have calibrated the map with NAD27 and the UTM grid because that was the format of the published map. But here you can choose to display the data otherwise. For instance you may choose to display it with WGS84 and one of several Latitude and Longitude grids.
	If the Preferences are chosen, the Mapping Choices are made, and the GPS receiver is ON and connected to the computer, you are ready to download data. Choose TRANSFER > FROM GPS RECEIVER > TRACKLOGS... This dialog box will appear. On the eTrex, go to the MENU page > SETUP > INTERFACE > (I/O format) GARMIN Then click OK on the computer dialog box. If all is well, a thermometer will show the progress of the data transfer. You will be given the opportunity to name the file.
	If you have a calibrated map open, the data will appear on that. If not, it will appear on a blank map. Just close that. The process for downloading Waypoints is exactly the same. Eventually you will have a number of calibrated maps, tracklog files and waypoint files. I keep associated data in folders named for the various maps.
	When you are ready to display the data, begin by opening the appropriate calibrated map. At last this process is about to become very interesting.
	Now OPEN the related data files. In this case there is a track log that shows a ski track from a ridge to the car. I have also opened the associated Waypoint file.
	Plot & Upload New Waypoints There are many ways to look at the data. Here the image is magnified so that the width is only 40 meters, and the grid is 5 meters on a side. It shows the time stamp for each data point in the Track Log, and the software calculated the speed between the points. It is easy to add waypoints to the Map. The sample waypoint is at exactly: Easting 0499840, Northing 5605070 (NAD27, Zone 10U). If you plan to upload these points to your receiver, keep the names short (6 characters max.) and pick an icon that your receiver can use. (When you click to mark a point on the map, a waypoint form appears). To upload the new waypoints that you plotted on the map, first choose FILE > SAVE WAYPOINTS AS... and name the file of waypoints to be saved. Be sure the receiver is connected and choose TRANSFER > TO GPS RECEIVER > WAYPOINTS... and select the waypoint file. The new waypoints will be added to the waypoints in the receiver.
	Plot and Upload A Route (sequence of waypoints) If you have ever tried to use the buttons on a GPS receiver to enter the data for a route, you will appreciate the speed with which you can plot and upload even a complicated route. Because of the difficulty of entering routes, this is a feature of GPS receivers that is sometimes avoided. In the field, you will find that following a detailed route is a luxury. To create a new route, choose EDIT > NEW ROUTE... and pick one of the 50 possible routes. Give it a name. The waypoints for the route may be entered by clicking directly on the map or by entering the coordinates. In this case, I just clicked on obvious points along the ski track. Each click creates a waypoint -- be sure to use icons that are available for your receiver, and keep the waypoint names no longer than your receiver can display. Choose DONE when complete and save the route. That file can be uploaded to the GPS using the Transfer Menu.

Cleaning up the Data

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