Here are some notes on our route planning for long traverses/Wilderness Classics. I haven’t relied on maps or compasses in years, and though I acknowledge is takes away part of the sense of adventure, I’ve been grateful to have a route on my GPS when it looks like this:
I don’t just tag waypoints and connect the dots- I draw the entire route, including bail-outs, secondary options, potential airstrips, etc.
My workflow is two-step: route selection with Google Earth, then transfer to the GPS unit.
I create a folder within Places (“My Places”) to house the points and line segments for the trip. Google Earth often loses these folders when the program crashes, so I save the folder (right click –> Save Place As –> filename.kmz) at the end of each session.
Satellite Imagery: Resolution varies from being unusable to good enough that you can decipher game trails.
Time-Stamps: The satellite imagery is time-stamped (bottom left corner of the screen) which is particularly useful for gauging crevasse cover. Click on the time stamp to activate a time scroll bar; depending on the historical imagery you can compare snow cover for different months/years.
Photos: I turn on the ‘Photos’ layer and use the photos to gauge vegetation, crevasses, etc. The photos usually get me excited about the trip.
Topo maps: Google Earth’s satellite imagery is much more useful coupled with topo maps. The Geographic Information Network of Alaska (GINA-UAF) provides a free USGS Topographic Map baselayer for Alaksa (download the kml file). I toggle between the baselayers to pick out route options. I’ve heard that similar base maps exist for other areas, so try an internet search for your area.
I use the placemark tool (yellow thumbtack) to tag locations of airstrips, cabins, and other points of interest. I use the path tool (three dots with line) to sketch lines wherever I see good travel options. Initially I have a mess of line segments, and as the route starts to define itself I look for ways to connect line segments for a through-path. I don’t delete the other path options- they could be useful if plans change. I use the ‘Description’ tab to enter segment length (which you can easily pull from the ‘Measurements’ tab) and any other notes. This information does not get transferred to the GPS.
I label all path segments with short labels; my Garmin GPS only takes the first 10 characters of the labels.
Transfer to GPS
Google Earth does not have the capacity to transfer features to GPS units. Fortunately, there are plenty of geospatial coders that have built workarounds. I’ve been using GPS Babel, free software very worthy of donation.
1.) I copy and paste my Google Earth folder to create a duplicate of all the line segments, then clean out the lines/points I don’t want transfered to the GPS.
2.) Export the ‘clean’ Google Earth Folder as a .kml file (not .kmz).
3.) Open GPS Babel
Input: File –> Format –> kml –> “file name”
Select which features to input (Waypoints, Routes, Tracks)
Output: Device –> Format –> Name
The upload takes about 2 seconds.
For the Garmin etrex Vista, you have to turn on the line segments manually by selecting: Main Menu –> Tracks –> select a track –> then activate the ‘Show On Map’ option.
Feel free to contact me if any of that doesn’t make sense.