Google Earth is an incredibly powerful tool for route planning. This guide describes how to import topographic map layers, navigate 3D terrain, and create routes through the wilderness.
Google Earth has several flavors:
- Phone app.: Potentially useful to impress people at parties, otherwise, not
- Browser app.: Google seems to be slowly transitioning desktop functionality to the browser. Currently  you can view routes in the browser, but can not create them
- Timelapse site: Great eye candy, but not useful for route planning
- Pro: Requires download, but provides full functionality
The following videos demonstrate the functionality described in the text below.
Google Earth Pro comes with multiple Layers options. If your imagery is flat, check the “Terrain” box at the bottom of the list of layers. Roads, Borders and Labels, Places, and Photos are all useful to me. (Google bought and killed Panoramio, which used to feed photos to Google Earth. Many former Panoramio users have moved their photos to mapsights.com.)
Route Planning with Google Earth
Download a Topographic Layer
Google Earth’s satellite imagery is even more useful when paired with a topographic layer.
- The best source for topographic layers is CalTopo. A $20 annual fee grants access to the “superoverlay.kml” which includes USGS 7.5′ topo coverage, as well as shaded relief, slope angle, and other satellite imagery. Be sure to drag the superoverlay layers from Temporary Places to My Places, otherwise they won’t be saved. Trying to work with several overlays will seriously limit render time.
- Earth Point is a free source for a topo overlay. The topo is from Delorme, so familiar to Gazetteer users, and not as detailed as the USGS 7.5′ topo.
- A second free option is to download maps as kmz files directly from USGS topoView. This is a little cumbersome since you have to select the region and zoom level for each map.
View → Historical Imagery
Google Earth displays the highest resolution imagery (usually the most recent) but stores older imagery. By looking at different seasons, the older imagery helps assess snow cover, crevasse fields, and other season variability.
View → Sun
This might just be eye-candy, but if you want to see when the sun finally hits the slope you want to ski, you can use the sun time slider.
- Hover over the tools at the top of the page for ‘Add Path.’
- Resist the urge to draw a path by holding down the mouse button. Drawing a path this way creates a ton of points, which is too cumbersome to edit later, and makes an unnecessarily large file.
- Draw routes by clicking along the intended route. You can come back later to refine the route.
- A common pain point is for people trying to edit routes. The routes are directional, meaning that you might have to move an endpoint and add new points in front of it. In other words, if you draw a route from north to south, you will always have to add points from north to south. Click on the northern point to select it, and draw points to the south of it. Play.
- Right-click on a route → Show Elevation Profile
- Use an online calculator to convert slope percent to angle
Creating/sharing a Route
Routes and points can be saved to kml or kmz files and emailed to trip members for review, edits, etc. We collaboratively identify bail-outs, cruxes, etc.