2D Route-Planning: Caltopo, GaiaGPS, Topo maps

Google Earth has no competition for 3D route planning, but the interface can be intimidating to new or infrequent users. These 2D sites are more intuitive for new players of the game.


Gaiagps.com was originally developed as more of a phone app than a browser route-drawing tool, but in the past five years Gaia has added significant functionality to the website. Independent of the phone app (and subscription), the website is my preferred 2D mapping site. Toggle various baselayers, look for public tracks in the area of interest, draw lines, points, etc. And of course, with a subscription, your routes are automatically synced to your phone for off-line use.


Caltopo is the only other 2D contender in my opinion. CalTopo was started by a California SAR member who wanted to provide useful information to his SAR team. Baselayer tiles load quickly, including topo, satellite, shaded relief and more. (Gaia actually serves many of the tiles generated by Caltopo.) Planning and printing can be done for free.

For my purposes, the greatest value from CalTopo is Google Earth integration and the superoverlay.kml, which makes the Caltopo layers visible in Google Earth. You need at least a basic subscription to access the superoverlay ($20/year).

Sign in (upper left) and click on your account name (email address) in the upper left corner. Select the Your Account tab under the View Account window. Click on the KML hyperlink toward the bottom of the window to download the superoverlay.kml.

Useful overlays include slope shading and weather stations. Right-click for elevation profiles and View from Here eye candy. You can import/export routes to/from Google Earth and GaiaGPS.

Topo Maps, Printing

  1. Caltopo offers a very mature printing interface. Unfortunately, I find that most of the maps in Alaska need some contrast adjustment to be workable. Maps can also be exported as Geospatial PDFs, which can be viewed with phone apps like Avenza Maps.
  2. USGS quads can be downloaded and printed for free from topoView.
  3. DNR offers topo maps for view and print, without having to select individual quads.

Other Sites

I don’t think these do anything that Caltopo doesn’t do (better), but here are some other topo map resources:

Hillmap: side-by-side topo/sat, useful overlays such as slope percent
Topozone: Topo map reference


  1. If you have access to imagery–especially Digital Globe’s WorldView 2 and 3 (not to be confused with NASA Worldview above), ArcMap (or some other way to export as geoPDF as you can’t seem to do it in R with RGDAL yet), then using Avenza GPS instead of GAIA is a whole new level of using a smart phone for navigating. MODIS pixels are 250-500 m across (low res); Landsat pixels are 30 m; Sentinel is 10 m resolution (I think ); but DigitalGlobe’s WorldView products (not to be confused with NASA’s Worldview of MODIS) is 1m or less! This is what you see on Google Earth when you see your neighbor’s dog in his backyard.

    The workflow is to export the imagery to geoPDF in ArcMap (most college students can do this), save on an iXpand drive from the computer, then plug into your phone and access with Avenza. This is mind-blowing, by the way, to be able to do this.

    Gaia does not allow this sort of flexibility.

    Also as an aside and cheaper alternative to CalTopo, I just get my USGS topos for free at TopoView, a USGS site, download as kmz, and double.click to open on Google Earth. Again, amazingly simple workflow for super powerful use.

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