Wednesday, April 25, 2012

Exporting Map Tiles to Google Earth

Sometimes a flat map just doesn't cut it.  You want to be able to rotate it, skew it, project it onto real-world terrain.  Google Earth is great for this, but their aerial imagery only takes you so far in the backcountry.  You need trails, contour lines, streams - and you need to be able to match what you're seeing with the paper map you'll take into the field.

The view past Half Dome into Tenaya Canyon, Yosemite.
CalTopo now solves this problem by letting you export map layers to Google Earth with only a few clicks.  Simply start the CalTopo map browser, navigate to the area you'd like to capture, and click Export to Google Earth in the left navbar.  Select the map layer you'd like, hit Export, and open the downloaded KML file.


A few things to know:

  • There is a rendering bug with Google Earth that causes transparent images to occasionally show up with black backgrounds.  This unfortunately affects the slope shading and contour layers; a solution is in the works.
  • An export is limited to the current screen, but Google Earth will seamlessly patch multiple exports together.
  • For performance reasons, resolution is limited based on the map bounds.  Zooming in on a map will get you a higher resolution export that covers a smaller area.

Death Valley, CA
Tahoe City, CA circa 1930
If you find a map that looks especially cool when loaded in Google Earth, please post it in the comments section.

4 comments:

  1. This feature is awesome, I used it a few days back. Keep up the great work!!

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  2. I don't see the "Export to Google Earth". Does this require a subscription?

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    Replies
    1. Sorry, the UI has changed significantly at this point.

      For limited extracts, Print -> Print to KMZ.

      For full support while flying around in google earth (basic level subscription required) see http://caltopo.blogspot.com/2016/01/improved-google-earth-integration.html

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