Google Earth Lessons

An Educational Resource for Teachers

Insta-Topos with WMS

Here’s a slick little trick!

 

Add dynamic topographic maps to pretty much anywhere in the U.S. in under two minutes!

This trick takes advantage of Google Earth’s ability to query Web Mapping Services (WMS) around the world. You can do a lot more than topo maps, but it takes some experimenting since some of the services are specialized to specific regions, different data (map) types, or are just not available at all times. (there are some caveats, see the tips at the bottom of the page)

In a nutshell, here are the steps…

1. Zoom in to somewhere in the US.

2. Add a new Image Overlay.

Add a new overlay

3. You can name it something appropriate, like ‘View Topography’, then click on the ‘Refresh’ tab.

New Overlay Window

4. In that window you want to select ‘After Camera Stops’ then click on the ‘WMS Parameters’ button. Tip: There are a lot of other settings you can explore here, such as setting the delay or if you only want the layer to show up in a specific locale. Feel free to click on things to try them out. You can always create a new Image Overlay if things get too messed up!

5. In the window that appears, scroll down the list of WMS servers until you hit the one that says ‘terraservice’ (they are alphabetical, so it is most of the way down).

Select TerraService

6. After a second or two a whole huge list of map choices appears. Scroll about halfway down, select the style you want (black lines are good, but they all work well) by clicking on it, then click the ‘Add’ button. Click the ‘Apply’ button and keep an eye on Earth behind the window to see if it worked. If it did, click OK. Then click OK to close the Edit Image Overlay window.

Apply Layer

7. That’s it! Now you have topographic data shortly after your view stops.

Finished!

The WMS capabilities of Google Earth can be very powerful, allowing you to instantly view a diverse range of information around the globe.

Different servers have different information and it can be a challenge to find the data you want, but when you find it you can access it whenever you need to simply by activating the placemark.

Some WMS tips:

  • The U.S. and Canada have the widest range of data.
  • You can scroll through the servers one by one to see what data is available by using the arrow key on the keyboard.
  • A little over half the servers don’t seem to want to ‘talk’ to Google Earth.
  • My favorite servers include the TerraService, JPL and gisdata.usgs.net. With them you can display anything from vegetative growth levels, sea temperatures, rainfall averages, all sorts of great information. Most of the .ca, Canadian government, ones are really good too.
  • You can add your own WMS servers should you find one not on the list, but don’t ask me how since I couldn’t get any of the public ones I found at http://www.skylab-mobilesystems.com/en/wms_serverlist.html to work. If you know how, drop me a line so I can share the info with others (david AT gelessons.com)
  • The greatest drawback is that there is not a legend included in the served overlay to identify what colors or symbols might mean. This might make a good research project for students, or a good lesson on how we derive meaning from possibly arbitrary colors and symbols.
  • The WMS overlays don't behave well with the view tilted much. You have to be looking pretty much straight down at the ground if you use the dynamic ('when camera stops' or 'on request')
  • Is it just me, or does some of the Google Earth elevation data not match exactly with the topo data?

Enjoy!

David