Undergraduate geology map overlay in Google Earth
I have been updating my guide to our students on how to complete their independent mapping dissertation and thinking about the use of Google Earth after a number of posts, including mine, looked at the use of One Geology maps and Google Earth. The One Geology maps are a bit too large scale for use in undergraduate mapping areas, which for UK students at least are only a few kilometres wide, but it was the post by the Lab Lemming who uploaded some of his own fantasy Dungeons and Dragons maps that alerted me to the fact than any scanned image could be uploaded and georectified.
I’m sure that I’m not the first one to try to upload undergraduate geology mapping into Google Earth but a quick search of t’interweb doesn’t turn up much so I thought I’d give it a try and blog the results. Our students map in the Cantabrian Mountains of Northern Spain which has some nice relief to it to drape the mapping over. Bizarrely, through historical accident, although I’ve never been to the area, I have responsibility for the dissertation guide. We have just had to move areas by a couple of valleys due to an incident between students from another university and some migrant workers so I can safely use a map from a couple of years ago and not give the game away to the current students as to the exact nature of the geology.
Georectifying geology map
Inserting the scanned overlay from the Add menu was very easy. Georectifying the image was a but fiddly at first by dragging the overlay edges to their correct location but this was largely due to my not having been there and knowing the area. If I have to do it again it will be a lot quicker. Setting the overlay transparency to about 50% and turning the roads layer on in Google Earth and then matching roads and river valleys proved the best way to do it in the end.
The results I think are quite stunning and could be very useful in future mapping projects. Using it in the field (or at least at the hotel in the evenings) could be used to check the mapping accuracy and even scout for new localities.
Second view of geology map overlay
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That’s a fantastic idea! I immediately had to try that myself and share it with my blog, too. It is amazing how easy it is actually and that so few people seemed to have had the idea before!
Hy there,
First of all I think this is a verry neat thing, that you can overlay geological maps in google earth.
My question is how can you make the geo map to be “attached’ to the ground, like the geo map beeing deformed after the mountains and vallets, following the topography?
I have tried to attach one map and mine is “flat” it is not following the topography.
It was actually like that by default for me. If you right-click on the map name in the Places box and select Properties go to the Altitude tab. Altitude should be 0m and “Clamped to ground” rather than “Absolute”.
That´s wonderfull! Easy to install and moving in all 3D-directions. I tried it with geoagnetic RTP-results and it works too. In my opinion, Google Earth is after GPS-revolution for civil use in the nineties, the second revolution to massify “Geoscience” worldwide. Free for everyone ..using to produce new output.. that´s the point.
Did you have to change the size of the overlay somehow? When I add them they are not the right size, yet, and I need to change it by dragging the edges outward or inward to make it smaller or bigger but it is distorting it a bit.
Yes, you have to resize them, either by dragging the green marks at the side or the corners. Dragging the diamond will rotate the overlay. It is a bit fiddly at first but with a bit of patience it should work.
The fit might depend on the map projection you are scanning from. Google Earth assumes a simple cylindrical projection (Lat/Lon WGS84). If you are using UTM it will only work well over a small area.
Full overlay user guide.
Thanks for the hints! I thought there might be a more “advanced” method to add an overlay.
I think the ‘advanced’ method is if you know the lat/longs of the corners then you can enter them in the location tab in the properties dialogue box
I might try that.