Thursday, June 26, 2008

Digital Prospecting With Google Earth

For those who do paleontological prospecting in new field areas, I probably don't have to spend too much time singing the virtues of good satellite imagery. Perhaps the single best thing about it is that it can allow you to quickly evaluate where the worthwhile exposures are, and where the low-relief, grassy pastures are covering up perfectly good fossiliferous rocks. Used in concert with a geological map, this "digital prospecting" can save a lot of time and annoyance out in the field.

There are two ways to go about this. . .one is by old fashioned aerial photographs and a geology map. The other is by using Geographical Information System (GIS) software. Because I've barely touched GIS since I took a course as an undergraduate (and I am lucky enough to have a skilled friend who volunteers for the occasional map-making project; one of these days I'll get around to learning GRASS), in this post I'll focus on the "lazy researcher's GIS" -- Google Earth.

Now in version 4.3, this digital globe runs smartly in Windows, Linux, and presumably the Mac OS (although I've never tried the latter). Find a prospective field area, and do a virtual fly-over to locate promising outcrop. Mark prospective points, and transfer the coordinates to your GPS unit. It's that simple!

So what are the upsides of using Google Earth?
- It's free!
- Pretty much global coverage.
- The user interface is intuitive, without a lot of annoying extras.
- High resolution (in many areas)

And the downsides?
- An internet connection is pretty much required, if you want to go someplace that isn't already in the cache. So, don't plan on being able to use it that well in the field.
- The DEMs (digital elevation models) are pretty crude in most areas, and don't necessarily show detailed topography all that well, if you want to pan around an actual landscape.
- It's tough to import GIS data, if you want to add geological data or something (although it can be done - to be addressed in the next post). Furthermore, basic GIS functions, such as intersections of layers, just can't be done easily within the program itself (as far as I know).
- Resolution varies across the maps. Sometimes the remotest areas have crisp, true-color resolution - and the field area just around the corner is a fuzzy, false color mess.
- Township and range aren't supported by default (but see an upcoming post for a solution!).

Is Google Earth useful for paleontologists?
If you're in the early stages of a field project, or are trying to evaluate outcrop potential in a far-away locale, Google Earth is perfect. But, be aware that this program is not a complete substitute for a good GIS package (and a person to run it!) for many tasks, and satellite coverage limitations may cause problems in some regions. For the most part, though, Google Earth is a quick, cheap tool for planning out a field season (and one that I use quite frequently!).

Coming up. . .Handy tips and tricks to make the paleontologist's use of Google Earth easier.


Anonymous said...

... just wanted to mention that NASA's Worldwind offers much better imagery offshore, e.g. Bahamas, Maldives, etc. The quality of maps and images is especially good above the U.S.: aerial images, topographic maps, etc. And despite Google_Earth it is open source. It's freely available from

Andy said...

Thanks for the tip! I played with this program a little bit. . .my general take on Worldwind at present is "wait and see." The resolution over most of the places I looked in the US (except for metropolitan areas) was inferior to Google Earth (especially for potential field areas). . .better offshore imagery is certainly a plus, though (but none of the areas I looked at in Madagascar were nearly "satellite prospecting" quality). The other major annoyance is that the primary release is Windows-only (although there is a Java version now), and the features are limited. I'll cross my fingers for continued improvement, and addition of some higher-resolution images in the near future. :-)