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I’ve said it before, and I am sure I will say it again. But this time Google Earth is really making a major difference in my approach to making a geologic map.

My mapping project on the Lower Walker River and the piedmont of the Wassuk Range, NV is taxing my skills as a geologist and as a mapper. It is an extremely complicated setting with active tectonics, catastrophic debris flows, rock avalanches, a wildly fluctuating terminal lake, and a river madly scrambling to keep up with the lake’s rapid, historical decline (50 m in ~100 years). Documenting the ancient, historical, and recent shorelines along the lake is a key component of developing a fairly tight chronology of alluvial fans, abandoned delta lobes, and Quaternary fault activity. However, efficiently digesting all of this information is a far more laborious task with the 24k USGS base maps because the relief in the area is too extreme to accommodate small contour intervals. Air photos are certainly nice, and I do have access to some marginally good LiDAR data and scattered high-precision GPS points, but nothing brings the area into full focus as easily and as efficiently as Google Earth. On this project I have explicitly incorporated GE into my mapping and it has worked extremely well.

GE allows me to quickly and repeatedly pan and zoom my map area and evaluate all of these features of interest. With particular reference to the logistics of making a geologic map, I have used GE extensively to quickly trace mappable shorelines, tag key elevations, and decide how (or whether) to group them for mapping purposes. I have also marked some of the more flagrant fault traces to improve the frame of reference for the map. Of course, I have also linked my geotagged set of field photos so that I can get some clear reminders about key areas I am mapping. The map is being compiled in ArcGIS with good imagery (NAIP) and I can simply transfer my interpretations by visual inspection. Of course, I keep turning to GE to check things out in detail because, somehow, the clarity of the imagery far exceeds what I can force out of the NAIP. Likely I will turn the map of this intriguing area into a kml project. Best area yet for that.

Posted via email from Fresh Geologic Froth



  1. If you are drawing lines or polygons in Google Earth, the KML is real data that you can quickly convert into shapefiles within ArcGIS using freely available tools. No need to transfer your interpretations by visual re-inspection of your map.

  2. Sorry–I forgot to include the link:

    • Thanks! I knew this was possible to some extent, but did not know of the Zonums application. Will get right on it and report back on the blog.

  3. As a lapsed geologist, it looks pretty neat what you’re doing. Are any of the representations or models public? If so, I’d like to include a link on the GeoWebGuru forums.

    I would be open to further collaboration as well – send me an email if you’re interested.

  4. I agree, GoogleEarth can be extremely useful (especially in the western states where you lack vegetation)… but “indespensible”? The only indepespensible things required for geologic mapping are your two feet, your eyes, a compass and a notebook. Look at all the wonderful mapping of the old greats such as Richard Jahns (USGS, Stamford) did of sediments *and* crystalline bedrock all over the US with just those tools… in many cases, such maps can’t be replicated or improved upon today…

    • Google Earth is an extremely useful tool. It and other programs of a similar nature (GIS) offer tremendous improvements in our ability to interpret, document, and distribute geologic in a manner far more efficient than the paper map model. It is plausible that tools like this could have greatly enhanced the productivity of accomplished and revered old-school geologic mappers. Of course, nothing beats intellect and experience in developing a good geologic map. Legs are quite useful as well, but some folks don’t have viable legs by reason of time or fate…

      I suppose the I could also claim that oxygen is indispensable for geologic mapping as well…but maybe not on mars…Google Mars is good for that.

  5. … and I must agree, GoogleEarth is starting to beat ESRI’s products in terms of interface and usability. I’m really happy that KML is an open source data format. Many of our map users prefer the data in GoogleEarth as opposed to ESRI format, or even PDF…

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