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Category Archives: geotag

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

Of all the interesting things I learned at AGU a week or so ago, the utility of the Gigapan system for understanding and illustrating geology sunk in the hardest.

Ron Schott of Ft. Hays State University gave an excellent presentation that made this particularly clear. The gigapan system is elegant in its simplicity and it offers an avenue for simply depicting the elegant complexity (good one, no?) of huge geological vistas and outcrops. It even has an application for looking at very small things in a big way. Check out Ron’s blog for some details.

What is Gigapan? Well, it is a system for taking a panoramic photograph that is composed of many, many, small and detailed photographs. Presumably you have personally attempted to make your own pan photos, say, with a software package or with a built in camera function. Dare I say that you probably didn’t wan’t to try to stitch together more that 5, maybe 6 photos, right? You probably stopped at 3 or 4…like the image below:


The Gigapan cranks this technique up a giganotch by stitching together 10s and 10s of high-resolution images into a…wait for it…Gigapan. The image below is a faked example to illustrate the difference between your approach and the Gigapan approach:


So. Why would you want to do this? Well, for one thing, it is totally cool. For another, it offers an exceptionally efficient way for exploring a large outcrop or geoscape. Once you have taken this series of images, stitched them together, and uploaded the result to the Gigapan site, you can view it at all levels of resolution. In the case above, you can bask in the glory of the huge stack of intracanyon basalt flows on the Owyhee River. Then you can zoom in and look at the complicated cooling structures in great detail. Then you can zoom in and check out the contacts between the flows. While you are at it, you can check out the thin beds of gravels sandwiched between the basalts, etc. etc.

While you are looking at the details, you can pull out images that illustrate some of the aforementioned features. These high-res thumbnails can then be tagged and described for your colleagues to check out. They can then do the same thing and point out obvious stuff that you missed.

I already have my Gigapan gear en route. It works with my existing digital camera collection and is shockingly cheap. Stay tuned for some obvious examples of the application of this to geological studies. Also, stay tuned for the NeGIGAvada project…it is coming. Or should it be GIGAvada?

As a follow-up to recent and elementary post about how useful Google Earth is for field mapping, check out the traverse that I actually made:


Also, check out the online photo album that I created from the geotagged images shown on the snippet above:

Lower Walker River

If you don’t think these technologies are useful, you may need to seek counseling.

Geotagging photos of key outcrops or geoscapes in the field is a very useful thing to do. To geotag a photo is to inscribe the digital file with geographic coordinates. Lots of people are doing it, but I fear that not enough geologists are.

All photo files from digital cameras have an exif header. This stands for ‘exchangeable image file format’ and it is the area where the file name, date, time, exposure, etc., info is stored. Recent interest in digital mapping has lead to the ability to add specific geographic information (i.e. geographic coordinates) to the exif header. This offers great potential to the field geologist. There are various ways to geo-tag a photograph. Up to now, my preferred way has been to use the free photo-sorting program Picasa (yup, a Google product…more on this at related post) wherein you can manually link a photo to a specific location by dragging it to the map. This works fine in many situations, but can be tedious. Over the last couple of days, I have experimented with a more automatic approach using a program called ‘Geosetter‘ which very efficiently and easily geotags my field photos by directly linking their time-stamp with a corresponding GPS tracklog. Brilliant! In this way, you automatically create a geographically accurate set of field photographs. If you use Google Maps, Picasa, or Google Earth, you can then display the images on a base map of your choice.

Check out an example I made using a Picasa Web Album:


http://picasaweb.google.com/drjerque/SpiritMtnNWQuadGeology#

Once at the album, click the ‘view map’ link. Be sure to zoom way in using the satellite mode to fully appreciate how useful this application is. Furthermore, consider the fact that some of your field photos may be of great value to other geologists, botanists, historians, etc., at some point in time. By tagging them with key words, geo-tagging them, and making them available online, you may be doing a great service to other scientists. Burying them in a paper archive or on a CD somewhere does no good.

Note, you can use Picasa to geotag your photos one-by-one through a link with Google Earth, using a simple drag-and-drop procedure. At some point it is obvious that digital cameras will automatically stamp the file with the coords, but I think the linkage between digital photos and a GPS tracklog may be the best way to go.

Are you the creator of an intricate directory structure in which you try to keep track of your digital photos? Have you actually saved multiple copies of a photo in order for it to be represented in relevant folders? I was once such a fool. For several years now, though, I have been using Picasa, a free and simple photo organizing program that allows you to tag your photos with key words instead of storing them in directories with key names. This turns out to be an extremely useful application if you have lots of digital photos. Tagging items with key words is superior to elaborate directory structures. Consider the following situation: You have a photo of a key outcrop in a specific map area that conveys multiple types of information. You can store that photo in a directory that is keyed to that map area and hope to remember that it also contains information relevant to other areas or geologic concepts.

Example from my work: Spirit Mtn. Northwest quad; Colorado River Sediment; Bullhead alluvium; erosional unconformity; sediment sample location.

What to do with this much information? By using tags in Picasa, I can store one copy of this image in a directory of my choice, but then tag it with all of those labels (likely shorthand versions like SMNW; Tcb; Unf; SSamp) so that all I have to do is search on the tag to find the image. Easy? Yes.


Picasa isn’t the only program that does this, but I use it exclusively because I can so easily then link the photos with Google Maps, Google Earth, and any of my blogs (also, it is free). Be sure to check out the related post about geotagging photos and displaying them in a Picasa Web Album. The preceding screen-snag of the interface shows the basic layout. The circled area shows a compass rose icon indicating that the image has been geotagged and an arrow that indicates that it has been uploaded to a Picasa Web Album where the photos can be viewed in relation to the point from which they were taken in the field.

It should take you only 30 minutes to figure out how to use the program. Note that it will automatically search your computer for images and if offers some basic image editing functionality.

Another option for providing spatial context for geologically oriented photographs is to geotag them in an online photo album that links to a map. Here is an example made using Picasa, a very handy (free) photo organizing program that can geotag photos for viewing in Google Maps or Google Earth: Geotagged Photo Example