Nevada Geo-Flood Hazard Map in kml

7-20-2010_2-14-51_pm

Two sweet snippets of a new 15mb kml file that shows the distribution of piedmont and playa flood hazards in Ivanpah Valley, Nevada (just south of Vegas) as inferred from geomorphology. I think that the information content of these types of derivative characterizations of hazards is optimized in Google Earth (or similar virtual globe application). In this case, some arguably arcane geological characteristics are boiled down to a straightforward relative hazard scheme running from cool colors (low hazard) to warm colors (high hazard). The closeup is dominated by the 'Barbie' fan (almost too perfect in shape). It straddles the border of NV and CA. Note how the trunk stream just bisects the Lucy Gray Range...Note that the playa at lower left is the proposed site of a major airport. Yes. That is what I said...Airport.

7-20-2010_2-22-06_pm

The other snip is a sky view of the entirety of the map area with Las Vegas just out of the frame at the top. Just look at that playa (Roach Lake...yes...that is right...Roach Lake). Nice and flat. Just begging for an airport. Such ideas are far from outrageous in Nevada. Go check out area 51 sometime.

Using the transparency slider in GE allows for the user to become familiar with the distinctive surface characteristics of Quaternary desert piedmont deposits (mainly alluvial fan deposits) that inform the hazard interpretation. The high-res imagery available for this area really helps in this regard and completely trumps the overall value of a flat, paper, colored map.
 
House, P.K., 2007, Assessment of piedmont and playa flood hazards in the Ivanpah Valley area, Clark County, Nevada. Nevada Bureau of Mines and Geology Map 158, 1:50,000.
 
House, P.K., Ramelli, A.R., and Buck, B.J., 2005, Surficial geologic map of the Ivanpah Valley area, Clark County, Nevada. Nevada Bureau of Mines and Geology Map 156, 1:50,000.
 
Online report coming soon...seriously.

 

 

Google Earth and LiDAR overlay...Bill Williams River, AZ

Turns out it is pretty darn easy to overlay your spiffy LiDAR imagery
onto Google Earth imagery. Of course, some one had to walk me through
the few steps to take, but soon I will be proficient. Thanks, Heather!

This case is particularly cool because the LiDAR and the GE imagery
appear to show a similar point in time in an otherwise dynamically
changing river. The overlays include a hillshade and a slopeshade.
Both are made slightly transparent to let the 'natural' world shine
through. The mesh of the detailed topography and the details of the
gemorph clearly evident in the imagery is very cool.

These kmz files were created quite straightforwardly using
GlobalMapper. A very, very useful program.

(download)

Google Earth is indispensable for geologic mapping.

9-17-2009_5-35-04_pm

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.


Very Basic Example of a Virtual Field Trip

As I have mentioned in previous posts, Google Map's 'My Maps' feature offers a way to very quickly develop some interesting maps that incorporate images and commentary. This is the most basic application. It is possible to make the interface considerably more elaborate with additional coding using an API--application programming interface. The example below is one that I put together with a few hour's work with photo editing and Google Maps. It highlights some scenic points on recent flights between Reno, Vegas, and Oklahoma City (although the scenery ends near Albuquerque). The potential for this to highlight geologic features of Nevada is obvious, no? It can even be made very technical to share with other scientists. I made mine for fun, but it could be augmented considerably with text on history and geology along with relevant links.

[googlemaps http://maps.google.com/maps/ms?ie=UTF8&hl=en&om=1&s=AARTsJqxy2sRU...,-114.345703&spn=12.185677,18.676758&t=p&z=5&output=embed&w=425&h=350]