Wednesday, September 1, 2010

This blog has run its course.

The Nevada Digital Dirt Mapping Project Experiment is over. Our mapping team demonstrated that it is feasible to develop a 1:150,000 scale surficial geologic map of 20,000 square kilometers in 18 months. Our approach represents a valid model for collaboratively developing geologic maps of large areas in short periods of time.

Thank you for your interest in our endeavor.

Tuesday, June 29, 2010

Wow. I may just get my life back soon.

Maybe some real sleep too. Over-dedication is over-rated. Now I know for sure.

Posted via email from Fresh Geologic Froth

So, this happened.

A big day for the is complete enough to submit. In
celebration, I urged a colleague at a similar institution to help me
go live with the map.

You can temporarily view it here:

Now, to finish that darn report by 3 PM tomorrow.

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Monday, June 28, 2010

1000s of miles of lines...

The colorful map shows the compiled linework that we started with.
Much was extensively modified to better illustrate the array of
surficial geologic deposits. The redline map shows the final
(preliminary) result of the modification and the addition of many,
many, many additional lines. Note that we simplified the bedrock.

Thus, some of the line density decreased as well.

Posted via email from Fresh Geologic Froth

Three representations of the Clark County DirtMap

Illustration of progressive levels of generalization...from most
detailed, to genetic category, to fundamental category.

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Friday, June 25, 2010

Holy freaking crap, it's a freaking map!

See a mistake? Keep it to yourself. Our team collectively put a few 1000 hours into this product. It is the only complete map of the surficial geology of Clark County, Nevada that you are going to find.

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The Dirt Map Correlation Chart....Revised

This is getting closer. Have had to impose a moratorium on additional mapping at 3 PM tomorrow. today. Working on the report.

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Thursday, June 24, 2010

The Dirt Map Correlation Chart....

This is getting close. Have had to impose a moratorium on additional mapping at 3 PM tomorrow. Working on the report.

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Tuesday, June 22, 2010

Clark County Mega-map: One week to go...

There are no perfect maps. Trust me, there truly aren't.

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Monday, June 7, 2010

Nevada Digital Dirt Presentation

The_Nevada_Digital_Dirt_Mapping_Project.pdf (4007 KB)
View this on posterous

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Friday, June 4, 2010

State of the Clark County map, June 4, 2010

Bear with me here. This one clearly demonstrates the progress to date by showing all of the units we have divided. Less than a month to go...oh right, with 7 days of field camp in the middle. Wish us luck.

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Tuesday, June 1, 2010

State of the Clark County map, June 1, 2010

The map just keeps getting better. Tying up some loose ends, dealing differently with the Muddy Creek Formation, addressing some reviewer concerns based on a much older version, etc. Presented this map at the Digital Mapping Techniques Workshop in Sacramento a couple of weeks ago. Reaction to talk and map indicates that this map was made in record time for a record bargain.

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Wednesday, May 12, 2010

The Clark County 'Dirt' Map: Only 16.5 months in the making....1.5 months to go.

Despite combining this monsterous map with just a few other mapping 'efforts' this thing may actually get finished! 

Note that this is the generalized version. Still working on the detailed version. Will be describing this project and the value of 'supervised Crowd-sourcing for rapid geologic map development' at the Digital Mapping Techniques workshop in Sacramento next Monday.

Nevada Digital Dirt Mapping Project Team members:
Rachel Wearne
Larry Garside
Alan Ramelli
Joanna Redwine
Ronna Bowers
Jason Man
Michell Rose
Luis Rodriguez
Molly Hunsaker
Dan Kozar
Rohit Patil
Justin Skord
Jim Trexler
Pat Cashman
Jill Heaton.

Yes...there are some problem areas. Relax. We know about them.

Posted via email from Fresh Geologic Froth

Saturday, May 8, 2010

State of the Map: Clark County, NV

Again, significant progress to report. Thanks to Dirt Mapping team
co-leader Heather Green for keeping things in line while I panic about
too many other projects.

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Wednesday, May 5, 2010

Clark County Seven Ways

An example of the array of base imagery that we are using to build the
surficial geologic map of the county. Some look far better (and some
far worse) at larger scale.

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Friday, April 30, 2010

State of the Map: Clark County

Major progress to report. One version is the generic unit map, the
other (messier) version is the more finely divided map.

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State of the Map: Clark County Lines

Posted by Picasa

Friday, April 23, 2010

State of the Map: Clark County, Nevada (2)

Immediately following the previous post, I got this image from the
team's co-leader. This one portends the diversity in the final map
that we have planned.

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State of the Map: Clark County, Nevada

The clean version indicates the huge progress that we have made in
developing the generalized map. The 'messy' version portends the
variety of alluvial fan deposit (mainly) that we will soon be
beginning to methodically attribute and carve-out (where
necessary) to create the finished map.
Hooray for the Nevada Digital Dirt Mapping Team!

Tuesday, April 20, 2010

State of the Clark County (Nevada) Map

Huge progress in last two weeks. Leveraging the skills of multiple
users in ArcSDE...would be dead without it. A viable example of
'supervised' crowd-sourcing of geologic and gis expertise.

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Friday, April 16, 2010

Editor Tracking Tool in ArcGIS.

Presently, I am trying to manage 9 mappers working simultaneously on the Clark County surficial mapping project...the number may swell to about 12 or 15 in the next week or so. This effort is being made possible by using ArcSDE...there is really no other way to do such a thing efficiently...more on that later.
Recently, we discovered an editor tracking tool that can be installed that provides records of who edited what and when. We found it quite late in the game, but now that we have had it for about 3 weeks, it provides a useful and promising perspective on the progress with the map. Each line that is touched by an individual and edited in some way (no matter how small) becomes tagged with that person's ID. Looking at the map symbolized by mappers is interesting, shows progress, and also...well...lets you hone in on potential trouble spots. Also, the fact that if an editor touches a very long line by fixing only a small segment helps motivate the individual to investigate the entirety of the line. Sweet!
The tracking tool can be downloaded from ESRI at:
Here is an example that shows the tool's results as well as some serious progress on this huge, huge, huge map. Did I mention that the map is huge?

Tuesday, March 2, 2010

Slopeshade v. Hillshade for bedrock contact mapping

The Digital Dirt Map of Clark County, Nevada is proceeding with a team of 13 now. The goal is to complete the map by May 1 (!), so the team may grow by a couple more members soon. One of the key issues that we are currently grappling with is the refinement of the bedrock-alluvium contact in areas where it is poorly expressed by existing sources. For the most part this includes areas previously mapped at only 1:250,000 scale. Areas previously mapped at smaller scales (1:100,000 and 1:24,000) are far less problematic.

Accurately mapping this contact for a final scale of 1:150,000 for our compilation requires some basic approaches. For one thing, I have been actively training a capable team composed primarily of geography and geology students, so the learning curve isn't too steep.  To discern the primary contact, we have multiple base sources at our disposal (e.g., ASTER, NAIP, ETM) as well as a nice hillshade image of the county based on the 10-m DEM data. This particular base image alone allows for a massive improvement in some of the preexisting geologic linework on the basis of distinguishing predominantly steeply sloping and irregular bedrock outcrops from less steep and generally smoother alluvial, aeolian, and playa deposits. However, applying a manipulative trick that maximizes the value of LiDAR imagery for topographic visualization, it is possible to leverage even the 10-m DEM for better results.

The approach is to develop a slopeshade map. In the case of a slopeshade map, all steep slopes are shaded and all gentle slopes are matter what their aspect. It is essentially an isoshade representation where the sun is shining from all angles at once. 

Here are some examples with the 10-m Clark County data, starting with the hillshade:
Looks nice, no? This is a very pleasing way to present the county in cartographic form.

Here is the slopshade version of the same data:

It is quite stark in comparison, but it conveys the topography in a very useful way. Consider the smaller scale versions of the Arrow Canyon area presented below:

The Hillshade version:

The slopeshade version:

Note how different these two images are. In the case of the slopeshade, no topography is masked by shadow. Every slope is rendered in the same way no matter which direction it faces. In this rendition the primary contact between rock and non-rock is quite clear.

For more examples and an explanation of how easy it is to derive this type of image, check the following links:

Happy mapping!

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Monday, February 22, 2010

Nevada Digital Dirt Team undergoes major expansion

Over the past several weeks, I have initiated a major expansion of the Dirt Mapping Team. Completing such a large map by the beginning of May (!) is a mammoth undertaking. As the previous post indicates, we have made significant progress, but it has become clear that the active mapping team was too small (essentially, two of us). The increase in membership has been greatly facilitated through direct cooperation with the affiliated ecosystem mapping and GIS team from the UNR G-lab, and from some 'hand-picked' UNR geology students and profs with skills in mapping and GIS. 

Thus, we now have up to 11 contributors performing at various levels and time commitments. Currently, our main tasks are improving existing linework from compiled map sources and dealing with mapped units that are below our minimum map unit threshold. The first step in the linework improvement phase is modification/reshaping of the contact between bedrock units and surficial units. This turns out to be the easiest step for new 'recruits' to understand and master. The process is greatly enhanced by including multiple imagery types and shaded relief models as base layers which allow for different, yet complementary perspectives on the landscape. Also, running Google Earth in an adjacent monitor is also quite handy. Oh right...the G-Lab also got some sweet new Wacom digitizing tablets as well.

We are using versioned geodatabases in ArcSDE. to allow for independent and concurrent editing among all of us. This is the best scenario for a multi-mapper effort. Thanks to Abbey for managing the whole affair.

The ideal trajectory of mapping participation is as follows:

1. Contact between bedrock and surficial deposits (currently underway)

2. Contact between different master classes of surficial deposits (e.g., alluvial fans from playas, etc.)

3. Contact within master classes of surficial deposits (e.g., alluvial fan deposits of different ages)

Progression through these steps will depend in large part on performance and time available to map. Most team members have been assigned a 15' by 15' (minutes of lat and long) cell in which to work on the bedrock contact. They are tracking their time. Every cell will be evaluated for consistency and accuracy by the team leaders. 

To date, I have spent several hours providing tutorials about the most efficient ways to carry out the bedrock / non-bedrock contact and will spend some more time this week to make sure everyone is up to speed. Also, several times in the last few months I have been able to provide some instuction / explanation in the field about the nature of the deposits we are mapping. 

Monday, February 8, 2010

Generalized map of surficial and bedrock units as of February 2010

The Clark County dirt mapping team will soon expand from 4 to 7 or 8 as we approach a key deadline. The morass of linework remains a major issue, but we are slowly refining it into a clean data set. Here, I thought I would take a step back and evaluate the map on a more fundamental level...that of key mappable unit types. Much of this map reflects the original data sources that we are refining, but it provides a very nice overview of the distribution of the key map unit types in the county. The deposits are not divided by age in this rendition...just process / deposit type.

As the full team begins to take on the county en masse, I will post updates of this particular representation as it evolves.