GISCafe Weekly Review October 17th, 2013

Moving the Nation’s Natural Gas
October 17, 2013  by Ryan Hamilton

Land slip risk assessment as a means of highlighting buckling and cross slope threat

A couple of weeks ago I had a mountain bike race in one of my favorite places in the world: Moab, Utah. The race went okay despite destroying a shock, rear derailleur, and my rear wheel. Even for a hack like me, that is a significant list of parts to go through in just three days of riding. The fact is that southwest Utah is a rugged place and it’s hard on equipment, which is why I was intrigued by a new natural gas pipeline being built along the Interstate 70 corridor. If you were to view this pipeline project in just one spot it might not seem all that impressive; it’s just a 2-foot wide by 8-foot deep trench with a green pipe being laid inside. However, when you observe it for hours on end outside your speeding car window, snaking along for hundreds of miles through the rugged and formidable Moab desert, you get a real appreciation for how monumental a task this project really is. Considering 60 miles of bike riding in Moab all but destroyed my bike, I have to imaging the equipment used in this build project will most likely be scrap metal by the time the pipeline is completed.

I want my data
October 15, 2013  by Ryan Hamilton

Access to data has never been easier. Web services and cloud storage have allowed a new level of access to geospatial data that would have been unimaginable 10 years ago. One of the hottest resources for getting data now is WeoGeo.

Promotion and sales are easy for data suppliers who can easily go to the WeoGeo marketplace and have their data reach millions of professionals. WeoGeo filters the available data depending on an area of interest and the data type that the buyer wants. As more and more suppliers and vendors join onto the WeoGeo marketplace, the geospatial world gets closer to a true one-stop data shop. Besides the convenience and ease of getting the right data, access to geo data has also become more economically friendly.

SAR Imagery: Is there a way to focus it?
October 15, 2013  by M. Lorraine Tighe, PhD

Synthetic aperture radar or SAR imagery can be challenging for non-radar geeks to figure out what exactly the SAR image is illustrating. Of course our eyes have little trouble understanding aerial photo images primarily because the cameras used to collected photos operate at similar wavelengths (located in the visible portion of the electromagnetic (EM) spectrum) to our eyes. SAR sensors on the other hand, operate in the microwave portions of the EM spectrum which is very different from how our eyes see.

Take a look at the regions of the U.S. that have been most heavily impacted by the government shutdown on Esri’s interactive   Federal Government Shutdown Map This map uses data from Trulia.com to show the 10 areas in the US that have the highest percentage of local wages going to federal workers. You can also explore demographic data from Esri that compares median household income and unemployment in these areas to the national average to better understand the local impacts of the federal government shutdown.

High Accuracy Terrain Models Using Advanced Elevation Series
October 14, 2013  by Jennifer Shaffer

Are you still using coarse resolution SRTM elevation data for your geospatial projects?  Are you struggling with coverage, quality problems, and data gaps? If so, it’s time to learn more about DigitalGlobe’s comprehensive elevation offering called the Advanced Elevation Series. With accuracy and resolution options to fit your project and budget, DigitalGlobe can provide the terrain data you need for accurate 3D mapping and analysis.

Many geospatial professionals often waste excessive time searching online for free elevation data that includes the coverage, accuracy and resolution qualities they seek. Then after squandering time on these datasets, they find the data to be inadequate or requiring significant editing to be usable.  Many geospatial professionals are unaware of what’s available commercially. Commercial data that is GIS-ready can save users time and effort and are dollars well-spent.  By eliminating data preparation work, users can focus on creating the maps and delivering the answers their organizations need.

GIS Has Never Been More Affordable
October 14, 2013  by Matt Sheehan

GIS was once a technology used only by those with the deepest pockets. Today things have begun to change. In this post we will discuss 3 ways GIS is now more affordable, for big and small organization alike.

Low Cost Web and Mobile GIS Apps

Go back a few years and the cost of Web and mobile GIS apps was sky high; $20,000, $30,000 … And that was just for the application, add ArcGIS server or equivalent to the mix and costs could easily push north of $50,000. Today all that has changed. Web and mobile applications are now easier to build. The emphasis has been on simpler, more intuitive GIS apps. Those built to provide a specific purpose, maybe data collection, map annotation, dashboard or routing. Gone are the days of bloated expensive applications loaded with tools. There are now many free apps available. Esri’s mobile Collector app is one example. In addition many basic application frameworks have been released which can be extended. No more reinventing the wheel. At WebMapSolutions we have been extending our own and others frameworks to simplify and reduce the cost of Web and mobile application development.

Topography plays an important role in the distribution and flux of water and energy within natural landscapes. Increasing quality and resolution of elevation information, new processing methodologies, and expanding GIS capabilities and linkages with water resources models are expected to lead to a heavier reliance on elevation data as a source of topographic and surface drainage information.

The capabilities and limitations of elevation data for use in watershed management applications include, but are not limited to: elevation data availability; elevation data vertical and horizontal accuracy; quality of the available elevation models to provide topographic and drainage information; requirement of the scale of the modeling of catchment basins; and ability to assess risk associated with flooding. The characterization of elevation data quality and the association between topography and water resources models is related to the grid sample distance (or resolution) and the vertical accuracy of the elevation data used. Moreover, the quality of readily available elevation data, varies from source to source in terms of horizontal resolution and vertical accuracy which are the two important aspects of elevation uncertainty in the modeling with raster GIS. Often times, however, the choice of elevation data (sample elevation data are illustrated below) selected will depend on budget, ability to process and analyze data, the capability to generate the necessary answers needed for a project and the mapping scale of a project (e.g. mapping scales may correspond to 1:5,000 (small village, NEXTMap 5m), 1:10,000 (town; NEXTMap 5m), 1:20,000 (large county ASTER or World 30m), and 1:50,000 (a nation; World 30m or SRTM 90m)).  A few examples of elevation GSD and vertical accuracies are presented here.

Topcon
Trimble – Terraflex
Optech - Intergeo


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