WHAT NUMBER IS THAT CRS?
by jh, September 25th, 2012
Setting up your Coordinate Reference System (CRS) is an important part of any GIS project. Though Los Angeles County GIS users almost exclusively use a single coordinate system, knowledge of the numerous other coordinate systems becomes essential as one starts exchanging data with other agencies. Luckily, indexed lists have been created that assign unique numbers to each geographic or projected CRS.
The Federal Information Processing Standard (FIPS) is used to identify State Plane coordinate zones by ArcGIS, the NGS Toolkit, and Corpscon 6, while the European Petroleum Survey Group (EPSG) index is used by popular open source GIS applications.
As a resouce, some useful links are listed below:
EPSG Registry is worth bookmarking!
NGS Geodetic Toolkit includes a Find Zone lookup page.
Corpscon 6 is popular among surveyors and mappers for coordinate conversions. Note Instructions for Windows 7 users.
California Public Resources Code, Section 8801-8819 is your legal reference. Definitions for each Zone in California are included here.
ArcGIS 10 Help is an excellent source for background information on State Plane coordinate systems.
Spatialreference.org is another must-bookmark for its speed and simplicity.
Just for fun, go to Spatialreference.org and enter “0405″ into the search box. Select the result “ESRI:102645: NAD 1983 StatePlane California V FIPS 0405 Feet”. Selecting this link takes you to page that allows you to download sample projection files. “Google it” takes you to where you can learn more about that projection.
FIPS 0405 represents NAD 1983, State Plane California, Zone 5, US Survey Feet.
MAP MATTERS!
by jh, September 25th, 2012
Using Web Map Service (WMS) layers is a great way to exchange GIS data on the web! Like a child playing with Tinkertoys, all of us can easily assemble maps from free online data sources.
Unfortunately, WMS layers may become unavailable without warning. It’s painful when your GIS software freezes up when your GetCapabilities document isn’t there.
Luckily, mapmatters.org monitors thousands of WMS layers. The site is a valuable resource for testing and searching for new WMS URL’s.
DEFINING ‘OPEN’
by jh, July 9th, 2012
ESRI continues to reach out to the Open Source Community (or, at least to ArcGIS users considering open source GIS applications) in their current edition of ArcUser magazine. The article, Defining Open, does a pretty good job of explaining Open Source, Open Data, Open Systems, etc., providing brief descriptions on each topic.
In the latter paragraphs, ESRI reminds us that they are contributors to open source software, announcing that they are “… planning to release the source code for the ArcGIS for iOS and ArcGIS for Android mobile applications as open source software soon.”
Is ESRI is releasing their mobile apps? To learn more exciting news, the article directs us to visit esri.com/open.
PEACE, LOVE, AND… THE GOOGLE SUMMER OF CODE!
by jh, June 19th, 2012
Larry Page, one of Google’s co-founders, once observed that not enough college students were spending their summers writing computer code. He felt that a lot of time and talent was being wasted by students flipping burgers or other odd jobs during their university summer breaks. A solution to this problem was to award money to talented students working on worthwhile open source projects. The Google Summer of Code (GSoC) was born! What else can be a better resume builder?
There is a half-hour YouTube video that provides further background, history, and tips for students betting accepted.
OSGEO is a worthwhile DOT-ORG with its own GSoC web page. Note the Ideas Wiki Page for this summer’s improvements on different open source GIS projects. Best of luck to the 22 students who were selected!
Note: YouTube links may be blocked by your network, even if they are embedded – you may need to view videos at home…
GRASS (Geographic Resource Analysis Support System)
by jh, February 21st, 2012
GRASS is the granddaddy of all open source GIS applications. With roots almost as old as ESRI’s ARC/INFO, it was originally developed by the U.S. millitary as a tool for managing millitary-owned lands in the early 1980s. Today, GRASS’ software development is managed by a multinational team, licensed under the GNU General Public License (GPL).
GRASS is free, powerful, and contains over 350 programs and tools for managing and analyzing data. There is a learning curve for first time use; luckily, an online tutorial is available at http://geostat-course.org/Topic_NetelerMetz_2011.
The accompanying lecture videos are available at
http://www.archive.org/details/GeostatSummerSchoolGrassGisTutorial
Official site: http://grass.fbk.eu/
Wikipedia: http://en.wikipedia.org/wiki/GRASS_GIS
GEOTAGGING and the EXIFTOOL
by jh, January 23th, 2012
As GPS-enabled cameras and smart phones continue to be more commonplace, GIS users will see increased requests to create maps from geotagged digital photos. Digital photos contain numerous pieces of information, or tags, that are embedded by digital cameras as pictures are taken. One of the most powerful tools for working with these tags is the free ExifTool by Phil Harvey.
To use ExifTool, download the Windows executable (currently exiftool-8.76.zip) at http://owl.phy.queensu.ca/~phil/exiftool/.
Once extracted, rename the file exiftool(k).exe to just exiftool.exe and place it into a folder where it will be used. (If you plan to use this utility often, consider setting it up in the path.) Open the Windows Console and navigate to that folder.
Below are some sample Console commands:
exiftool [Running exiftool by itself prints ExifTool help to the Console screen]
exiftool Photo1.jpg [This gives you EVERYTHING in the file Photo1.jpg]
exiftool -s Photo1.jpg [Gives you the same info with actual tag names in stead of descriptive tag names]
exiftool -GPSPosition Photo1.jpg [Gives you GPS coordinates in that file, e.g. 39 deg 44' 18.59" N, 104 deg 59' 13.39" W]
exiftool -GPSPosition -n Photo1.jpg [Gives you coordinates in a numerical format. e.g. 39.7384972222222 -104.987052777778]
ACCESSING MULTIPLE BLOGGERS
by jh, December 26th, 2011
One online resource that accesses seven blogs at once is Quantum GIS Planet. You can review the Blog List, or click any of the numerous links under “Tags”.
For example, click “3d” to read tips and tricks about using QGIS to visualise GIS in 3D from multiple bloggers. Though extremely convenient, this site should not be your one and only stop. A Google search got me this Linfinity blog on 3d QGIS that was not included. Keep an open mind; the “Planet” is a must-bookmark.
INTRODUCING OSGEO!
by jh, December 20th, 2011
From their website, the “OSGeo was created to support the collaborative development of open source geospatial software, and promote its widespread use.” A presentation at slideshare.net offers a useful summary. They also offer resources, including a book list.
OSGEO also sponsors the annual FOSS4G (Free Open Source Software for Geospatial) conferences, with FOSS4G 2012 being held in Beijing, China next September. No plans to go to China? No Worries! There is plenty of talk on open source GIS software at CalGIS 2012 in Sacramento in April.
FOR QGIS USERS
by jh, December 5th, 2011
A useful resource for Quantum GIS (QGIS) users is the Linfinity Geo Blog. This site contains numerous ‘how-to’ blogs and articles. Don’t forget to include “Linfinity” in your Google searches when you are looking for QGIS fixits!
The same people host an online training site complete with videos, etc.
ESRI and OPEN SOURCE: US vs THEM?
by jh, November 28th, 2011
There are at least a few of us who like to talk about saving money by integrating open source GIS applications into our daily mapping operations. That’s a mouthful.
Read this Esri Insider blog post by Victoria Kouyoumian, Esri IT Strategies Architect. To keep abreast of ESRI’s open source efforts, visit or bookmark their open source page at esri.com/opensource.
GIS BOOK REVISED, and a GIS BOOT CAMP?
by jh, November 21st, 2011
For anyone new to open source GIS applications, a very good start is the book Desktop GIS: Mapping the Planet with Open Source Tools, by Gary E. Sherman. Currently this 2008 book is out of print, but wait! A new edition is to be released in early 2012!
Chapter excerpts are available: see “Working with Vector Data” and “Data Formats”.
For those who want to dive deeper, there is an Open Source Bootcamp for developing web based GIS applications. The online training event starts in January 2012, and there is a discount for signing up before November 30.
THERE ARE A LOT OF OPEN SOURCE GIS APPLICATIONS!
In January 2012, this web page was getting a little large and cumbersome to edit. To make room for more entries, some housecleaning needed to be done. To see the LARGE LIST of open source GIS applications that was listed here, please visit http://opensourcegis.org/.