ArcGIS ModelBuilder tutorial

I have written a short ModelBuilder tutorial that shown how to use an iterator to automate a repetitive process – converting a number of polygon feature classes to rasters in a geodatabase.

If you are interested in learning more about what can be done with the ModelBuilder, explore the ArcGIS Help files (search for ModelBuilder) and work through the two tutorials, or request a code to take the ModelBuilder course from the Virtual Campus.

Introduction to GIS course – first module

I am working on developing a series of self-paced GIS training modules. This first effort is designed for users who have never used ArcGIS before, and is a very simple introduction to using ArcMap.

The data are available to download here.

There is also a link to the data download in the exercise.

More updates and material to follow… You will need access to ArcMap 10.1 and have an Internet connection to complete this module.

An interesting discussion on how software bugs are identified

A user forum thread at ESRI about crashing issues with ArcMap 10.1 SP1 sheds some light on how bugs are identified. Reply # 55 lists the answer.

Apparently ArcMap 10.1 has some issues with stability when the Georeferencing toolbar is open and a large number of rasters are present in a map document. A fix is planned for ArcGIS 10.2 (coming this summer, perhaps July of 2013?) but some workarounds are listed in the discussion.

ArcGIS for Desktop – “Tool not licensed” error

If you receive a ‘tool not licensed’ error when trying to use an ArcToolbox tool from an extension (Spatial Analyst, 3D Analyst, or others) then it’s likely you have not enabled the extension before trying to use it. If the extension has a toolbar, making it visible is not the same as enabling the extension.

Note that the error message states no… “license currently available or enabled“. The default install of ArcGIS includes all extensions, so it’s likely not enabled if you’re seeing this message.

To remedy this, open the Customize menu and choose Extensions…

Check the box for any extension you wish to use, and click Close. Try re-running the tool and it should work. To verify if a license is available, open the ArcGIS Administrator and select the Availability panel. Extension licenses will be listed below ArcGIS…

How to update an ArcGIS student edition license

If you are running your own copy of ArcGIS – the Student Edition – the license is valid for one year. It is possible to renew your student license without re-installing ArcGIS or obtaining another install DVD. You will first need to get a new registration code. These are available by sending an email to it-help or to mdhyslop at

Detailed instructions for activating your license are available as a PDF: How to update an ArcGIS Student Edition license.

Please email mdhyslop with questions or comments.

A new look at the election map

Many of you have probably seen one form or another of the U.S. election results maps in the last decade, showing red vs. blue states (or counties), with areas won by the republican candidate shaded in red and those by the democratic candidate in blue.

State by state U.S. Presidential election results, 2012

It’s easy to be ‘misled’ by a map, however, in this case because the colors are applied to states that have very different characteristics (area, total population, population density, and population distribution). The red – vs – blue areas appear to be about equal (and it was a close election) but the map is not as factual as it could be. Is it more accurate to show results on a county by county basis?

County-level results for the 2012 U.S. Presidential election

On this map, the red areas vastly outnumber the blue, giving the appearance of a republican victory. Clearly, looking at the results using counties instead of states does not produce a more accurate map. What’s missing? Population density.

Election results mediated by population density

Election results mediated by population density.

In the above map, the darkness of each color indicates how densely populated a county is. The vast areas of the Great Plains are very sparsely populated, appearing almost white in some parts, whereas the urban centers on the west and east coasts (look at Long Island), as well as in the Great Lakes, have much higher populations and are therefore very dark.

If you are interested in seeing more examples of these maps, I suggest you explore the article showcasing the population density map at The Atlantic Cities, Mark Newman’s election web site (U of Michigan), or Robert Vanderbei’s maps of the 2012 election (Princeton). At these sites you will find cartograms, county maps shaded to show voter split (purples where the vote was close to 50-50), animations, and more.