“Creating an interactive census map is easy using the free GeoCommons map service. This video tutorial takes you through the process step-by-step. You will download map files from the U.S. Census Bureau Tiger Shapefile Library, download and edit population data from Bay Area Census and merge the two to make an interactive map that you can publish on your site.”
If you haven’t had a chance to checkout Google Refine…what are you waiting for? This data tool is great for helping to organize and clean all types of data. Here is an example of how you can use it to geocode a database of addresses. Refine allows you to use Google’s Geocoding API to find the lat and long of your addresses.
The AfghanistanElectionData.org website shows off some pretty impressive analysis and map visualization of election results in that country. I wish there was more of this going on.
For those GIS peeps who are also Mac users, and in need of computer-aided drafting software to help out with three-dimensional modeling or maps, Autodesk is back in the game after a nearly 20-year hiatus from the platform.
AutoCAD Map 3D
AutoCAD for OSX is available on as a trial for all users, and free for the educational user. The upside to creating an account is access to additional software, offered under similar terms, such as AutoCAD Map 3D (Windows only). Autodesk further affirms its commitment with a new AutoCAD application for the iPhone.
Between the two applications, which can import ESRI shapefiles and digital elevation models as well as the usual DWG, users are able to perform a great deal of heavy lifting in GIS visualization and join topographic features and imagery with urban planning info.
An overlay is an image layer that is built or added using KML to display on top of the basic satellite imagery in Google Earth or Maps. Overlays are used to further describe topology or illustrate information.
Ground overlays are images that are displayed on the terrain at ground level, or at an altitude (specified in the KML) above the ground surface. These can be satellite photos, or generalized color bands to display gradient information. Earth browsers that support KML will support ground overlays using the standard image file formats.
Photo overlays: In other GIS applications, this would be generally referred to as an orthoimage, and is rectified, or corrected, for accurate geographic measurement. Photo overlays allow users to further explore the area in detail. Google Earth supports the use of panoramic presentations in its photo overlay scheme.
Screen overlays are two dimensional images that are attached to the forefront of the display, and are used for map legends and logos.
In KML, each overlay type is given properties that describe color and transparency (using hexadecimal value), icons (to display various map elements, such as placemarks for points)and draw order (for images that overlap or stack).
I’m always amazed at the free mapping tools that are now available to journalists. Would have loved to have some of these tools when I was working in the newsroom. Pete Warden has developed OpenHeatMap as personal project to provide an easy way to build storytelling maps. The service is designed to make it easy for people to create and share choropleth and heat maps. It transforms data from a traditional data source such as a spreadsheet into an interactive animated view of a particular area. You can then share that map online, a bit like YouTube for geographic visualizations.
Here are some examples:
He even targets journalists in this video tutorial:
Only a few years in use, Keyhole Markup Language has become a popular addition to geo-visualization and notation.
The KML Handbook: Geographic Visualization for the Web is a good starting place for learning about this popular GIS markup language.
KML is XML-based and describes geographic attributes for visualization on Web and Earth browsers. Because it is an XML-based language, KML is largely human readable and can actually be written quite simply by hand using a text editor, or can grow more complex in which case you will want to turn to additional utilities for help.
The structure of KML specifies points, lines and polygons, and geo-location, much as ESRI’s shapefile describes layers, but is not limited to only one type of vector. In addition, KML includes references for tilt, heading and altitude, as well as annotation for reference about the location, photography or links to outside information. The file is then rendered superimposed on a map (such as Google Maps) or an Earth browser (such as Google Earth).
You can easily view the schema by opening a .kml file with a text editor. What you see will look similar to this:
KML’s foundation in XML makes the format easily generated and distributable on the web. Custom styling for markers, icons and images can be inclusively written into the markup code, to be hosted centrally or distributed with the file. Such a distribution is usually zipped as a KMZ. As mentioned, KML can be written manually using a text editor, or drawn using utilities or a browser such as Google Earth. With a server setup, KML can be generated using scripting languages, such as PHP, allowing on the fly exports of updated information based on user interaction. ESRI’s ArcGIS is also capable of exporting shapefiles to KML.
The advantage for journalists is that KML provides a fairly easy and quick solution (and arguably universal on the web) for creating sophisticated and aesthetic maps, using freely-obtained tools. Google Earth allows the user to import spreadsheet data for display, and then export as KML for distribution or to embed on a website. (more on this). The limitation or disadvantage here is that KML is only a means for distribution and display, and not at all a RDMBS — the analysis must be done on the spreadsheet. While it is conceivable that KML could at some point be used to conduct spatial analysis like more sophisticated GIS options, none exist that I know of (correct me if I’m wrong).
