26/3/2012

Introduction to open-source GIS tools for journalists

 

Originally published by Matt Wynn on poynter.org on 19 September 2011. This excerpt is republished with permission. 

 

For years, it’s been only the most committed of journo-nerds who could invest both the time and money to put geography to use.

To say that’s changing is an understatement. GIS (Geography and Geographic Information Systems) is quickly becoming an integral part of how journalism is created and delivered.

Location is one of the key components of mobile, allowing information to be filtered based on location. It’s the foundation for pioneering concepts like EveryBlock and the reason most news organizations are enamored by geocoding news items. Geography is even a feature of Longitude, one of the inaugural projects of the New York Times’ beta620.

Luckily, as the need for geographic literacy has increased, digital cartography has exploded. Interactive maps and location-based services have unleashed a torrent of spatial tools throughout the past few years, making everything from analysis to sophisticated Web applications accessible.

There are a bevy of tools available, but here’s an introduction to those that make up my open-source GIS suite.

Getting your feet wet: QGIS

Journalists mostly use GIS systems to map and layer different data sets. Typically, these data sets come as “shapefiles” — geographic databases that contain points, lines or polygons, as well as information about each feature. It’s a fairly open standard that comes from a commercial background.

Even non-native GIS databases can be mapped through geocoding, whereby addresses are plotted on a map. Just a few years ago, the process was a headache that could last for days. Now, thanks to tools such as Google Fusion Tables and Refine, it’s a lot easier.

You can compare geocoding results, satellite imagery and shapefiles to one another to reveal all sorts of things: how lottery sales relate to poverty; how well a county’s tornado sirens cover the population; or that minority neighborhoods are more at risk of foreclosure.

ArcView, one of the most well-known proprietary systems, remains the industry standard for GIS. You probably even have an installation in your building — if not in the newsroom, then perhaps in circulation or advertising.

Some newsrooms worry that without ArcView, their spatial capabilities are limited. Fear not: QGIS has quietly come of age. Over the past few years it has become easier to use and far more powerful. It’s now a more than worthy replacement for the old ArcView standby.

There’s no dearth of resources for getting your feet wet with spatial analysis in QGIS. Here are a few links to get you started:

  • The QGIS wiki has walkthroughs and video tutorials for everything from opening shapefiles (vector files) to handling projections, a term I never thought I’d deal with outside of sixth-grade social studies.
  • Data analyst Tim Henderson wrote an excellent tutorial to making quick interactive maps using QGIS and some javascript libraries.
  • Michelle Minkoff has done a number of posts on getting spatial records — like those managed with QGIS — online with tools from Google. Here’s one looking at intensity maps.
     

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Read the full article on Poynter.org.

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