Since the last time I wrote about how to use BatchGeocode.com to perform pseudo-geocoding tasks in QGIS, there have been considerable improvements in the multi-platform, free, and open source GIS software. Now, geocoding (turning addresses into coordinates) is more automatic, albeit difficult to setup. (Okay, this has been around June 2009 and I just found out about it in October 2010.)
Once you install all the components, you’ll never have to do this again.
This method can only geocode one address at a time, but it will geocode all of the addresses into a single shapefile.
- Download QGIS.
- Download and install Python SetupTools. This includes the easy_install function that will download a necessary Python script, simplejson. On Mac you will have to use the Terminal (Applications>Utilities). Email me if you run into problems.
- Install simplejson. In the command line (Terminal for Mac; in Windows press Start>Run>”cmd”>Enter), type “easy_install simplejson”.
- Download the GeoCode plugin by Alessandro Pasotti via QGIS>Plugins>Fetch Python Plugins. You may have to load additional repositories to see it.
- Install geopy. In the command line (like step 3), type “easy_install geopy”.
- Specify your project’s projection in File>Project Properties.
- Get a Google Maps API key and tell the GeoCode plugin about it (QGIS>Plugins>GeoCode>Settings). You will need a Google account. If you don’t have your own domain name, you can just enter “google.com” when it asks for your domain.
- Geocode your first address by clicking on Plugins>GeoCode>Geocode. Type the full address (e.g. 121 N LaSalle Street, Chicago, IL for City Hall).
- The geocoded address will then appear in your Layers list as its own shapefile. All addresses geocoded (or reverse geocoded) in this project will appear in the same layer (therefore same attribute table).
Once you install all the components, you’ll never have to do this again. Geocoding will be available each and every time you use QGIS in the future on that workstation.
- When you’re done geocoding, Â save your results as a shapefile (right click the layer and click “Save as shapefile”). Twice I’ve lost my results after saving the project and quitting QGIS. When I reopened the project, the results layer was still listed, but contained no data.
- Add a “name” column to the GeoCoding Plugin Results layer’s attribute table (toggle editing first). You can then type in the name of the building or destination at the address you geocoded. Edit the layer’s properties to have that name appear as a label for the point.
A map I made with QGIS showing three geocoded points of interest in Chicago. Data fromÂ City of Chicago’s GIS team.