Tag: Maps

Google Maps, the dynamic GIS system

November 27, 2009 / / 0 Comments

Earlier this year, Google Maps added a feature to the common maps interface that allows users to identify problems* with map data or presentation. Click on the “Report A Problem” link in the lower right corner of the current map view. Then drag the marker on top of the error, categorize it, then write a description of the problem.

I reported several problems soon after the feature was released. I checked up on the results of one problem I reported. The situation was the lakefront multi-use path along Lake Michigan in Chicago, Illinois. The screenshots below show the map before I reported the problem and the repaired map.

With this addition, Google Maps seems to be encroaching on the territory of Open Street Map (OSM) that uses ONLY public domain (not the same as free) and user-contributed data. But the data users contribute to Google Maps (in the form of reporting problems on the map) become the property of Google and its data providers.

From the OSM Wiki, “The copyright of the whole data set is scattered among all contributors. Some contributors release their contributions to the public domain.” Readers interested in learning more about maps in the public domain should read this Guardian article about the UK’s Ordnance Survey heavy grip on its data.

Disclaimer: I felt prompted to write this post because James Fee on his blog often (1st) writes (2nd) about the (low) quality of the data Google puts in its Maps.

*Users have long been able to report problems, but never in such an easy way or one that tracks reports and notifies the user when Google fixes the error.

GIS and mapping tools

February 9, 2009 / / 0 Comments

Some of the work I do for school and my job requires that I make maps. I’ve never taken a class on how to make maps or analyze data sets featured in maps (what GIS does), so I learn as I go.

There’s no one around me I can call upon when I have questions that need immediate answers. Well, there’s me! Because of this, I must quickly find a solution or workaround myself.

Today I had to import a list of Chicago Transit Authority and Metra rail stations into ArcGIS so I could plot them on a map that also showed Chicago’s boundary and our bikeways. I could do this in Google Earth, but then I would have less control over the printed map I wanted to make, or the image output. ArcGIS has a built-in geocoder and I learned how to use it six months ago, but a skill not practiced is lost – and I forgot how to do it.

That’s okay – what follows is how I overcame this barrier:

Because I know how to use PHP to instantly create Keyhole Markup Language (KML) files (the format which Google Earth and Maps speaks fluently). Then, with this user-contributed KML to SHP plugin for ArcGIS, I was able to convert my KML files to Shapefiles and display them on my map. Unfortunately, my custom “fancy” icons were lost in the translation. Supposedly this alternate user-contributed script does the same thing.

Other tools I used to get my map created:

  • BatchGeocode.com – This site is indispensable for turning a list of addresses (with names, descriptions, and URLs) into the same list but with latitude and longitude coordinates! It will even create a KML file for you.
  • KML Generator (PHP class) – This class allows you to quickly and easily create KML files from any array and array source of coordinates. I store the transit stations in a database and run a query on the database and loop through them to generate the points in a KML file.

I’d like to thank James Fee’s GIS Blog for the links to the ArcGIS scripts/plugins I used in my project. To everyone else who must confront software, technology and mapping roadblocks, there’s almost always a solution for you.

Read about how I got around QGIS’s lack of geocoding.