Posts in category GIScience

October 30th, 2014

This map is a lie

I came across a startling map on Maps Mania today. Back in May 2013 Monica Stephens, and colleagues, published online maps showing twitter data that contained hateful words related to homophobia and racism. The message communicated by the maps is quite strong and shocking – racism and homophobia are extremely strong in the eastern half of the United States. The problem however is that these maps lie and are artifacts of poor cartographic methodology.


September 14th, 2014

Book map

As I finish certain books I have often thought “I wish I had noted the path of the character so I can make a map of it.” I decided to do so for the novel by Jonas Jonasson titled The Hundred-Year-Old Man Who Climbed Out of the Window and Disappeared. It turned out to be a rather good book to do this for as the character circles the globe a few times. The novel in itself is entertaining but lacks depth.

I created the map using QGIS after giving up trying to do something a bit fancier and dynamic with Odyssey.js. It turns out Odyssey.js is a gateway gimmick to attract people to trying CartoDB, the company that created Odyssey.js. To make any really interesting maps with overlays you need to serve your data from CartoDB. They have free accounts but I don’t wish to have my maps dependent on them when, as in this case, it simply isn’t necessary. CartoDB could have easily made it so you can embed your own lines and polygons. Only markers are possible.

Using QGIS unfortunately wasn’t as simple as I desired. I originally wanted to use an azimuthal equidistant map centred on Sweden but QGIS gets very buggy and cuts off portions of the map as well as breaking apart continents. I selected the North Pole instead. This was suitable as it is not so far away from Sweden. I edited the map in Illustrator because QGIS map editing is painful as well. The map I made has absolutely no finesse but I figured I had better post it as it is otherwise I may never get around to making a nicer version and sharing it.

North Pole Azimuthal Equidistant projection

North Pole Azimuthal Equidistant projection

My main lesson to anyone who wishes to do the same is to keep more detailed notes. I tracked the date and location as well as the page number it appeared on but never the mode of travel between data points. My motivation for making a map dwindled as I realized that I really should have noted the mode of transportation.

May 19th, 2014

Countryside map

The University of Namur’s library has some wonderful building, local, regional and national maps on their NEPTUN site. They provide a Google Map like pan and zoom functionality using a commercial Flash program called Zoomify. It’s unfortunate they chose to pay for functionality that’s freely available from OpenLayers or Leaflet. Regardless of this the data is not downloadable as a large file. I do not see why data such as this is not made easily and freely available. As a University it seems that it should be encouraging the sharing of past knowledge. In order to help them, and because a colleague asked me for a map, I have created a script that downloads all the tiles and reorganize them into one image. The script and instructions are on github. It’s obvious why it’s called Poseidon right?

May 18th, 2014

A mess of classified streets

If you ever want to test a potential hire for a GIS position give them a task to accomplish using a different GIS system than that which they are familiar with. Having taught GIS for almost 10 years, it’s clear that those students who are capable simply read the documentation or do a search online for the best way of accomplishing their desired task. So presenting a potential recruit with a new GIS system will quickly reveal whether they are familiar with the concept of figuring things out on their own by searching online. Once you are familiar with the GIS concepts, any GISystem should be straight forward.


June 10th, 2013

Tightly packed paths filling space.

As part of my urban modelling work, now behind me, I was thinking of ways to fill empty spaces with potential residences. These randomly generated parcels would then be evaluated by potential home buying agents. This is rather different as there is no limit to parcel sizes. It’s more of an exploration of patterns generated based on random rules. The paths grow, one at a time, until they hit another path (or themselves). They can only turn 45 degrees.

The beauty is that the paths wrap around the edges of the canvas. This makes it perfect for tiling. Now that we can use SVG natively in HTML you can export your generated pathways and add them to your website background. The application allows you to vary the size of the tile and the path density (cell size).

Give it a try.

December 23rd, 2011

Google map overlayed with graph data

In the spring of 2011 I contacted the city of Luxembourg regarding obtaining data on their city bike share system, named vel’oh!, in order to use the data with the students I taught GIS to in the fall of 2011. Unfortunately no students showed interest in the data. I however dove into the data and did all sorts of spatial analysis and determined trends, statistics and visualizations to better understand the data. I was really only scratched the surface. With over 70 bike stations in the city, each one provides large possibilities for analysis. With my supervisor we met with the data donor from the city and presented our findings. During this meeting he asked me whether I thought certain stations required more bike locks/docks. Typically a station has 15-30 bike docks. The data I had could not address this question but I knew how to find the data in order to answer the question.


December 8th, 2011

Example output from the symbol generator

I have spoken about inappropriately sized symbols in the past before. While generating some of the graphics for those articles I realized that it would be quite easy to generate the symbols automatically based on their values rather than trying to size them manually within the graphics editor. This could prevent myself as well as others inadvertent editing mistakes as well as methodological ones where people simply do not consider the correct representation of symbols.

Check out the resulting Cartographic symbol generator page for more details.

October 13th, 2011

Country Population Distribution header

I have been pondering for some time what the result of displaying bar charts of latitude and longitude population distributions for countries would look like. A co-worker shared a site with city populations for the whole world. I finally managed to get around to creating a mashup of Google Charts and Maps.


June 6th, 2011

Spheres of colour

I’ve spoken before about the great cartographic course I took during my undergrad that referred to the book How to Lie with Maps. Many of the lectures (and examples in the book) contained examples of chart and map errors/propaganda/lies. Since then I have kept an eye out for other examples. I am often rewarded with examples such as this:

Debt chart with graphic error


April 27th, 2011

City Evolution close up

I recently read a journal article my supervisor had co-written and thought “I can do this!”. The article clearly laid out a procedure for creating a model that would distribute houses around a central business district based on the preferences of the agents and other model parameters.