Creating Cartograms in QuantumGIS

Throughout my education, cartograms have been one of my favorite forms of cartographic visualization. Cartograms work on the principle of deforming data based upon an external factor. In the first example, the boroughs of London have been altered based upon the mean equivalent income. As can be seen the City of London region has been significantly increased whereas Havering has been reduced.

Cartogram map of London exaggerated based upon mean income.The above example was created using Quantum GIS and the ‘Cartogram Creator’ plugin. The data used are the London Stat pack provided by the London DataStore and joined to a London boroughs shapefile from the same store. The cartogram projection used in the example is the Dougenik, Chrisman and Niemeyer cartogram. The cartogram is presented alongside a correctly presented map of London to help with comparison. A purple colour ramp due to the associated of the colour purple with wealth.

If you have any comments or suggestions of good cartograms or other maps please post them into the comment box.

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CASA Seminar Series OAC Explorer.

This week, Aidan Slingsby of City university,presented his work on visualization of demographic information,through the OAC explorer. The application uses the OAC census classification scheme to categorize the data and uses a selection of cartograms andcolours to disseminate the maximum amount of information whilst not congesting the viewer. 


Rectangular cartogram of OAC explorer created at City GI centre

 

OAC explorer rectangle cartogram (CityGI centre)
The screenshot above is an example of therectangular cartogtram used to more easily visualize the data. Thoughthere is significant deformation the postcode scheme allows a user to veryeasily navigate through the data down to a specific post code region. One smallissue with this is that the spread out nature of Scotland means ithas been reduced to only the top 2 rows. 

One of the many impressive aspects of the map isthe use of colour. In order to create an equal viewing experience for allcategories the colours have been chosen to have equal hue so there is nodifference in colour lightness. The application has made excellent use of thisby allowing lightness to be applied when a user wishes to highlight particularcategories of interest. 

For more information see:
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Dissertation Web Map

During the final year research project, one of the more successful outcomes of the project was the construction of a web mapping application designed to visualize the suitability of land for shelter camps following rapid onset natural disasters. During this project I communicated with ShelterBoxUK and MapAction to look at where existing services exist and at challenges which may be encountered when working in these environments. The application as demoed in the attached video was constructed using only open source software. The reason being, the platform needed to be available, not just following a disaster but also between events to allow user to gain technical competency, identify and fix faults and finally to increase awareness.
The spatial data was hosted on a virtual server running GeoServer (An open-source map server capable of supporting WFS, WMS, WCS and is beginning to introduce WPS(Web Processing Services)). In order to  access the spatial data stored on the server OpenLayers is used to display the data and apply the styles as specified in the SLD (Style layer descriptor file). The desktop processing element of the project was conducted using quantum GIS. QGIS has the ability to link to WFS servers and can also export the symbology created into the SLD file so the symbology may be replicated across the system.

Though the cartography used within the application is not great it does highlight clearly the areas of the highest suitability vs low as specified in the UN Sphere project minimum standards in disaster management. One of the interested results of the demonstration has been the growing number of views the video has received on YouTube (1314 currently).

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Creating 3D Maps in ArcGIS

As part of the final year visualization module the GIS class were tasked with the construction of a 3D campus map including both a paper visualization and a fly through. This task was split into a number of specific work processes:
1) Topographic data collection of street furniture,
2) Collection of photographic evidence of buildings,
3) Digitization and construction of 3D Buildings,
4) Compilation of all factors,
5) Fly through and paper map production,
Both tasks 1 and 2 where fairly straightforward with photographic evidence of all buildings collected using personal cameras and standard quality GPS devices. Key focus during this exercise was the collection of specific street furniture and safety signage.
Task 3 required the construction of 3D models of all the buildings on the Penryhn road campus. For this purpose ArcGIS has limited functionality and consequently The extruded OS Master Map data was exported using the Collada file from Arc and into Google Sketchup. The 3D construction was fairly general but made key efforts in regards to identifying the recognizable features around the campus. One of the useful quality of ArcGIS is that it allows fully textured and structured 3D models to be imported and substituted for the extruded Master Map building footprints.
As illustrated below the product of this exercise was in my opinion a fairly impressive visualization of the university campus which reasonably well highlighted the locations of faculties and various services through the university site. My personal criticisms of this product where the questionable identification of parking areas and access to buildings.
3D map of Kingston university Penryhn road campus.
Student produced map of Kingston University Penryhn road.
3D map of Kingston university Penryhn road campus created commercially .

                                    Privately produced map of Kingston University Penryhn road

The fly through video was created through the use of ESRI ArcScene and Windows movie maker. ArcScene allows the user to specific views, frames and timing in to move through the scene. Using this function a number of separate sequences around the campus where created and stitched together and annotated using the Windows movie maker application.
Final Video of Kingston University Penryhn road campus
Criticism and feedback of the project:
When comparing the commercially produced map used by the university and the student map created over a period of 3 weeks it is evident that both have strengths and weaknesses but the choice is left open to you. Following the submission of the work it was displayed at the ESRI used conference and received the media mapping award for the fly through. Some of the suggestions for future iterations of the map where to include symbology to highlight accessibility at specific entrances and to identify the locations of stairwells within the building.
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