Osgis sept2012  cartogrammar
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  • A map which shows statistical information in diagrammatic form Statistics first , geographical accuracy second
  • Traditional shaded map including info on statistics and Cartogram with regional areas distorted to represent the statistic
  • Similar for GCSE performance in England
  • Create, Share and reuse Production strength service and toolset Break the barriers to current creation by non specialists
  • Using work done on Unlock Text API For scaling - Use of multiple instances on multiple servers in the cloud ScapeToad is a cross-platform, open-source application for producing cartograms. Its written in Java and uses the ESRI Shapefile format for input and output.
  • API is the main guts of it – interfaces with the guts of Scape Toad Allows upload and download of input and output files Website uses a wizard to guide user through creation process
  • Access to gallery to view and download existing Cartograms fir unregistered users Registered users able to create new cartograms and contribute them to gallery


  • 1. OSGIS 2012, Nottingham Sandy Buchanan Project ManagerSlide 1 of ## <<Enter presentation title here>>
  • 2. What is a Cartogram?car·to·gram/ˈ kärtəˌ gram/ A map on which statistical information is shown in diagrammatic form. A small diagram on the face of a map, showing quantitative information. An abstracted and simplified map the base of which is not true to scale.
  • 3. Funded By Developed BY ESRC EDINA
  • 4. Example Traditional Map with Cartogram – Area proportional shading to cases
  • 5. Example Local Authority GCSE performance
  • 6. Project Goals • To enable social scientists and others to create, share and reuse bespoke cartograms • The project will offer a production strength generic service and associated toolset. • It will alleviate the problems associated with production complexity and computational expense.Slide 6 of ## <<Enter presentation title here>>
  • 7. Technology Being Used • Celery and RabbitMQ to manage the distributed task queue including the ability for multiple instances on multiple servers i.e. send it to the cloud if required • Using ScapeToad Cartogram generation. ScapeToad is a cross-platform, open-source application for producing cartograms. Its written in Java and uses the ESRI Shapefile format for input and output. • The algorithm used to compute the cartogram is based on the diffusion-based method for producing density equalizing maps by Michael T. Gastner and M. E. J. Newman
  • 8. Technology Solution
  • 9. Outputs • The main output from the project is an API • The API is then used to service a website allowing non technical users to generate cartograms. • There is also a ‘widget’ allowing users to embed the basic website functionality in their own site. • The API, can of course, be used directly
  • 10. The API • The API is accessed through the use of cURL commands or a REST Console/Client. These are available as add-ons for Chrome and Firefox web browsers. • Documentation and user guide available soon
  • 11. The API• The API • Allow authenticated users to upload a validated, virus checked shapefile. • The shapefile can be ‘simplified’ to reduce computational time. • Select polygon layer to transform and the metric variable linked to that layer that will become the metric layer for the cartogram • Utilise the Gastner/Newman diffusion-based algorithm • Allow the computation to be farmed out to multiple servers if required for complex cartograms • Allow retrieval of new cartogram, shapefiles, distortion grid and metadata
  • 12. The Website • Searchable gallery of user contributed cartograms • Cartogram generation interface • Multiple cartograms from a single shapefile • Output generation • Download • Access to ‘Widget’ Code • Access to API documentation • Further Cartogram resources
  • 13. Website
  • 14. Job Management Screen
  • 15. Shapefile and Metadata
  • 16. Creation Parameters
  • 17. Cartogram View and Download
  • 18. Generate Widget Code
  • 19. Embedded Widget
  • 20. Progress • API is complete • Website is complete and about to be moved onto production (a few workflow tweaks needed) • Widget works • Looking for volunteer testers