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Osgis sept2012 cartogrammar


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Osgis sept2012 cartogrammar

  1. 1. OSGIS 2012, Nottingham Sandy Buchanan Project ManagerSlide 1 of ## <<Enter presentation title here>>
  2. 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. 3. Funded By Developed BY ESRC EDINA
  4. 4. Example Traditional Map with Cartogram – Area proportional shading to cases
  5. 5. Example Local Authority GCSE performance
  6. 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. 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. 8. Technology Solution
  9. 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. 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. 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. 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. 13. Website
  14. 14. Job Management Screen
  15. 15. Shapefile and Metadata
  16. 16. Creation Parameters
  17. 17. Cartogram View and Download
  18. 18. Generate Widget Code
  19. 19. Embedded Widget
  20. 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