Visualization of epidemiological information using area cartograms or density equalized maps
Download
1 / 11

Visualization of epidemiological information using area cartograms or density-equalized maps - PowerPoint PPT Presentation


  • 94 Views
  • Uploaded on

Visualization of epidemiological information using area cartograms or density-equalized maps. C.P.D. Birch Centre for Epidemiology & Risk Analysis, Veterinary Laboratories Agency – Weybridge, Surrey, UK. Introduction. Land area is irrelevant to many epidemiological presentations.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Visualization of epidemiological information using area cartograms or density-equalized maps' - idola


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Visualization of epidemiological information using area cartograms or density equalized maps

Visualization of epidemiological information using area cartograms or density-equalized maps

C.P.D. Birch

Centre for Epidemiology & Risk Analysis,

Veterinary Laboratories Agency – Weybridge,

Surrey, UK


Introduction
Introduction cartograms or density-equalized maps

  • Land area is irrelevant to many epidemiological presentations.

  • So why use it to determine the size of mapping units?

  • Area cartograms provide an alternative.

  • Base the size of mapping units on measures that matter.


Us presidential election 2004
US Presidential Election 2004 cartograms or density-equalized maps

Unit = area

This may be how ex-President Bush would like us to see the

2004 US Presidential

Election result.

Unit = voters

This is a better

representation of how

The US population voted.

M. T. Gastner, C. R. Shalizi, and M. E. J. Newman (2004)


Application in epidemiology
Application in epidemiology cartograms or density-equalized maps

  • Area of mapping units = target population.

  • Hence automatic visual weighting based on population distribution.

  • Shading =

    • Case density

    • Sampling distribution

    • or Other relevant factors

  • Dot density = cases


Application 1 salmonella surveillance
Application 1: cartograms or density-equalized mapsSalmonella surveillance

- without cartogram

  • Shading = density of cattle holdings

  • Dot density = cases

  • Dot density = cases


Application 1 salmonella surveillance1
Application 1: cartograms or density-equalized mapsSalmonella surveillance

- using cartogram

  • Area = number of cattle holdings

  • Shading = cattle per holding

  • Dot density = cases

Birch, C.P.D. (2008)


Application 2 scrapie surveillance
Application 2: cartograms or density-equalized mapsScrapie surveillance

5000

  • Area = number of sheep holdings

  • Shading = % holdings sampled

  • Dot density = cases

Birch, C.P.D., Chikukwa, A.C., Hyder, K., Del Rio Vilas, V.J. (2009)


Benefits of area cartograms in epidemiology
Benefits of area cartograms in epidemiology cartograms or density-equalized maps

  • Better presentation of cases vs. denominator population

    • Direct visualization showing whether cases are uniformly or unevenly distributed.

    • Visual impression more accurate.

  • Richer data presentation

    • More data can be presented.

    • More space on the map for areas likely to contain more information.

  • Precise locations obscured (confidentiality)

  • Maps that emphasize features that matter


Cartogram methods and tools are readily available
Cartogram methods and tools are readily available cartograms or density-equalized maps

  • Downloads for ArcGIS

    • ESRI Cartogram and Geoprocessing Tool (Tom Gross, http://arcscripts.esri.com)

    • Cartogram Creator – used here (Eric Wolf, http://arcscripts.esri.com)

  • Method

    • Gastner & Newman (2004) Proc. NAS 101: 7499-7504

  • Website

    • www.worldmapper.org


Other references
Other references cartograms or density-equalized maps

  • Birch, C.P.D., 2008. Methods for spatial visualization by using maps in animal health surveillance. Veterinary Laboratories Agency, Report to Defra pp. 35.

  • Birch, C.P.D., Chikukwa, A.C., Hyder, K., Del Rio Vilas, V.J., 2009. Spatial distribution of the active surveillance of sheep scrapie in Great Britain: an exploratory analysis. BMC Veterinary Research 5, 23.

  • Gastner, M.T., Shalizi, C.R., Newman, M.E.J., 2005. Maps and cartograms of the 2004 US presidential election results. Advances in Complex Systems8, 117-123.


Visualization of epidemiological information using area cartograms or density equalized maps
Visualization of epidemiological information using area cartograms or density-equalized mapsColin Birch

  • To start presentation click arrow at bottom right.