Mapping Data: Beyond the Choropleth

Contents: Technology Summary for Web Mapping, Choropleth Maps: The Good and the Bad, Moving Beyond the Choropleth, Example: CDRC Maps, Example: named – KDE “heatmap”, Case example: Country of Birth Map - concerns of the data scientist & digital cartographer.

Transcript

1. Mapping Data:
   Beyond the
   Choropleth
   Oliver O’Brien
   Senior Research Associate
   UCL Dept of Geography
   Twitter: @oobr
   Research blog: http://oobrien.com/
   ADRC-E Training Course: Introduction to Data Visualisation
   16-17 May 2016, Farr Institute, UCL
   

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2. Contents
   •  Technology Summary for Web Mapping
   •  Choropleth Maps: The Good and the Bad
   •  Moving Beyond the Choropleth
   •  Example: CDRC Maps
   •  Example: named – KDE “heatmap”
   •  Case example: Country of Birth Map
   –  Concerns of the data scientist & digital cartographer
   2
   

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3. 1. Technology Summary for Web Mapping
   3
   

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4. Managed Wrappers
   •  MapBox Studio
   •  CartoDB
   •  ESRI ArcGIS Online
   •  Tableau
   •  Google Fusion Tables
   •  Google Maps Embed API
   •  Google Static Maps API
   4
   Example: MapBox Studio style editor
   

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5. JavaScript APIs
   •  OpenLayers
   •  Leaflet
   •  D3
   •  Google Maps JS API
   5
   http://earth.nullschool.net/
   http://osm.org/
   

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6. Programming/Scripting
   –  Typically to produce raster imagery which then can be
   combined with vector data in a Javascript API (or other)
   map
   –  R
   –  Java
   –  Mapnik
   6
   http://twitter.mappinglondon.co.uk/
   

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7. WMS/WFS
   •  “Non-slippy” webmap servers
   –  MapServer (C++)
   –  GeoServer (Java)
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   http://worldnames.publicprofiler.org/
   

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8. 2. Choropleth Maps: The Good and the Bad
   x  Treat unpopulated and
   populated areas
   similarly
   x  Can be hard to see the
   “story” – the interesting
   results
   x  Prone to M.A.U.P.
   8
   ü  Easy to make
   ü  Computationally quick to make
   ü  Retain a geographic familiarity if done carefully
   ü  Good for comparing areas quickly
   http://maps.cdrc.ac.uk/
   

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9. A Basic Choropleth Map
   Map of household income in the US by census tract. Source: Campus Activism blog.
   

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10. 10
    London Mayoral Election 2016 – Result. Source: BBC News. http://www.bbc.co.uk/news/uk-politics-36303157
    A Basic Choropleth Map
    

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11. Adding Geographical Contextual Features
    US Census: ACS Survey results
    

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12. Adding Geographical Contextual Features
    Map of Housing Affordability, 2014. Source: The Guardian.
    

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13. Adding Geographical Contextual Features
    Map of Philadelphia housing prices per square foot using 2014 property assessment data. Source: Campus Activism blog.
    

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14. Adding Geographical Contextual Features
    Change in Socio-Economic Status, 2011-2011. Source: Neal Hudson at Savills
    

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15. 3. Moving Beyond the Choropleth
    •  Adapting Choropleths
    –  Limiting Display to Populated Places
    •  Dot Maps
    •  Cartograms
    •  Grid Maps
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16. Source: http://jamesjgleeson.wordpress.com/
    

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17. Adapted Choropleth
    •  Limiting Data
    Display to
    Populated
    Places
    •  Adding
    Contextual
    Information
    Source: Neal Hudson at Savills
    

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18. Dot Density
    •  Fairer for population
    fluctuations
    –  Although layering of dots
    is crucial
    •  Hard to read data in
    high-density areas
    •  Assumption of random
    distribution across areas
    –  Unless areas are
    restricted to buildings
    Ethnicity across the New York City metropolitan area. 1 dot = 20 people. Source: Eric Fischer.
    

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19. 19
    Map of ethnicity supergroups based on ONS Census (2001) data. 1 dot = 50 people. Source: @geographyjim
    Dot Density
    

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20. EthniCity from London: The Information Capital (James Cheshire, Oliver Uberti) http://theinformationcapital.com/
    Dot Density
    

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21. Single Dot in Area Centroid
    21
    Wards - London’s Political Colour
    http://vis.oobrien.com/london/
    Map: OSM CC-By & OS OGL
    

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22. 22
    http://vis.oobrien.com/tube/#metric=wardwords
    Data: ONS & OS, OGL.
    

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23. Cartograms
    •  Fairer display of data
    •  Harder to relate geography unless carefully done
    Maps from Worldmapper: http://www.worldpopulationatlas.org - © SASI Research Group, University of Sheffield
    

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24. Cartograms
    Created by Ben Hennig – http://viewsoftheworld.net/
    

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25. Square Cartograms
    •  Aftertheflood
    Squares
    (Boroughs)
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    Map/Concept: Aftertheflood.co (L). GLA version (R).
    

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26. Half Way Between Choropleth & Cartogram
    •  Rentonomy (Postcode Prefixes)
    26
    Source: Rentonomy. http://www.rentonomy.com/london-rental-map
    

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27. 27
    Gridded Choropleth
    Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
    

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28. 28
    Gridded Choropleth
    Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
    

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29. 29
    Gridded Choropleth
    Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
    

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30. 4. Example: CDRC Maps
    •  CDRC needs maps of population/consumer data
    which are quick to interpret and effective
    •  The technology is simple
    –  We want to maintain the simplicity of creating
    choropleth mapping
    •  The key innovations are to:
    –  Put some contextual information above the choropleth
    –  Constrain the choropleth display to areas of population
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    http://maps.cdrc.ac.uk/
    

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31. 31
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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32. 32
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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33. 33
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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34. Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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35. Map Layers
    •  Also Postcode Pin Layer (Vector)
    •  KML Drag-and-Drop Display Layer (Vector)
    

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36. Tabular Data > Choropleth > Real-World Map
    

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37. UI Evolution: “New Booth” > DataShine > CDRC Maps
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    Map data: OS & ONS OGL. Sources: http://vis.oobrien.com/booth/ + http://datashine.org.uk/ + http://maps.cdrc.ac.uk/
    

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38. Geodemographics
    & Indices
    on CDRC Maps
    •  OAC, LOAC, TOAC
    •  COWZ-EW, IUC
    •  IMD 2010 & 2015,
    2010-15 Change,
    Components Diff
    •  SIMD 2012
    •  Retail – Rental Value,
    Value Change by
    Sector
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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39. Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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40. Software (for CDRC Maps)
    •  Simple (static image “tiles”) – no “map server”
    •  Apache web server
    •  Mapnik (pre-renders the images)
    –  & python-mapnik (to slice them up)
    •  OpenLayers (3)
    •  JQuery and JQueryUI (for the non-map UI)
    •  PostgreSQL database
    –  PostGIS spatial extensions
    

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41. 5.
    Examples:
    named
    41
    Source: Adapted from named. http://named.publicprofiler.org/
    

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42. Source: named. http://named.publicprofiler.org/
    

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43. Replacing the “Worldnames” Choropleths
    Source: http://worldnames.publicprofiler.org/
    

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44. KDE Mapping: “Sinclair”
    

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45. KDE Mapping
    Graphs: Wikipedia. Background Map: OpenStreetMap.
    

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46. •  “Where your name is
    unusually popular”
    •  “Where we think you might
    have met”
    The Website
    Source: named. http://named.publicprofiler.org/
    

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47. The Response…
    Sources: Daily Mail and Mirror websites.
    

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48. Software (for named)
    •  Java service which retrieves the data, grids it,
    creates a corresponding KDE grid and converts it
    to a PNG
    •  Apache web server
    •  PHP to glue the two together
    •  OpenLayers (3)
    •  JQuery and JQueryUI
    •  PostgreSQL database
    –  No need for a spatial database as just points
    

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49. 6. Case Example: Country of Birth Map
    •  “Top Metric” maps are pseudo-geodemographic
    maps
    –  showing a single value for an area that represents the
    most significant part of the population there
    49
    

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50. 6. Case Example: Country of Birth Map
    •  Need three kinds of skills
    –  Data Scientist
    •  to manage the data and discover the story
    –  Demographic Geographer
    •  to make it a representative map
    –  Digital Cartographer
    •  to communicate the story effectively
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51. •  Top Metric Maps require care and curation to produce a
    map with:
    –  fair groupings – wary of aggregation bias
    –  a sensible threshold – maximise signal-to-noise ratio but don’t
    lose the story
    –  appropriate removal of spatially overwhelming majorities
    –  appropriate colours – use hues to show categorization and
    hierarchies (HSL)
    –  curated emphasis with colours - emphasise/fade certain data to
    tell the story of the data effectively - use brighter hues for more
    unusual results, and more modest ones for results that would
    otherwise dominate, while retaining balance
    Country of Birth Map
    

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52. Country of Birth Map: Data Scientist
    

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53. •  An all-UK map of
    Census 2011 data,
    combining the equivalent
    (but subtly varying) tables
    from the 3 National Statistics
    bodies – ONS, NRS &
    NISRA.
    •  English excluded from all
    UK, & natives from their
    country
    –  Internal national land borders
    included to show these rule
    transitions
    •  8% threshold
    –  Balance between
    “exaggeration” and showing
    an interesting story
    Country of Birth Map: Demographic
    Geographer
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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54. Country of Birth Map: Digital Cartographer
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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55. Country of Birth Map: Digital Cartographer
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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56. Country of Birth Map
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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57. Paper on CDRC Maps Mapping
    •  O’Brien O, Cheshire J (2015)
    Interactive mapping for large, open demographic
    data sets using familiar geographical features
    –  Journal of Maps (T&F)
    –  Published online
    –  Online, PDF download
    –  Open access (CC-By)
    DOI: 10.1080/17445647.2015.1060183
    57
    

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58. Links
    http://maps.cdrc.ac.uk/
    http://maps.cdrc.ac.uk/#/metrics/countryofbirth/
    http://named.publicprofiler.org/
    58
    Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
    

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59. Thanks!
    •  Research blog:
    http://oobrien.com/
    •  Twitter: @oobr
    59
    Source: http://vis.oobrien.com/tube/
    

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