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Mapping Data: Beyond the Choropleth

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.

oobrien

May 24, 2016
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  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)
    7
    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
    15

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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)
    25
    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
    30
    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
    37
    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
    50

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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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