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
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
3. 1. Technology Summary for Web Mapping 3
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
5. JavaScript APIs •  OpenLayers •  Leaflet •  D3 •  Google Maps JS API 5 http://earth.nullschool.net/ http://osm.org/
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/
7. WMS/WFS •  “Non-slippy” webmap servers –  MapServer (C++) –  GeoServer (Java) 7 http://worldnames.publicprofiler.org/
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/
9. A Basic Choropleth Map Map of household income in the US by census tract. Source: Campus Activism blog.
10. 10 London Mayoral Election 2016 – Result. Source: BBC News. http://www.bbc.co.uk/news/uk-politics-36303157 A Basic Choropleth Map
11. Adding Geographical Contextual Features US Census: ACS Survey results
12. Adding Geographical Contextual Features Map of Housing Affordability, 2014. Source: The Guardian.
13. Adding Geographical Contextual Features Map of Philadelphia housing prices per square foot using 2014 property assessment data. Source: Campus Activism blog.
14. Adding Geographical Contextual Features Change in Socio-Economic Status, 2011-2011. Source: Neal Hudson at Savills
15. 3. Moving Beyond the Choropleth •  Adapting Choropleths –  Limiting Display to Populated Places •  Dot Maps •  Cartograms •  Grid Maps 15
16. Source: http://jamesjgleeson.wordpress.com/
17. Adapted Choropleth •  Limiting Data Display to Populated Places •  Adding Contextual Information Source: Neal Hudson at Savills
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.
19. 19 Map of ethnicity supergroups based on ONS Census (2001) data. 1 dot = 50 people. Source: @geographyjim Dot Density
20. EthniCity from London: The Information Capital (James Cheshire, Oliver Uberti) http://theinformationcapital.com/ Dot Density
21. Single Dot in Area Centroid 21 Wards - London’s Political Colour http://vis.oobrien.com/london/ Map: OSM CC-By & OS OGL
22. 22 http://vis.oobrien.com/tube/#metric=wardwords Data: ONS & OS, OGL.
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
24. Cartograms Created by Ben Hennig – http://viewsoftheworld.net/
25. Square Cartograms •  Aftertheflood Squares (Boroughs) 25 Map/Concept: Aftertheflood.co (L). GLA version (R).
26. Half Way Between Choropleth & Cartogram •  Rentonomy (Postcode Prefixes) 26 Source: Rentonomy. http://www.rentonomy.com/london-rental-map
27. 27 Gridded Choropleth Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
28. 28 Gridded Choropleth Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
29. 29 Gridded Choropleth Map data: ONS OGL. Source: Duncan Smith, UCL CASA. http://luminocity3d.org/
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/
31. 31 Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
32. 32 Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
33. 33 Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
34. Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
35. Map Layers •  Also Postcode Pin Layer (Vector) •  KML Drag-and-Drop Display Layer (Vector)
36. Tabular Data > Choropleth > Real-World Map
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/
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/
39. Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
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
41. 5. Examples: named 41 Source: Adapted from named. http://named.publicprofiler.org/
42. Source: named. http://named.publicprofiler.org/
43. Replacing the “Worldnames” Choropleths Source: http://worldnames.publicprofiler.org/
44. KDE Mapping: “Sinclair”
45. KDE Mapping Graphs: Wikipedia. Background Map: OpenStreetMap.
46. •  “Where your name is unusually popular” •  “Where we think you might have met” The Website Source: named. http://named.publicprofiler.org/
47. The Response… Sources: Daily Mail and Mirror websites.
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
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
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
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
52. Country of Birth Map: Data Scientist
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/
54. Country of Birth Map: Digital Cartographer Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
55. Country of Birth Map: Digital Cartographer Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
56. Country of Birth Map Map data: Ordnance Survey and ONS OGL. Source: http://maps.cdrc.ac.uk/
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
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/
59. Thanks! •  Research blog: http://oobrien.com/ •  Twitter: @oobr 59 Source: http://vis.oobrien.com/tube/