Census Geography: Maps

& AppsJoe Germuska

NewsApps DeveloperChicago Tribune

0:00

Census Geographies

http://www.census.gov/geo/www/geodiagram.pdf

1:30

SUMLEV

3:03

Key Summary Levels

• Block (~ 8M): basis for all tabulated data

• Block Group (~211K): smallest geography for which sample data is published

• Tract (~74K): relatively permanent; 1200-8000 people (optimum: 4000)

• County (3,143)

• State (52)

• Division (9)

• Region (4)

• Nation (1) (and then there are the “Island Areas”)

4:57

Other Groupings

•Place (7,438): Incorporated and Census Designated (CDP)

•County Subdivision (36,642)

•Core Based Statistical Areas (942)

7:20

Geographic Components

•about 100 different geographic components, with most focusing on urban/rural or metropolitan/non-metropolitan distinctions

•Nation

•Region

•Division

•State

•CBSA

9:00

TIGER Shapefiles

9:46

Shapefiles

•In addition to tabulation geographies:

•Roads

•Hydrography

•Landmarks

•Military Installations

10:40

Gazetteer• Delimited text files provide IDs, names, area, centroid for:

• 111th Congressional Districts

• Census Tracts

• Counties

• County Subdivisions

• School Districts - Elementary, Secondary, Unified

• State Legislative Districts - Lower & Upper

• Places

• ZIP Code Tabulation Areas

• GeoID not always exact match for shapefile (prefix, etc)

11:10

Keep in Mind

• Geos can change between “vintages”: compare with caution. Consult “crosswalk”

• Know which geos are contained by larger geos and which can “overlap”

• Choose your summary level carefully

• 080 “Census Tract” ≠ 140 “Census Tract”

• Exercise extreme caution when aggregating to non-census geographies

11:50

Population Change Map

14:54

WNYC Map

15:28

Know Spokane

15:35

Options

Chicago Tribune

WNYCSpokesman-

Review

Tile MillGoogle Fusion

TablesGeoDjango + Google Maps

15:44

Tile Mill

16:17

Tile Mill

•Can be entirely hosted on any simple web server (Amazon S3)

•Tile generation can be slow, especially for close zoom levels

•Evolving rapidly, especially interactivity

18:14

Fusion Tables

19:33

Fusion Tables

•Can import KML for shapes, sometimes data

•More often, KML for shapes, then join with data

•Easy to embed

20:10

GeoDjango

21:02

GeoDjango

•Highly customizable

•Well-documented, healthy user community

•Hosting adds extra layer of complexity

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22:32

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24:00

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census.ire.org

•Browse and compare

•Correctly computed changes since 2010

•Export as CSV, JSON, KML

•JSON available for web apps

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Example JSON datahttp://…/15/1571550.jsonp*

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You can join the fun

• CENSUS-L » http://www.ire.org/join/listserv.html

• https://github.com/ireapps/census

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Questions?

•Links for this presentation:

•http://j.mp/muCTyM

•http://blog.apps.chicagotribune.com

•Twitter:

•@JoeGermuska

•@TribApps

32:07

Links• Census Geographic Resources

•http://www.census.gov/geo/www/tiger/tgrshp2010/tgrshp2010.html

•http://www.census.gov/geo/www/2010census/gtc_10.html

•http://www.census.gov/geo/www/2010census/GTC_10.pdf

• Example Apps

•http://media.apps.chicagotribune.com/census-2010/population-change/index.html

•http://data.spokesman.com/census/2010/washington/

•http://project.wnyc.org/census-maps/2010pop.html

• How-tos:

•http://blog.apps.chicagotribune.com/2010/02/17/quick-install-pythonpostgis-geo-stack-on-snow-leopard/

•http://blog.apps.chicagotribune.com/2011/03/08/making-maps-1/

•http://blog.apps.chicagotribune.com/2010/02/17/hello-newsroom-a-simple-geodjango-application/

• http://www.ire.org/census/

• https://github.com/ireapps/census

• http://www.ire.org/join/listserv.html32:17