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Census Geography: Maps & Apps. Joe Germuska NewsApps Developer Chicago 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
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Census Geography: Maps & Apps • Joe Germuska • NewsApps Developer • Chicago 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 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 21:37
census.ire.org • Browse and compare • Correctly computed changes since 2010 • Export as CSV, JSON, KML • JSON available for web apps 26:30
You can join the fun • CENSUS-L » http://www.ire.org/join/listserv.html • https://github.com/ireapps/census 29:17
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.html 32:17