Map of number of Cleveland residents by census tract.
Make sure that ogr2 and TopoJSON are installed properly, see "Let's make a map!" (http://bost.ocks.org/mike/map/) for further instructions
tl_2013_39_tract.shp (via http://catalog.data.gov/dataset/tiger-line-shapefile-2013-state-ohio-current-census-tract-state-based)
cuyahoga-youth2.csv
Take the census tract data for Cuyahoga County, ID 035
ogr2ogr -f GeoJSON -where "COUNTYFP = '035'" input35.json tl_2013_39_tract.shp
Add attributes to the GeoJSON file, mapping the id property from the shapefile (originally) to the column title in the csv file
topojson \
-o outputYouth.json \
-e cuyahoga-youth2.csv \
--id-property=+NAME,+CensusTract \
-p total00=+total00 \
-p total10=+total10 \
-- input35.json Note: delete tract 9900, as it represents the lake itself and does not contain useful information (to the best of my knowledge).