Am trying to query data from http://www.census.gov, using their API I want to get the population of a particular city in the US, by using the city name and the US state code.
Given that I already have the key, what other parameters do I add in the URL below, so that I can get the population.
http://api.census.gov/data/2010/sf1?key=<my key>
any assistance will be greatly appreciated
Judging from your query URI, you wish to access population data from the 2010 Census Summary File. You would add GET paramaters of get and for to your query. Example:
http://api.census.gov/data/2010/sf1?key=b48301d897146e8f8efd9bef3c6eb1fcb864cf&get=P0010001&for=state:06
The population table as given in the get parameter are identified with a "P" and you can use the for parameter to further narrow down your scope. Examples of valid criteria formatted as URIs can be found here...
EDIT: It seems that for a finer grained search such as cities, you're going to need to use the governments cumbersome FIPS (Federal Information Processing Standard) codes (after converting lat/lon regions to their coding system)... I've found this resource that should be helpful, specifically points 5 thru 7, but it seems mega complex...
Another alternative I found is the USA Today census API, it seems that they mirror the data from the census and they do have available endpoints with data granularity at the city level... Check it out here...
no need to use API the data is available in CSV here http://www.census.gov/popest/data/cities/totals/2012/SUB-EST2012.html
来源：https://stackoverflow.com/questions/19783792/how-to-use-http-www-census-gov-api-to-pull-data