How do I find the population within a defined radius of a certain point?

May 21, 2007 7:58 PM

I'm looking for a tool (preferably free) that will provide population data for the area within a defined radius of a point on a map.

Ideally, it would be a website that allows you to click on a map, set a "center," and choose a radius from the center (say 10, 20, 100 miles). It would then provide information on the population within the chosen radius. At a minimum I need information on population size, but other demographic data would be helpful as well.

If there's no such site (or it's expensive), next-best would be a tool that at least provides this information for major metropolitan areas.

posted by brain_drain to Education (11 answers total)

The only source that has data that good is the US Census Bureau, and I'm pretty sure they don't have it online. It's not that it's secret, just that it's immense and the work involved would be titanic -- well beyond their resources.

You can get data to the granularity of "census tracts". I think that's the best you'll find, and that you have to pay for. For free, granularity of counties is about the best you can hope for.

But if what you want is anywhere, it's going to be here.
posted by Steven C. Den Beste at 8:04 PM on May 21, 2007

This is the closest thing I know of that is available for free.
posted by 517 at 9:19 PM on May 21, 2007

You can get the (USA) Census the block and block-group level data for total population online (they need it for redistricting), but I don't think they have the tool you want.

In terms of an easy to use online tool I'm not aware of anything, but if you're committed you can download the Census block-group boundary files (which include centroids for each area) and mess around with those.
posted by thrako at 9:30 PM on May 21, 2007

Try looking in here. One of these was posted to mefi a year or so ago, but I can't find it.
posted by IronLizard at 9:40 PM on May 21, 2007

Also gcensus.
And here's the one I couldn't find, neighboroo.
posted by IronLizard at 9:44 PM on May 21, 2007

BTW, neighboroo seems to be broken.
posted by IronLizard at 9:49 PM on May 21, 2007

ESRI publishes this information on ArcCatalog as a service. The dataset that I'm looking at seems to be from the 2000 census (published 2004) and has information by both zip and city. I'm guessing its only available to people with ArcGIS licenses... the local public university library should have a subscription, at the least. It'd be pretty trivial to write a query in ArcGIS to get the population within a radius from this info.
posted by devilsbrigade at 10:05 PM on May 21, 2007

You aren't going to be able to do the point and click thing without using GIS software and the data is freely available over the Internet from the Census Bureau - the software to do it however isn't. Even so, if you do a query the numbers wouldn't be accurate because it will include folks outside the area that you selected. I'm suspecting that there would be partial zip codes that would get thrown in the mix. The data isn't that granular yet.

If I were you, I would just pick the zip codes you need and plug them into a service like Melissa Data. This is an example of the Dallas area, but you can go as close as the zip code to get even more granularity, and that is as close as you will get really.
posted by bigmusic at 12:19 AM on May 22, 2007

You can't select the radius, but this tool does give you a 1 mile, 3 mile and 5 mile readout.

Address: 200 schermerhorn
City: Brooklyn
State: NY

Variable 1 Miles 3 Miles 5 Miles
Total Population 125,576 924,920 2,402,584
Total Households 55,581 367,812 945,583
Median Income $48,937 $34,571 $37,221
Average Income $75,496 $55,421 $58,905
Median Age 34.30 32.90 32.90
Male Population 60,701 440,740 1,145,613
Female Population 64,875 484,180 1,256,972
White Population 65,063 349,562 1,018,707
Black Population 37,599 328,284 771,590
Am. Indian Population 473 4,067 9,837
Pac. Islander Population 90 595 1,474
Asian Population 5,719 95,585 229,831
Other Population 10,701 106,153 267,043
2+ Race Population 5,931 40,675 104,103
Hispanic Population 24,761 214,083 529,517
posted by cashman at 6:50 AM on May 22, 2007

From the same folks - this gives you a little more control over things, I think. You have to sign up (free).

And then this is pretty much expensive, but it's the 'actual functionality' arm of that same site.
posted by cashman at 11:07 AM on May 22, 2007

Response by poster: This is a great set of options. I'm still working through them, but it looks like I will find something at at least roughly approximates what I need. Thanks everyone!
posted by brain_drain at 12:58 PM on May 25, 2007