Gothos

I recently received my first question from someone who wanted to compare 2005-2007 ACS data with 2008-2010. With the release of the latter, we can make historical comparisons with the three year data for the first time since we have estimates that don’t overlap. We should be able to make some interesting comparisons, since the first set covers the real estate boom years (remember those?) and the second covers the Great Recession. One resource that makes such comparisons relatively painless is over at the Missouri Census Data Center. They’ve put together a really clean and simple interface called the ACS Trends Menu, which allows you to select either two one period estimates or two three period estimates and compare them for several different census geographies – states, counties, MCDs, places, metros, Congressional Districts, PUMAs, and a few others – for the entire US (not just Missouri). The end result is a profile that groups data into the Economic, Demographic, Social, and Housing categories that the Census uses for its Demographic Profile tables. The calculations for change and percent change for the estimates and margins of error are done for you.

Downloading the data is not as straightforward – the links to extract it just brought me some error messages, so it’s still a work in progress. Until then, a simple copy and paste into your spreadsheet of choice will work fine.

If you like the interface, they’ve created separate ones for downloading profiles from any of the ACS periods or from the 2010 Census. The difference here is that you’re looking at one time frame; not across time periods. The interface and the output are the same, but in these menus you can compare four different geographies at once in one profile. Unlike the Trends reports, both the ACS and 2010 Census profiles have easy, clear cut ways to download the profiles as a PDF or a spreadsheet. If you’re happy with data in a profile format and want an interface that’s a little less confusing to navigate than the American Factfinder, these are all great alternatives (and if you’re building web applications these profiles are MUCH easier to work with – you can easily build permanent links or generate them on the fly).

The US Census Bureau also recently put together a great resource called the Guide to State and Local Census Geography. They provide a census geography overview of each state: 2010 population, land area, bordering states, year of entry into the union, population centroids, and a description of how local government is organized in the state – (i.e. do they have municipal civil divisions or only incorporated cities and unincorporated land, etc). You get counts for every type of geography – how many counties, tracts, ZCTAs, and so on, AND best of all you can download all of this data directly in tab delimited files. Need a list of every county subdivision in a state, with codes, land area, and coordinates? No problem – it’s all there.

I’ve had a few interesting projects that have kept me busy at the end of this year. I’ll do a post or two after New Years, once I’m back in the office and can take some screen shots to illustrate.

In the meantime I have one tidbit I can mention – the Census Bureau has released the 2010 version of the Generalized Cartographic Boundary Files. These files are generalized versions of the TIGER files, with smoothed and simplified boundaries and areas of coastal water removed. They haven’t posted them on the same page as the 2000 and 1990 boundaries; they’ve mentioned they’re creating a new interface to host all of them, which is currently a work in process at http://www.census.gov/geo/www/cob/.

However, you can get access to all the 2010 boundaries via the FTP site – you just need to know what you’re looking at. All the files are named with codes to identify the geographic coverage, summary level, and resolution / scale. There’s a README file on the FTP page that tells you how to identify each.

But in brief – The file names look like this: gz_2010_ss_lll_vv_rr.zip, where:

• ss is the state INCITS / FIPS code which you can look up here – ‘us’ is a national level file.
• lll is the summary level or unit of geography – the README file has a table with each code. The most common ones: 040 for state, 050 for county, 060 for county subdivisions, 140 for census tracts, 160 for places, 310 for metropolitan and micropolitan statistical areas, 860 for ZCTAs. (No PUMAs- 2010 PUMA boundaries haven’t been drawn yet, and 2000 PUMA boundaries are still being used in the latest ACS).
• vv is a version number for the file.
• rr is resolution – most of the files are 500k = 1:500,000, which is the least generalized and best for mapping state-level to regional areas. For national level files you also have the option of 5m = 1:5,000,000 and 20m = 1:20,000,000, which are more generalized and better for national mapping.

The Census Bureau has been doing a lot of tweaking to their website lately. The legacy version of the American Factfinder is set to disappear for good on Jan 20, 2012.

With the release of both the 2010 Census profiles for ZCTAs (ZIP Code Tabulation Areas) and the TIGER line files for 2010 Census geographies, I created another Google Map finding aid for NYC neighborhood data by ZIP code (I previously created one for PUMAs with American Community Survey data). Once again I used the Export to KML plugin that was created for ArcGIS. This allowed me to use the TIGER shapefile in ArcGIS to create the map I wanted and then export it as a KML, while using fields in the attribute table of each feature to insert the ZCTA number into stable links for the census profiles, automatically generating unique urls for each feature. Click on the ZCTA in the map, and then click on a link to open a profile directly from the new American Factfinder.

There were two new obstacles I had to contend with this time. The first was that my department has finally migrated to Windows 7 from Windows XP, and I upgraded from ArcGIS 9.3 to 10. I had to reinstall the Export to KML plugin (version 2.5.5) and ran into trouble; fortunately all the work-arounds were included in the plugin’s documentation. I don’t have administrator rights on my machine, so I had to have someone install the plugin as an administrator; this included running the initial setup file AND running Arc as an administrator as you add and turn the plugin on. That was straightforward, but when I ran it the first time I got an error message – there’s a particular Windows dll or ocx file that the plugin needs and it was missing (presumably something that was included in XP but not in 7). I downloaded the necessary file, and with administrator rights moved it into the system32 folder and registered the file via the command line. After that I was good to go.

The second issue was with the Census Bureau’s new American Factfinder. With the old Factfinder the urls that were generated as you built and accessed tables were static and you could simply save and bookmark them. Not the case in the new Factfinder; you can bookmark some basic tables but most of them are “too complex to bookmark”; you can save and download queries from the online ap but that’s it. After some digging I found a CB document that tells you how you can create deep links to any query you run and table you create. The url consists of a fixed series of codes that identify the dataset, year, table, and geography. So this link:

http://factfinder2.census.gov/bkmk/table/1.0/en/DEC/10_DP/DPDP1/8600000US10010

Tells us that were getting a table from version 1.0 of the American Factfinder in English. It’s from the Decennial Census, 2010 Demographic Profiles, Demographic Profile Table 1, for ZCTA 10010 (860 is the summary level code that indicates we’re looking at ZCTAs). So for the plugin to create the links, I just included this URL but for the last five digits I specified the attribute from the ZCTA shapefile that held the ZCTA code. So when the plugin creates the KML, each KML feature has a link generated that is specific to it:

http://factfinder2.census.gov/bkmk/table/1.0/en/DEC/10_DP/DPDP1/8600000US[ZCTA5CE10]

You can see this previous post for details on how the Export to KML plugin works.

For now, the 2010 and 2000 Census are in the new American Factfinder. The American Community Survey, the Economic Census, population estimates, and a few other datasets are still in the older, legacy Factfinder. According to the CB all of this data will be migrated to the new Factfinder by the end of 2011 and the legacy version will disappear. At that point I’ll have to update my PUMA map so that it points to the profiles in the new Factfinder.

You can take a look at the ZCTA map and profiles below (I’m hosting it on the NYC data resource guide I’ve created for my college). As I’ve written before, ZCTAs are odd Census geographies since they are approximations of residential USPS ZIP Codes created by aggregating census blocks based on addresses; you can see in many instances where boundaries have a blocky teeth-like appearance instead of straight lines. Since they’re created directly by aggregating blocks, ZCTAs don’t correspond or mesh with other census boundaries like tracts or PUMAs, or even legal boundaries like counties. In some cases my assignment of county-based colors doesn’t ring true. For example, ZCTA 11370 includes part of the East Elmhurst neighborhood in Queens and Rikers Island, which is in the Bronx. ZCTA 10463 includes the Bronx neighborhoods of Kingsbridge and Spuyten Duyvil and the Manhattan neighborhood of Marble Hill (a geographic anomaly; it’s not on the Island of Manhattan but it’s part of Manhattan borough).

The most salient issue with ZCTAs is that they are only tabulated for the decennial census and not the American Community Survey; the currency of data and spectrum of census variables will be limited compared to other types of geography.

View Larger Map

The US Census Bureau has begin releasing data for Summary File 1, which is the primary summary data set that the Bureau tabulates. They will release data for groups of states on a weekly basis from June through September. Alabama and Hawaii were the first states released today. California, Delaware, Kansas, Pennsylvania and Wyoming are out next week.

This data is based on the 100% count of the population and is being released for geographies that nest within states: states, counties, county subdivisions, places, census tracts, ZCTAs, and congressional districts, and in some cases block groups and blocks. You can download the data table by table by building queries via the new American Factfinder, or power users can download entire datasets via the FTP site.

You’ll see how small the 2010 Census is compared to the past: we’re only going to get basic demographic variables. The extensive number of socio-economic indicators – education, income, language, employment status, etc – are no longer collected as part of the decennial census; you have to turn to the American Community Survey for this data, which is released on an annual basis.

Here’s what’s in the 2010 Census:

• Total Population
• Urban and Rural Population
• Gender and Age
• Race
• Hispanic or Latino Origin
• Households (Including Type and Size)
• Group Quarters
• Families
• Family Relationships
• Housing Units
• Occupancy Status (Occupied or Vacant)
• Tenure (Owner or Renter Occupied)

Many of these variables are cross-tabulated by age, gender, race, Hispanic or Latino Origin, Household Type, and Household Size. Once we get to the fall of 2011 we’ll start to see national level data for divsions, regions, and metropolitan areas.

The Redistricting Summary Data [P.L. 94-171] from the 2010 Census has all been published for the nation, states, counties, and places, and is available via the new American Factfinder. The redistricting data includes basic demographic data: total population, race, Hispanic or Latino origin, and number of housing units occupied and vacant. Data is available down to census blocks and is available for most (but not all – no ZCTAs or PUMAs) geographies.

If you don’t want all the data for a state, don’t want to slog through the Factfinder, and are comfortable working with large text files, you can FTP the summary data from the Redistricting Data homepage. If you want basic summary data for states, counties, and places and don’t want to fuss with the Factfinder or text files, you can download Excel spreadsheets from the Redistricting Data Press Kit. They also have some pdf / jpg maps showing county level population and population change, plus interactive map widgets like the one below for the country and for each state. 2010 Redistricting TIGER Shapefiles have also been released for geographies included in the redistricting dataset.

The full 2010 Census for all geographies will be released throughout this summer and into the fall in Summary File 1 [SF1]. Stay tuned.

Some geography updates to pass along regarding new US Census data:

• The Census has released a few 2010 map widgets that you can embed in web pages. One shows population change, density, and apportionment for the whole country at the state level, while the other shows population, race, and Hispanic change for states at the county level. As of this post only four states are ready (LA, MS, NJ, and VA) but they’ll be adding the rest once they’re available.
• The 2010 TIGER Line Files are starting to be released; they’ve changed the download interface a little bit based on user feedback. Most summary levels / geographic areas are available; some (like ZIP Codes and PUMAs) will be released later this year.
• They’re also rolling out the new interface for the American Factfinder; currently you can get 2000 Census data, some population estimates, and the 2010 Census data as it becomes available. Other datasets like the American Community Survey and Economic Census will be added over time. Some maps and gov docs librarians have expressed concerned about the change – apparently when you download the data from the new interface the FIPS codes are not “ready to go” for joining to shapefiles; there’s one long geo id that has to be parsed. The other concern is that the 1990 Census won’t be carried over into the new interface at all. The original American Factfinder is slated to come down towards the end of this year.

The 2010 Census is in full swing – the target date of April 1st is coming up soon. I mailed my form back last week. If you’re curious as to how many others have mailed theirs back, check out the bureau’s interactive Take 10 Map. Built on top of a Google Map interface, it allows you to track participation rates by state, county, place, reservation, and census tract. You can zoom in to change the scale and select different geography, or enter a zip code, city, or state to zoom to an area of choice. Clicking on an area will display it’s participation rate to date, compared to the state and national rates.

Data is updated daily, Monday through Friday. Once you click on a particular area, if you click the Track Participation Rate link it will create a widget that you can embed in a website to provide the updated rate. Unlike a lot of the other interactive web maps floating around these days, the bureau does give you the ability to download the actual data behind the map, if you want to do some analysis of your own.