How the Census Bureau classifies political and statistical geographic entities

Here's the link to the video recording of a lecture that Michael Ratcliffe, Census Bureau, gave two years ago in a distance learning class organized by Cornell. The topic concerns how the Census Bureau classifies political and statistical geographic entities.

The first 1 hour and 25 minutes are Michael's presentation, and the remainder is second half of the class in which Lars Vilhuber, Cornell, deals with citations in scholarly work—especially citing data. If metadata is your thing you may want to view that lecture as well.

The Growing Blue-State Diaspora

From the New York Times

Californians have moved to Colorado and Nevada. Massachusetts natives have moved to New Hampshire. New Yorkers have moved to North Carolina and Virginia — and, of course, have continued moving to Florida.

Over the last few decades, residents of many traditionally liberal states have moved to states that were once more conservative. And this pattern has played an important role in helping the Democratic Party win the last two presidential elections and four of the last six. The growth of the Latino population and the social liberalism of the millennial generation may receive more attention, but the growing diaspora of blue-state America matters as well.

The blue diaspora has helped offset the fact that many of the nation’s fastest-growing states are traditionally Republican. You can think of it as a kind of race

Place data by county on the Census web page

From a self-described Census geek:

Places within County (or Town)

The Census Bureau uses a three digit Summary Level as a way to identify a certain level of geography. A few Summary Levels to remember are:
040 – State
050 – County
060 – Subcounty (City/Town in NY)
070 – Place/Reminder (or part)

These summary levels are very hierarchical and make up the higher level. So all counties make a state, all subcounties make a county, and all level 070 make up a subcounty. If a place is split by two towns, this place will have two records at level 070, one for each town. The city of Geneva is the only city with two 060 records (one in Ontario and one in Seneca County).

There are some additional summary levels related to places tabulated in AFF and things get very complicated:
155 – County (or part) with Place
159 – Place (or part) with County
160 – Place with State
To see summary levels in AFF you have to go to the Name tab, collapse the Geographic Type in the Filter Options and expand the Summary Level. Level 155 and 159 are normally hidden from view, but shown when you select All Summary Levels in the grey bar above the results.

If you select level 155 you can narrow your results and select Within State and Within County. You end up with a list of places and part of places that are within each County. If a place crosses county boundaries this summary level will give you the results for the part!

Summary level 159 works similar, but instead of a list of counties to select from, you get a list of places and counties to select from. This is not very handy and results are identical to level 155.
Level 160 is a collection of records for places as places do not cross State boundaries. This level is very much equivalent to selecting “City or Town” from the Geographic Type and the places returned using the method Dale described as per Bob’s suggestion returns places with this Summary Level.

So if you want data on the complete places (villages, CDP’s and Cities) that are fully or partially within a county, use level 160. If you are interested in the parts that are within a county use level 155 and if you want to split the places by towns, use level 070.

The Estimates Universe is comparable, but slightly different as it does not contains CDP’s (CDP = Census Designated Places). The Census Bureau assigned a different set of summary levels to this universe. Instead of level 160, 155 and 070, places can be found using Summary levels 162, 157 and 071. That is if the sub county estimates were available using AFF. At the moment these estimates are only available in downloadable format.

HUD USPS ZIP Code Crosswalk Files

One of the many challenges that social science researchers and practitioners face is the difficulty of relating United States Postal Service (USPS) ZIP codes to Census Bureau geographies. There are valuable data available only at the ZIP code level that, when combined with demographic data tabulated at various Census geography levels, could open up new avenues of exploration.

While some acceptable methods of combining ZIP codes and Census geography exist, they have limitations. To provide additional avenues for merging these data, PD&R has released the HUD-USPS Crosswalk Files. These unique files are derived from data in the quarterly USPS Vacancy Data. They originate directly from the USPS; are updated quarterly, making them highly responsive to changes in ZIP code configurations; and reflect the locations of both business and residential addresses. The latter feature is of particular interest to housing researchers because many of the phenomena that they study are based on housing unit or address. By using an allocation method based on residential addresses rather than by area or by population, analysts can take into account not only the spatial distribution of population, but also the spatial distribution of residences. This enables a slightly more nuanced approach to allocating data between disparate geographies.

More HERE.

The new geography of poverty: the suburbs

From Salon.com:


A new report released on Monday by the Metropolitan Policy Program of the Brookings Institution found that poverty is down in urban areas like New York City but is on the rise in surrounding suburbs and has been for the last decade.

According to the analysis of census data, urban poverty in the New York metropolitan area is down by 7 percent, but the number of people living below the federal poverty line in nearby suburbs rose by 14 percent over the past 10 years. As reported by the New York Times:

While New York and Newark’s combined share of poor people in the region dipped from 71 percent to 67 percent, the cities were home to twice the 800,000 or so people who officially qualified as poor in the suburbs in 2010.

Census Bureau Geography website redesigned & reorganized

The Geography section of the U.S. Census Bureau's website has been updated and reorganized to help you better find geography information from the Census Bureau.


The initial phase of the website update includes reorganizing information on the site into seven categories:
About Us
Maps & Data
Reference
Partnerships
Education
Research
GSS Initiative

Many links on the website are changing. In the initial release, the new webpages and the existing webpages are running simultaneously. Not all webpages have been moved to the new design/organization at this time. Some of the older information will be archived. Over the next several months Census will continue to move pages into the updated organization and put in additional redirects to automatically take you from the old pages to the new ones.

If you have any questions about the website please contact geo.geography@census.gov.

The New NHGIS

The Minnesota Population Center is pleased to announce the release of the new National Historical Geographic Information System (NHGIS) website, including:
A redesigned front page providing access to new FAQs, user guides and data documentation
A redesigned data extract system that allows users to:
download multiple years of data in one extract
download multiple geographic levels (states, counties, etc.) in one extract
constrain or expand data searches flexibly by specifying any combination of geographic levels, years, topics, or datasets
The new site also provides Census 2010 Redistricting Data with corresponding 2010 shapefiles. More new data from the American Community Survey and 2010 Summary File 1 will be added throughout the year.
Explore the new site now!
Please note: the original NHGIS website remains accessible, but will be taken offline later this fall, after which users will no longer be able to access previously requested extracts. If you still need to download some requested data or would like to revise or resubmit older extracts through the original site, please do so in the near future.

2010 Guide to State and Local Census Geography

The 2010 Guide to State and Local Census Geography is now available. This Product is an update of the book by the same name that the Census Bureau produced in collaboration with the Association of Public Data Users (APDU) following the 1990 Census. (There was no similar product for 2000.) The 2010 web version offers similar content as the 1990 print version, but also provides links to lists of geographic entities within each state.

This guide provides a nice summary of each state’s geographic structure and some highlights about the state’s geographic history and current geography. Here's New York’s information.

Geographic Products Branch Information

The 2010 Census Geographic Products page is a resource for geographic and cartographic products related to the release of the 2010 Census.

In the past week, Census has released:
Updated Geographic Change Notes – Census 2000 – January 1, 2010
Geographic Comparability File –Places
TIGER/Line Shapefiles – national update including Metropolitan and Micropolitan Statistical Areas and other related Statistical Areas, Military Installations, Tribal Census Tracts, and Tribal Block Groups
2010 Census to Census/2000 Census Tract Relationship File –
Centers of Population

Other selected geographic products currently available:

Reference:
Geographic Terms and Concepts
Tallies of Geographic Entities by state
Block Assignment Files
Name Look-up Tables
Gazetteer Files for Counties, County Subdivisions, Places, Tracts, Congressional Districts, School Districts, and State Legislative Districts

Maps:
Census Tract Reference Maps
County Block Maps
Voting District/State Legislative District Reference Maps
School District Reference Maps
2010 Census Total Population & Population Change Maps

On the 2010 Census Geographic Products page you will also find other reference resources, relationship files, and maps to support the 2010 Census. We are continuing to add products as they become available. If you have any questions about these products please contact geo.geography@census.gov or (301) 763-1128.

Analysis of County Boundary Differences Between 2000 and 2010 Census Geographies

by Joe Francis, Cornell Program on Applied Demographics

Background

Without doubt, data from the 2010 Decennial Census will show changes in the size, composition and distribution of the population in New York State compared to those same indicators from the 2000 Census. These changes will occur at all levels—county, towns, cities and places, tracts, block groups and blocks. In addition to changes in counts of population and housing units, as well as age, sex and racial groupings, there will be changes to the geographies associated with those levels.


While it is common practice to examine the population and housing changes amongst the administrative units under our respective purviews, we are less familiar with examining the changes in the spatial extent and composition of those same administrative units and component geographies (i.e. tracts, block groups, blocks). Consequently, census geographies have been of less concern. Yet we all know that changes in counts may be a function of both population dynamics and changes in redrawn boundaries that enlarge, shrink or reshape the county, town, city, and so forth. Failure to consider that geographies have changed means that when we compare population and housing changes across time, we are assuming that the spatial units have remained constant. Frequently this is an erroneous assumption which can lead to bad analysis and interpretation.

Purpose of Analysis

The purpose of this analysis of boundary differences is to examine the extent to which the changes we observe when comparing data from the 2000 Decennial Census to the 2010 Decennial could be a function of changes in geographies as well as a function of natural increase/decrease and net migration. By examining these boundary changes we establish a firmer basis for asserting that the changes (1) are due entirely to the demographic forces of natural increase/decrease and net migration or (2) are partly due entirely to boundary changes as well, or (3) are due to both.

There are two main reasons for raising the importance of boundary changes at this time. One is that these changes affect not only the Decennial Census but the American Community Survey data products as well. The second reason is that recent advances in GIS technology easily permit such an examination and thereby remove the anxiety of not knowing whether the assumption of common geographies from time one to time two to time three are constant.


True enough that boundary changes only immediately impact comparisons between decennial censuses, but in the not too distant future, that same issue will arise for the American Community Survey (ACS) data as well. As you know, the already reported ACS data are mainly based on 2000 census geography but within two years we face the additional complication of the ACS being tagged to the 2010 census geography (i.e. changes in geographies). Even now some ACS data are based on the 2010 geographies while other ACS data are not. (For additional details, see this Census page.)

Procedure

To increase our understanding of the size and structure of these boundary changes between 2000 and 2010 Census geography, the Cornell Program on Applied Demographics decided to examine the changes starting with changes in county boundaries. With the hope that this investigation will prove of some use to the Affiliates, we share our findings. This report is restricted to county boundary changes. A later report will be about sub-county boundary changes. All analyses were conducted using ArcGIS 10. Details of procedures used can be provided to interested users by writing to Joe Francis (jdf2@cornell.edu) .

Overall Results

Because county boundaries in New York have been relatively stable for over 70 years, we decided to begin the examination here, expecting few changes and a belief that this would be a good testing ground for working out a boundary examination and reporting procedure. To our surprise, there were 79 boundary changes detected in total at the county level. Not all 62 counties had a boundary change but several had more than one boundary difference involved. Montgomery County had the most with 11 differences. Fulton was next with 9. Orleans and Otsego each had 6. Sullivan had 5. Orange, Wyoming and Yates each had 4. Delaware and Schenectady both had 3. Albany, Chautauqua, Schuyler and Tompkins had 2. On the other hand, Allegany, Cattaraugus, Columbia, Hamilton, Herkimer, Oneida, Saratoga, Schoharie, Seneca and St. Lawrence each had 1 boundary change. Three of the observed changes involved counties along the Pennsylvania state line.


Upon examining these 2000-2010 discrepancies about half of them were long narrow slivers involving no housing units and were boundary adjustments we felt weren’t worth reporting. (If there is interest in these, we are happy to provide the details.) For this report, a decision was made to restrict our mapping and reporting to those differences involving at least an acre (4069 sq. meters) or more of land mass. This reduced the number to 42. Counties with 5 boundary differences of an acre or more included Fulton, Montgomery and Otsego. Delaware and Sullivan had 3, while Albany, Orleans and Wyoming had 2. Allegany, Cattaraugus, Hamilton, Herkimer, Oneida, Orange, Saratoga, Schenectady, Schoharie, St. Lawrence, Tioga, Washington, Wayne, and Yates had one each. Of course every boundary involves at least two counties, so more counties were involved than the above list indicates.


Not all of the 42 mapped boundary differences contain significant number of housing units (and therefore people), but a quick look at the jpeg files POSTED HERE will enable you to see what these boundary changes look like. Then you can decide whether or not the change is worth taking a closer look. Like any choice of a threshold cut-point, the choice of one acre or more was arbitrary but based on the idea that land area of that size could accommodate a significant housing worth looking into. In retrospect, we should have moved the threshold higher for the county boundary examination.

Next Steps

Because we are trying to document discrepancies that are of concern to you and report them to the Census Bureau, please let us know your concerns.


For our part at the Program on Applied Demographics, we plan to begin analysis of sub-county geographies next. We expect to see more and more significant changes at that level. Compared to counties, MCD are the next most stable administrative units. If analysis of MCS all works out, we will then move to tracts which involve more fluid dynamics.

UB Libraries Develops New York State Geographic Data/Maps Database

Ever wonder how many more canals there are in New York State other than the Erie Canal? Where are our reservoirs? What areas are designated "forests"? Where are the "falls" other than Niagara? (there are 163 more)

The University at Buffalo Libraries now provides a database, the NYS Gazetteer and GeoData Collection, developed by Geosciences Librarian Michele Shular, which facilitates searching and locating 38,000 places, features, and other geographic information within New York State. Ms. Shular has electronically linked U.S. Geological Survey (USGS) digital maps archived at the UB Libraries with the New York State portion of the "Geographic Names Information System" (GNIS), a Federal repository of official domestic geographic names maintained by the USGS. The NYS Gazetteer and GeoData Collection is available free to the public on the UB Libraries web site. This comes out just in time for Geography Awareness Week, the third week in November.


The digital maps, technically referred to as georeferenced Digital Raster Graphics (DRGs), can be printed for class or field work or imported into Geographic Information System (GIS) applications. For example, DRG topographic maps can be combined with other geospatial data, such as Digital Elevation Models (DEMs), to enhance terrain and slope visualizations useful for site planning, land management, and earth science studies. This GIS import feature is useful for students, technical researchers and professionals in many fields, such as business, government, planning, and more.

Searches can be run on geographic names, feature type, by county map, by U.S. Geological Survey quadrangle, or by a merger of multiple categories. When searching the database, there are links provided to the appropriate feature in Google Maps. For example, you can locate:
4961 schools
298 hospitals
590 towers (largely radio/TV)
427 swamps
68 streams in Erie County
127 islands in St. Lawrence County
This type of extensive geodata/maps/gazetteer database follows the lead of a similar product by University of Virginia librarians.

Ms. Shular notes that the creation of this database is meant to promote and facilitate public access to free topographic maps and gazetteer information for New York State through an easy, searchable interface. "Topographic maps are wonderful tools that provide detailed information for natural and cultural features on the ground, such as slopes, valleys, rivers, roads, and even vegetation cover. Whether it is a K-12 teacher looking for geography class maps, a hiker looking to print a field map, or a GIS technician searching for a digital image to import into a GIS application, this database services a wide variety of needs. In time, the database will be expanded to include maps in a variety of scales, as well as other format types of geospatial data."

Don Gramlich, Lead Programmer Analyst in the UB Libraries, provided technical support for the development of the database.

For questions or assistance with the NYS Gazetteer and GeoData Collection, Ms. Shular can be reached in the UB Libraries by email mshular@buffalo.edu, or by phone at 645-2947 x223.

(Thanks to Data Detective Michael R. Lavin of the University at Buffalo.)