MCDC News and Updates

Tag: application

119th Congressional Districts and 2024 State Legislative Districts Now Available in Geocorr 2022

Posted on by glenn

New in the Geocorr 2022 application this month: We’ve added the 119th congressional districts and 2024-vintage state legislative districts.

  • Five states (Alabama, Georgia, Louisiana, New York, and North Carolina) redrew their congressional district plans for the 119th Congress.
  • Eight states (Georgia, Minnesota, Montana, North Carolina, North Dakota, Ohio, Washington, and Wisconsin) had changes to both their upper (senate) and lower (house) state legislative districts.
  • Three states (Michigan, New York, and South Carolina) changed only their state house districts.

Also note that the Geocorr input form has been slightly redesigned to accommodate the burgeoning number of geography types. State legislative districts are now grouped under their own sub-heading.

Please report any errors to Glenn Rice (riceg@missouri.edu).

Urban/Rural Categories now available in Geocorr 2022

Posted on by glenn

We’ve added the new urban areas to the Geocorr 2022 application this month.

There are two new options in Geocorr for source or target geographies. Urban areas are the complete areas with Census Bureau codes; for example, the Columbia, MO urban area with UA code 18937. Urban/rural portion uses a binary designation (“U” or “R”) for each block to calculate the fraction of urban and rural population for any other geography.

There are significant changes to the urban/rural classifications for the 2020 Census. One major change is that we no longer have two different types of urban area. Previously, there were urbanized areas and urban clusters (collective called urban areas), but now there are only urban areas of a single type. In addition, the method for defining these areas is much more complex than before. The short version of the new definition, from the Bureau’s Urban and Rural page, is:

For the 2020 Census, an urban area will comprise a densely settled core of census blocks that meet minimum housing unit density and/or population density requirements.  This includes adjacent territory containing non-residential urban land uses.  To qualify as an urban area, the territory identified according to criteria must encompass at least 2,000 housing units or a population of at least 5,000.

Among other factors, the longer definition includes:

  • Initial criteria for blocks: >= 425 dwelling units/ square mile, or substantial impervious surface >= 20%, or group quarters facility and >= 500 population/square mile.
  • Candidate blocks are then assembled into urban areas:
    • Start with an initial contiguous core area with >= 500 dwelling units.
    • Add nearby noncontiguous urban blocks: any number of “hops” <= 0.5 mile over land area, and up to one “jump” of 0.51 – 1.5 miles over land area.
  • Combined urban area must have at least 5,000 population or at least 2,000 housing units.
  • Enclaves or surrounded areas are added (or removed), and additional qualifying criteria (airports, indentations, high-employment areas, impervious areas) are applied.

For a complete list of elements comprising the new definition, refer to the Federal Register Notice. See also this helpful PDF, Differences between the Final 2020 Census Urban Area Criteria and the 2010 Census Urban Area Criteria, for more information about the changes.

Please report any errors to Glenn Rice (riceg@missouri.edu).

More Geographies Added to Geocorr 2022

Posted on by glenn

New in the Geocorr 2022 application this month:

We’ve added current American Indian / Alaska Native / Native Hawaiian areas. These areas include American Indian reservations (state and federal), off-reservation trust lands, Hawaiian home lands (HHLs), joint-use areas, Oklahoma tribal statistical areas (OTSAs), Alaska native village statistical areas (ANVSAs), state designated tribal statistical areas (SDTSAs), and tribal designated statistical areas (TDSAs). Alaska Native Regional Corporations [ANRCs] and tribal subdivisions are not included in MABLE/Geocorr.

The Bureau released block equivalency files for 118th congressional districts and 2022 state legislative districts this month — two months early! — so we’ve replaced the “provisional” CD/SLDs with these new “official” ones.

The next major addition to Geocorr will be the new urban/rural classifications, expected December 2022 or January 2023. There are significant changes to the urban/rural classifications for the 2020 Census — we’ll post more about that later, but if you’re interested, the Bureau’s Urban and Rural page has more detail.

Please report any errors to Glenn Rice (riceg@missouri.edu).

Geocorr 2022: Now With 2020 (and 2010) PUMAs

Posted on by glenn

We’ve added several new geography types to the Geocorr 2022 application. The new 2020-vintage PUMAs (public use microsample area), released just a few weeks ago, are now available. By request, we’ve also restored the 2010-vintage PUMAs to facilitate crosswalks.

Because the new PUMAs are based on the 2020 census but were released in 2022, we’re interchangeably calling them 2020 and 2022 PUMAs. (This is the same way we handled the 2010/2012 PUMAs.)

For more information about PUMAs, please refer to our “All about PUMAs” page (now due for a revision!) or the Census Bureau’s PUMA reference.

As usual, please report any errors to Glenn Rice (riceg@missouri.edu).

Post-Redistricting Geographies Now Available in Geocorr 2022

Posted on by glenn

Geocorr 2022 just got better!

Many of our users have been asking when the new, post-Census-2020 Congressional districts would be available in Geocorr. The short answer is that 118th CDs are now included in Geocorr 2022, along with current state legislative districts.

A somewhat longer answer is that the U.S. Census Bureau has not yet released shapefiles or block lists for building 118th CDs or current SLDLs or SLDUs from 2020 tabulation blocks — and is not planning to do so for several months yet.

The Bureau’s Redistricting Data Office (RDO) intends to publish block equivalency files for the 118th Congress and for the 2022 state legislative districts, but not until December of 2022 at the earliest. And, the Bureau’s Geography division will not be releasing block allocation files for the same areas at all. However, the new areas will be published as shapefiles in the cartographic boundary files collection around April or May of 2023. They may also be released with the 2022 TIGER/Line shapefiles, generally around October.

Because of this lack of availability, we obtained new CD and state legislative boundary shapefiles from The American Redistricting Project, merged them, and ran intersections against 2020 TIGER/Line block shapefiles to determine how every block fits into the new districts. This was a tedious process, especially since the block and district shapefiles didn’t line up exactly, but we now have enough data to use for correlations.

With all that said, the new legislative geographies in Geocorr 2022 should be considered provisional until such time as they can be verified via official Census Bureau block equivalency files or shapefiles.

Of lesser interest (mainly for our Missouri users), Geocorr 2022 now also includes the most recent MO library districts.

As always, please contact Glenn Rice (riceg@missouri.edu) with technical questions.

Geocorr 2022

Posted on by glenn

We’re happy to announce a new version of Geocorr based on 2020 decennial census geographies. Thank you for your patience!

Currently, Geocorr 2022 comprises the following geographies for all states, DC, and PR (where applicable):

  • nation (aka “Entire universe”)
  • states
  • counties
  • minor civil divisions (MCDs; includes townships and other county subdivisions)
  • tracts
  • block groups
  • blocks
  • places (towns, villages, cities, etc.) and census-designated places (CDPs)
  • core-based statistical areas (CBSAs; includes metropolitan and micropolitan statistical areas)
  • upper- and lower-chamber state legislative districts
  • Congressional districts (116th Congress)
  • ZCTAs (ZIP codes)
  • NECTAs and NECTA divisions
  • elementary, secondary, and unified school districts
  • “best” school districts and types
  • county and place size categories
  • hospital service areas and referral regions

In addition, Geocorr 2022 includes the following regions for the state of Missouri only:

  • Regional Planning Commissions
  • University of Missouri Extension regions
  • MO Dept. of Economic Development (MERIC) regions
  • MO Dept. of Transportation districts
  • MO Area Agencies on Aging
  • MO BRFSS regions

We’ll add other geography types as they become available.

Longtime users of the Geocorr applications may notice a few other changes. Geocorr 2022 does not include the concentric ring pseudo-geocode options, nor the bounding box filter option. Our server logs indicated that these options were rarely used, and in a couple of instances were not actually functional. The HTML (web page) report option is now unchecked by default. The report output is the most resource- and time-intensive block of Geocorr’s code, and frequently causes program timeouts when very long reports (e.g., those using blocks) are requested.

Although Geocorr 2022 has been thoroughly tested, it should be considered a “beta” version for the moment. Please report any errors to Glenn Rice (riceg@missouri.edu).

New data application shows population by age and demographics

Posted on by glenn

A new MCDC data application, Population Estimates by Age and Demographics, provides population data at the state and county level for multiple age cohorts, data years, and demographic groups. These data are based on US Census populations with special “bridged race” categories created by the Census Bureau for the National Center for Health Statistics (NCHS).

The new application allows users to select one or more states (including counties, for single-state selections), data years (1990–2015), demographic groups, and age cohorts. There are two predefined age cohort sets, and users may also define up to 20 custom age cohorts, including both single year of age and multi-year age ranges. Age ranges may overlap.

This application complements our other population estimates apps, in particular the Population Trends app, which uses the same NCHS source data to compare population estimates between two data years. However, the Population Trends application is simpler, using only predefined age cohorts and a more limited set of data years and demographic groups. This new application offers more options and an Excel data export feature.

We hope you find this a useful tool. Please contact us with any problems, bugs, or suggestions.