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FAQ & Resources

James Gaboardi edited this page Oct 2, 2020 · 15 revisions
  1. Where can I find detailed information on how the base geographic crosswalks were created?

  2. Where can I download the base geographic crosswalks?

  3. Is there a pseudo-algorithm for the crosswalk generated in nhgisxwalk?

    • Yes. See the General Crosswalk Construction Framework here.
  4. How can I cite the base geographic crosswalks?

  5. Can I use NHGIS crosswalks for block group level data?

    • Yes, this functionality is currently available within nhgisxwalk.
    • For the original idea see here.
  6. Can I use NHGIS crosswalks for tract level data?

    • Yes, this functionality is currently available within nhgisxwalk.
  7. Can I use NHGIS crosswalks for county level data?

    • Yes, this functionality is currently available within nhgisxwalk.
  8. What are "block group parts" and how can I download them?

    • What are "block group parts?"
      • "Block Group Parts" are an alternate of Census Block Groups generated by the NHGIS that are comprised of blocks, but don't follow the standard GEOID structure/hierarchy (State--County--Census Tract).
    • How can I download them "block group parts?"
      • 1990:
        • Navigate to the NHGIS Data Finder.
        • From YEARS select 1990 and then Submit.
        • Click SHOW COMPOUND GEOGRAPHIC LEVELS in the top right of the box.
          • Scroll down to Block Groups
          • Select the Block Group [1990 Partition], which exhibits the following ID structure/hierarchy:
            • (State--County--County Subdivision--Place/Remainder--Census Tract--Congressional District (1987-1993, 100th-102nd Congress)--American Indian/Alaska Native Area/Remainder--Reservation/Trust Lands/Remainder--Alaska Native Regional Corporation/Remainder--Urbanized Area/Remainder--Urban/Rural)
          • The NHGIS code for this data product is 598_101.
          • Click Submit.
        • Select the desired data through TOPICS and SELECT DATA.
        • Click CONTINUE in the upper right two times.
        • Select a geographic level from GEOGRAPHIC EXTENTS (## of 51 SELECTED) then Submit.
      • 2000:
        • Navigate to the NHGIS Data Finder.
        • From YEARS select 2000 and then Submit.
        • Click SHOW COMPOUND GEOGRAPHIC LEVELS in the top right of the box.
          • Scroll down to Block Groups
          • Select the Block Group [2000 & 2010 Partition], which exhibits the following ID structure/hierarchy:
            • (State--County--County Subdivision--Place/Remainder--Census Tract--Urban/Rural))
          • The NHGIS code for this data product is 090.
          • Click Submit.
        • Select the desired data through TOPICS and SELECT DATA.
        • Click CONTINUE in the upper right two times.
        • Select a geographic level from GEOGRAPHIC EXTENTS (## of 51 SELECTED) then Submit.
  9. How are the crosswalks sorted?

    • Crosswalks are sorted (see pandas.DataFrame.sort_values()) first by the source then target columns in ascending order with missing (NaN/null) values placed last. These parameters are defined for all sorts performed within nhgisxwalk with the SORT_PARAMS variable.
  10. Still have a question?

    • Ask here in the IPUMS/NHGIS User Forum.