Why can’t I select to download data for a single county or a single MSA in NHGIS?
This is one of the biggest changes that experienced users of NHGIS may notice about the new site. Unlike the old NHGIS website, users no longer specify a particular area they wish to download data for, but instead receive data for the entire country (or state when working at the block or block group level). For example, if interested in data for Hennepin County, Minnesota, you need no longer select Minnesota and then Hennepin County. Instead, you simply download county-level data for the entire United States. Then you can isolate Hennepin County in the software you use to analyze the data.
NHGIS made this change for a number of reasons, primarily in the interest of standardizing the selection interface for all years and geographic levels. Giving users the ability to select data from multiple years and data from previously unavailable “compound” geographic levels makes it difficult to support selection by specific geographic extent. Data from different years or from compound geographic levels do not consistently nest within a static set of selectable areas. In addition, a frustration frequently voiced by users of the legacy site was that it was too easy to narrow in on a location and download the tables for that area, but then later decide to get the same data for another area, which turned out to be time-consuming and “clunky.” Finally, removing the need to select a geographic extent simply shortens the time it takes users to create an extract.