This website provides year-to-year compatible map series showing the evolution of racial geography in 63 major American cities (a complete list of MSA is available here). Each series starts from the earliest year for which racial data (at the census tract level) is available for a given city (no later than 1950) and continues until 2010. The earliest series started in 1910. Census classification of race/ethnicity has changed over the 1910-2010 period. Our goal is to use a single classification over this entire period. However, this proved to be impossible. Thus, we use two sets of racial classification. The classification for years 1910-1970 uses three racial categories (White, Blacks, Asians (including also American Indians)). The classification for years 1980-2010 uses five racial categories (Non-Hispanic Whites, Non-Hispanic Blacks, Non-Hispanic Asians (including American Indians), Non-Hispanic Others, and Hispanic/Latino origin population).
To show how race composition changes in US major cities, we use a diversity/dominant type map because it presents the most information in a single map. Comparing the maps between years, viewers have to keep in mind two main changes in the race categorizations:
- Hispanic origin population until 1970 was included in the White category and since 1980 constitute as a separate category;
- Data for 1940 distinguish only between White and Non-White population; we assign Non-White population to Black; in some cases, it leads to depicting Asian population incorrectly (i.e., Chinatown in San Francisco in 1940 will be incorrectly depicted as Black dominated area).
Detailed information about this dataset is described in
Anna Dmowska, and Tomasz Stepinski. 2021. “Long-time Series of Racial Maps with a Time-invariant Legend.” SocArXiv. October 17. doi:10.31235/osf.io/untx3. [preprint]
EXAMPLES OF YEAR-TO-YEAR COMPATIBLE MAPS FOR SELECTED CITIES
Click on the name of the city to open a PDF file with the series of diversity/dominant race types maps showing how the racial topography change over the years. Maps for the other cities can be downloaded below as a zip archive.
WHAT IS INCLUDED IN OUR RESOURCES?
- Zip archives contain an ESRI shapefile of census tracts with a numerical database detailing the racial statistics for each tract (a headcount of each racial subpopulation, a share of each racial subpopulation, and the label of diversity/dominant race type classification). In our dataset, all census tracts were harmonized to 2010 boundaries to unable tracking changes between years at the neighborhood level. The default spatial display is the map of diversity/dominant race types. Maps of other variables (i.e., percentage of a given race) can be easily obtained using the GIS software. The name of the zip archive is, for example, "norm_chicago_il. zip". It contains the name of MSA (i.e., Chicago) and the 2-letters state code (i.e., il).
- Zip archive consists of the set of the maps, plots, and summary tables in PDF and MS Excel format prepared for the metropolitan statistical area (MSA) and the main county within MSA (for example, files for Chicago, IL MSA, and Cook County, IL). The name of the zip archive is, for example, "ct_chicago_il_pdf.zip." It contains the name of MSA (i.e., Chicago) and the 2-letters state code (i.e., il). The maps included in the PDF files are based on the census tract's boundaries for a given year.
Included are four types of files (files for MSA start with the prefix “msa_”; files for the county begins with the prefix “cnt_”:
- PDF files with a series of diversity/dominant race types map showing how the racial topography change over the years (i.e., msa_chicago_oh.pdf; cnt_chicago_oh.pdf)
- PDF files showing the evolution of racial composition (percentage of people of a given race) in the form of a barplot (the number in the bars indicates the percentage of the total population of a given race in a given year).
- PDF files showing the distribution of census tracts of different types (percentage of census tracts in a given diversity/dominant type) in the form of a barplot (the number in the bars indicates the percentage of census tracts in a given diversity/dominant type). (i.e, msa_chicago_il_perc_tract.pdf; cnt_chicago_il_perc_tract.pdf)
- MS Excel files with two sheets: perc_tract contains a percentage of census tracts in a given diversity/dominant type for the available years; perc_race contains a percentage of a given race for the available years. (i.e, msa_chicago_il.xls; cnt_chicago_il.xls)
DOWNLOADING HISTORICAL CENSUS TRACTS FOR INDIVIDUAL MSAs
- From the dropdown menu, select the name of the metropolitan area. Click on the "Download" button to download a zip archive. For example, the name of the zip archive is "norm_chicago_il.zip" for downloading data in ESRI Shapefile format and ct_chicago_il_pdf.zip for downloading a set of maps and plots in PDF file format. It contains the name of MSA (i.e., Chicago) and the 2-letters state code (i.e., il).
- Unzip a downloaded zip archive.
- In case of downloading data (i.e., norm_chicago_il.zip), the directory will contain ESRI Shapefile and the QGIS legend file with the color scheme for displaying racial diversity/dominant race classification. By default, the classification for 2010 is displayed. To display a map for another year user has to go to the Symbology window in QGIS and change the name of the displayed variable (i.e., DIV_1930 will display a map for a 1930 year).
- In case of downloading PDF files (i.e., ct_chicago_il_pdf.zip), the directory will contain a set of PDF and MS Excel files (see section What is included in our resources?)
Select the name of the Metropolitan area from the dropdown menu below and click "Download" to download the zip archive containing data in the ESRI Shapefile format
Select the name of the Metropolitan area from the dropdown menu below and click "Download" to download the zip archive containing the set of the maps, plots, and summary tables in PDF and MS Excel format
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