= LEHD Public Use Shapefile Data Heath Hayward, Matthew Graham, Lars Vilhuber 21 August 2017 // a2x: --dblatex-opts "-P latex.output.revhistory=0 --param toc.section.depth=3" :ext-relative: {outfilesuffix} ( link:lehd_shapefiles.pdf[Printable version] ) [IMPORTANT] .Important ============================================== This document is not an official Census Bureau publication. It is compiled from publicly accessible information by Lars Vilhuber (http://www.ilr.cornell.edu/ldi/[Labor Dynamics Institute, Cornell University]). Feedback is welcome. Please write us at link:mailto:lars.vilhuber@cornell.edu?subject=LEHD_Shapefiles[lars.vilhuber@cornell.edu]. ============================================== Scope ----- The public-use data from the Longitudinal Employer-Household Dynamics Program, including the Quarterly Workforce Indicators (QWI) and Job-to-Job Flows (J2J), are available for download according to link:lehd_public_use_schema{ext-relative}[structural] and link:lehd_csv_naming{ext-relative}[file naming] schema. The data themselves are available as Comma-Separated Value (CSV) files through the LEHD website's Data page at http://lehd.ces.census.gov/data/ as well as through the http://ledextract.ces.census.gov/[LED Extraction Tool]. Shapefiles are used to provide mapping functionality in http://qwiexplorer.ces.census.gov/[QWI Explorer] and https://j2jexplorer.ces.census.gov/[Job-to-Job Explorer (Beta)]. They are created by transforming input shapefiles sourced from https://www.census.gov/geo/maps-data/data/tiger-line.html[TIGER/Line]. New TIGER/Line shapefiles are typically released by the Census Bureau's Geography Division in August of each year, which are then processed by the LEHD program as new tabulation areas for the QWI[http://lehd.ces.census.gov/data/#qwi] and J2J[http://lehd.ces.census.gov/data/#j2j] data products. The LEHD shapefiles will be made available in the data schema in coordination with the public release of QWI and J2J data products, usually in November or December of each year. Sources ------- Files are derived from  https://www.census.gov/geo/maps-data/data/tiger-line.html[TIGER/Line 2016 shapefiles]: * http://www2.census.gov/geo/tiger/TIGER2016/STATE/[tl_2016_us_state] * http://www2.census.gov/geo/tiger/TIGER2016/COUNTY/[tl_2016_us_county] * http://www2.census.gov/geo/tiger/TIGER2016/CBSA/[tl_2016_us_cbsa] * http://www2.census.gov/geo/tiger/TIGER2016/PLACE/[tl_2016_(ST)_place] (for creation of WIA/WIB shapefile) * http://www2.census.gov/geo/tiger/TIGER2016/COUSUB/[tl_2016_(ST)_cousub] (for creation of WIA/WIB shapefile) Transformations --------------- The following major transformations are applied to the input files: * All geographies are reprojected to http://spatialreference.org/ref/epsg/wgs-84/[WGS-1984 Geographic Coordinate System] * Shoreline water has been clipped out to provide a more recognizable depiction of the coastlines. * Each layer is given internal point coordinates (stored as double) based on the WGS-1984 projection (decimal degrees). * Each layer is run through a "simplify polygon" procedure to remove unnecessary complexity from the features. * Features from Guam, American Samoa, and the Northern Mariana Islands have been removed because they are not used in current LEHD tabulations. * Each shapefile's attribute table has been updated to conform to the standard LEHD output format, defined in <> section Outputs ------- Output shapefiles – grouped by paired products – are listed below. Each shapefile includes specific notes on its preparation. Basic Naming Schema ------------------- All files follow the following naming convention: -------------------------------- [type]]_[geocat].zip -------------------------------- where [type] = lehd_shp and link:naming_geocat.csv[geocat] contains [width="60%",format="csv",cols="^1,<4",options="header"] |=================================================== include::naming_geocat.csv[] |=================================================== === [[format]] FORMAT ( link:variables_shp.csv[variables_shp.csv] ) Files are distributed as http://www.digitalpreservation.gov/formats/fdd/fdd000280.shtml[ESRI Shapefiles], packaged as https://en.wikipedia.org/wiki/Zip_(file_format)[ZIP] files. The SHP component of these archives is described here. Other components (dbf, prj, shx) files are not documented here, we refer users to http://www.digitalpreservation.gov/formats/fdd/fdd000280.shtml . [width="60%",format="csv",cols="<2,<2,<5,<5",options="header"] |=================================================== include::variables_shp.csv[] |=================================================== === Values ==== STUSPS ( link:label_stusps.csv[] ) FIPS State Postal Code as per https://www.census.gov/geo/reference/codes/cou.html ==== GEOGRAPHY ( link:label_geography.csv[] ) The valid codes correspond to those listed on link:label_geography.csv[] and link:label_geography_cbsa.csv[]. ==== NAME This is a string that corresponds in general to the 'label' field on link:label_geography.csv[] and link:label_geography_cbsa.csv[]. Minor deviations for ease of exposition are possible. === Common files ==== State ( link:lehd_shp_gs.zip[] ) No transformations occur to this layer other than those listed above. === QWI Geographies ==== County ( link:lehd_shp_gc.zip[] ) * STUSPS is appended to the NAME field so that county names are nationally unique. Example: "Cook, IL" ==== CBSA - within State ( link:lehd_shp_gm.zip[] ) * All features are split into state-specific CBSA features by intersecting each feature with the state shapefile features. * The STUSPS field is added during the intersect with the state shapefile. * STFIPS (i.e. FIPS State Code as per https://www.census.gov/geo/reference/ansi_statetables.html) is prepended to the CBSA code (https://www.census.gov/population/metro/data/def.html) to create the GEOGRAPHY field to distinguish state-parts of the same CBSA (i.e. make them nationally unique). * The text "([STUSPS] part)" is appended to the NAME field only for those CBSA features that are split by state lines. ==== Workforce Investment Board Areas ( link:lehd_shp_gw.zip[] ) The WIA/WIB shapefiles are built from the Place, County Subdivision, and County shapefiles from TIGER/Line based on definitions provided by the LED state partners. === Job-to-Job Flow Geographies ==== Metropolitan (complete) ( link:lehd_shp_gb.zip[] ) * Micropolitan areas are removed and state remainder areas are added as new features. State remainders are assigned unique codes ([STUSPS]+999) and names ("Not in metropolitan area, [STUSPS]"). [[versioning]] Versioning ---------- Versioning rules follow http://semver.org/spec/v2.0.0.html[Semantic Versioning V2.0.0], which states that ________________________________________________________________________________ Given a version number MAJOR.MINOR.PATCH, increment the: * MAJOR version when you make incompatible API changes, * MINOR version when you add functionality in a backwards-compatible manner, and * PATCH version when you make backwards-compatible bug fixes. ________________________________________________________________________________ [[changes]] Changes ------- <<< ******************* This revision: Mon Aug 21 13:16:51 EDT 2017 *******************