= LEHD Public Use Shapefile Data Heath Hayward, Matthew Graham, Lars Vilhuber 12 August 2016 // 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 specification is draft. Feedback is welcome. Please write us at link:mailto:Patrick.Hayward@census.gov?subject=LEHD_Shapefiles[Patrick.Hayward@census.gov]. ============================================== 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 Job-to-Job Explorer (coming soon). They are created by transforming input shapefiles sourced from https://www.census.gov/geo/maps-data/data/tiger-line.html[TIGER/Line]. Sources ------- Files are derived from  https://www.census.gov/geo/maps-data/data/tiger-line.html[TIGER/Line 2015 shapefiles]: * http://www2.census.gov/geo/tiger/TIGER2015/STATE/[tl_2015_us_state] * http://www2.census.gov/geo/tiger/TIGER2015/COUNTY/[tl_2015_us_county] * http://www2.census.gov/geo/tiger/TIGER2015/CBSA/[tl_2015_us_cbsa] * http://www2.census.gov/geo/tiger/TIGER2015/PLACE/[tl_2015_(ST)_place] (for creation of WIA/WIB shapefile) * http://www2.census.gov/geo/tiger/TIGER2015/COUSUB/[tl_2015_(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[]. ==== NAME This is a string that corresponds in general to the 'label' field on link:label_geography.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 ==== CBSA - National ( link:lehd_shp_gb.zip[] ) * The state remainder areas are added to the shapefile as new features. They are assigned unique codes ([STUSPS]+999) and names (“Not in metro/micro 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: Fri Aug 12 14:13:12 EDT 2016 *******************