Keywords Boundaries United States
Procedures_Used: The data was extracted from Census TIGER/line files stored on 38 compact discs (CD) using the following four step procedure:
1) Copy the data off the TIGER/line CD onto magnetic disc of a Data General 6220 server. The data was copied on a per state basis under an individual directory.
2) Run the data through ARCTIGER.AML which goes as follows:
/* ARCTIGER.AML - An aml that will extract county outer boundary lines from /* Census TIGER line files and MAPJOIN these lines to create a /* full state coverage of county lines. Directory must contain /* albers.prj Projection file. /* ----------------------------------------------------------------------- /* Read county list from a particular state and set # of iterations to the /* # of counties. &args stno state &setvar countycount [filelist /gis/%stno%[unquote '/*'] county.list -full -dir] &setvar fileunit [open county.list ostat -r] &do i = 1 &to %countycount% /* Read individual TIGER files. &setvar cty [locase [read %fileunit% rstat]] &setvar xyz [filelist %cty%/tgr* tigerfiles -full -file] &setvar filunit [open tigerfiles ostat -r] &sv fname [locase [read %filunit% rstat]] &sv statecounty [substr %fname% 16 5] /* Block TIGER file record 1 and perform SORTTIGER. &if [after %fname% .] = f21 &then &sys dd if=%fname% of=line%statecounty% ibs=228 obs=228 cbs=228 conv=unblock sorttiger 1 line%statecounty% lnsrt%statecounty% &sv fname [locase [read %filunit% rstat]] /* Block TIGER file record 2 and perform SORTTIGER. &if [after %fname% .] = f22 &then &sys dd if=%fname% of=shape%statecounty% ibs=208 obs=208 cbs=208 conv=unblock &sv cerr1 [close %filunit%] sorttiger 2 shape%statecounty% shpsrt%statecounty% /* Create ARC coverage from blocked and sorted TIGER files using the /* TIGERARC command. tigerarc precensus geo%statecounty% lnsrt%statecounty% shpsrt%statecounty% &sys rm line%statecounty% lnsrt%statecounty% shape%statecounty% ~ shpsrt%statecounty% build geo%statecounty% line /* Extract items geo%statecounty%-ID and SOURCE from geo%statecounty%.ACODE /* datafile and add to geo%statecounty%.AAT pullitems [translate geo%statecounty%].ACODE PULL [translate geo%statecounty%]-ID SOURCE END joinitem [translate geo%statecounty%].AAT PULL ~ [translate geo%statecounty%].AAT [translate geo%statecounty%]-ID ~ [translate geo%statecounty%]-ID ORDERED tables $kill PULL q stop /* Project geo%statecounty% into Albers equal area to create prj%statecounty%, /* BUILD with LINE, CLEAN with 10 10 POLY and extract outer boundary to create /* cov%statecounty%. project cover geo%statecounty% prj%statecounty% albers.prj build prj%statecounty% line clean prj%statecounty% gcl%statecounty% 10 10 poly reselect gcl%statecounty% cov%statecounty% line RESELECT LPOLY# = 1 OR RPOLY# = 1 [unquote ' '] n n build cov%statecounty% line build cov%statecounty% poly /* ADDITEM STATECTY and populate cov%statecounty%.PAT with %statecounty%, /* calculate cov%statecounty%-ID in the cov%statecounty%.AAT to equal SOURCE /* so pseudonodes can be deleted with UNSPLIT in ARCEDIT, then set all /* cov%statecounty%-ID's in cov%statecounty%.AAT to equal /* cov%statecounty%#. createlabels cov%statecounty% build cov%statecounty% poly additem [translate cov%statecounty%].PAT [translate cov%statecounty%].PAT ~ STATECTY 5 5 I tables select [translate cov%statecounty%].PAT reselect [translate cov%statecounty%]# GT 1 calc STATECTY = %statecounty% select [translate cov%statecounty%].AAT reselect SOURCE CN ' ' calc [translate cov%statecounty%]-ID = 0 aselect reselect SOURCE CN 'A' calc [translate cov%statecounty%]-ID = 1 aselect reselect SOURCE CN 'B' calc [translate cov%statecounty%]-ID = 2 aselect reselect SOURCE CN 'C' calc [translate cov%statecounty%]-ID = 3 aselect reselect SOURCE CN 'D' calc [translate cov%statecounty%]-ID = 4 aselect reselect SOURCE CN 'E' calc [translate cov%statecounty%]-ID = 5 aselect reselect SOURCE CN 'F' calc [translate cov%statecounty%]-ID = 6 aselect reselect SOURCE CN 'G' calc [translate cov%statecounty%]-ID = 7 q stop idedit cov%statecounty% line arcedit ec cov%statecounty% ef arcs select all unsplit save quit build cov%statecounty% line build cov%statecounty% poly tables select [translate cov%statecounty%].AAT calc [translate cov%statecounty%]-ID = [translate cov%statecounty%]# q stop idedit cov%statecounty% line kill geo%statecounty% all kill prj%statecounty% all kill gcl%statecounty% all &end &setvar cerr2 [close %fileunit%] &sys rm county.list &sys rm tigerfiles /* MAPJOIN the individual county coverages to form a full state coverage. &setvar covercount [filelist cov* covlist -cover -network] &setvar fileunit [open covlist ostat -r] mapjoin %state% net features &do i = 1 &to %covercount% &setvar cover [read %fileunit% rstat] %cover% &end end &sys rm covlist /* Set SOURCE codes equal to cover-ID so pseudonodes can be removed with /* UNSPLIT in ARCEDIT. tables select [translate %state%].AAT reselect SOURCE CN ' ' calc [translate %state%]-ID = 0 aselect reselect SOURCE CN 'A' calc [translate %state%]-ID = 1 aselect reselect SOURCE CN 'B' calc [translate %state%]-ID = 2 aselect reselect SOURCE CN 'C' calc [translate %state%]-ID = 3 aselect reselect SOURCE CN 'D' calc [translate %state%]-ID = 4 aselect reselect SOURCE CN 'E' calc [translate %state%]-ID = 5 aselect reselect SOURCE CN 'F' calc [translate %state%]-ID = 6 aselect reselect SOURCE CN 'G' calc [translate %state%]-ID = 7 q stop idedit %state% line arcedit ec %state% ef arcs select all unsplit save quit build %state% poly build %state% line /* Set cover-ID's back to equal cover#. tables select [translate %state%].AAT calc [translate %state%]-ID = [translate %state%]# q stop idedit %state% line /* Remove sliver polygons while retaining SOURCE codes. createlabels %state% 1001 build %state% poly pullitems [translate %state%].AAT PULL [translate %state%]-ID SOURCE END eliminate %state% el%state% # poly RESELECT [translate %state%]-ID > 1000 [unquote ' '] n n build el%state% line build el%state% poly kill %state% all rename el%state% %state% joinitem [translate %state%].AAT PULL [translate %state%].AAT ~ [translate %state%]-ID [translate %state%]-ID LINEAR tables $kill PULL q stop &return
3) Visually check the data for accuracy against the 1:2,000,000 county boundaries. When discrepancies occured, the data was checked against USGS 1:100,000 quad maps.
Revisions: Process_Step Process_Description None to date. Process_Date
Reviews_Applied_to_Data: Post-processing data review performed as mentioned above by Mark Negri.
Related_Spatial_and_Tabular_Data_Sets:
Other_References_Cited: Lines with SOURCE code type 'X' were obtained by bufferring USGS 1:2,000,000-scale digital map of counties, 1985.
Notes:
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(Here you pick one of the following entries that describes how often changes or additions are made to the data set. Pick one, and delete the rest)
Continually Daily Weekly Monthly Annually Unknown As Needed Irregular None planned
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There are no shorelines in this coverage. Coastal states have their boundaries extended approximately 3 miles into the ocean. States that bound the Great Lakes and other large inland waterbodies have their boundaries extended proportionally into the waterbody.
(Here you acknowledge the agencies and organizations that gave you money, resources, and encouragement to digitize the data and to enter all this wonderful metadata.)
(Information in wordy narrative form describing omissions, selection criteria, generalization, definitions used, and other rules applied to derive the data set)
(An explanation of the accuracy of the horizontal coordinate measurements and a description of tests used, if any, to determine horizontal positional accuracy. This is different from horizontal resolution as reported in the DOC file. Positional accuracy defines how correctly the digital features match real-world features and woiuld be related to the concept of the National Map Accuracy Standard -- xx% of well-defined point features fall within xx units of their true position. The resolution is the smallest unit of measure the GIS can reliably manage without truncation or rounding.)
(The same as above, but for vertical information that may be encoded with the 2-D features such as cell or contour estimates of a vertical dimension. A description of the contour interval of input data and its basis could be described here.)
Value Description ------- ------------------------------------ (Blank) Nondocumented A 1980 GBF/DIME-file B USGS 1:100,000-Scale DLG-3 File C Other USGS Map D Census Bureau Precensus Update X USGS-WRD Shoreline Buffer
All arcs are encoded by a BNDYTYPE (boundary type) code as follows (As of 06/24/91, codes 0, 3 and 4 have not been populated yet):
0 - Coastline of the United States.
1 - State-state border occurring on land.
2 - County-county border, within state, occurring on land.
3 - State-state border occurring on the ocean, estuary, or a Great Lake. Some of these borders are arbitrary.
4 - County-county border, within state, occurring on the ocean, estuary, or a Great Lake. Some of these borders are arbitrary.
5 - International border occurring on land.
6 - International border occurring on water.
7 - U.S. Census shoreline buffer (approximately 3 miles).
8 - USGS-WRD shoreline buffer (SOURCE code 'X').
As of 06/21/91, the frequency of BNDYTYPE is as follows: