Battaglin, W.A., and Goolsby, D.A. 1994 1.0 Digital Data Reston, Virginia U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ag_chem Battaglin, W. A.; Goolsby, D. A. 1995 report U.S. Geological Survey Water Resources Investigative Report WRIR 944176 Reston, VA U.S. Geological Survey http://pubs.er.usgs.gov/publication/wri944176 This coverage contains estimates of agricultural-chemical use in counties in the conterminous United States as reported in the 1987 Census of Agriculture (U.S. Department of Commerce, 1989a). Agricultural-chemical use data are reported as either acres on which used, tons, or as a percentage of county area. Agricultural-chemical use estimates were generated from surveys of all farms where $1,000 or more of agricultural products were sold, or normally would have been sold, during the census year. Most of the attributes summarized represent 1987 data, but some information from the 1982 Census of Agriculture also was included. The polygons representing county boundaries in the conterminous United States, as well as lakes, estuaries, and other nonland-area features were derived from the Digital Line Graph (DLG) files representing the 1:2,000,000-scale map in the National Atlas of the United States (1970). Agricultural chemicals Census of Agriculture Counties United States The agricultural-chemical use data in this coverage are intend for use in estimating regional agricultural-chemical use, and in producing visual displays and mapping relative amounts of agricultural-chemical use across broad regions of the United States. Procedures_Used: CENSUS DATA An automated procedure was developed for processing the raw census data into ARC/INFO coverage attributes. The procedure is summarized below: 1) copy county2m coverage to coverage representing type of census data (i.e. ag_expn or ag_land), 2) run agadd.aml for each item added to the coverage, giving coverage name and attribute field number as arguments. The agadd.aml program runs a fortran program to extract field data from the raw census data files, and then processes that raw data finally adding it as a column of attribute data to the county coverage. Other programs were developed to calculate summary statistics of the census attribute data, and to make graphics representing attribute values across the United States. COUNTY BOUNDARIES This series of maps was published as part of the National Atlas of the United States (U.S.Geological Survey, 1970). The maps for the conterminous United States were digitized in 15 sheets and published in the Digital Line Graph (DLG) format as described by Domeratz and others (1983). Each sheet was prepared by reading the DLG files of the political and water bodies layers, converting them to ARC/INFO, extracting the county boundaries and the coastline, respectively, and joining the two layers. FIPS codes were assigned to all polygons by using available sources and were checked manually. Boundaries with adjacent sheets of the 15-sheet set were edgematched manually, arbitrarily choosing one of the sheets as the "correct" border. Edgematching operations adjusted the linework as far as was necessary so that the coverages would fit to a tolerance of 100 meters. The coverage (referred to herein as Version 1.0) was stored as 49 separate coverages (48 States and the District of Columbia) because the ARC/INFO software in use at the time could not process the entire coverage. Individual States could be joined by specifying a tolerance of 100 meters. From time to time, adjustments were made to the State coverages to reflect changes in U.S. counties. It is believed the accuracy of these adjustments is comparable to the original linework. For Version 2.0, all State coverages were rejoined and manually edited to produce a perfect edgematch between all States. For States on the original map sheet boundaries, this adjustment averaged less than 20 meters and in no case was more than 100 meters. The whole coverage was CLEANed to a tolerance of 20 meters, which resulted in few, if any, effects on small offshore islands. The coverage also was checked to ensure that it represented current U.S. counties or county equivalents. The coverage in Version 1.0 stopped at the coastline. There was no attempt to depict offshore areas. This created some problems when the coverage was used to assign county codes to sampling stations located near the coast. To help in this matter, Version 2.0 includes offshore extensions of the county polygons. The (water) boundaries of many of these polygons are arbitrary. The Canadian Great Lakes features are another new addition to Version 2.0. They were added to improve the utility of the coverage for visual displays. Although the Canadian Great Lakes are logically represented by a single polygon, practical considerations -- the inability of some software to plot polygons with a large number of vertices -- made it necessary to separate them into four polygons. The dividing lines are located in narrow channels to minimize interference with plotting patterns. Canadian islands within the Great Lakes also were included. All ticks were relocated to places that are easily visible on maps of the United States, to help in registering maps that may not otherwise have adequate registration information. To expedite accessing parts of the coverage, certain items have been indexed with the procedure, INDEX_COUNTY.AML. See Section 3 above. A spatial index also was created. When using this coverage to clip or intersect other coverages, a tolerance as low as 2 meters can be used. The processing used to derive this coverage moved boundaries from their positions on the original maps. In cases of conflicting lines, preference was given to forming the correct topology. Strictly speaking, this coverage is not identical to the source materials. These changes were unavoidable in producing a continuous coverage of the conterminous United States. Revisions: COUNTY POLYGON DATA Revision 1.0, 12/17/90. This revision represents numerous corrections and minor modifications made to this set of coverages from its construction in 1985 through the revision date. Process_Date 12/17/90 Revision 2.0, 3/18/91. Major reworking of the coverage, combining all State coverages. Process_Date 3/18/91 Reviews_Applied_to_Data: The Census of Agriculture data processing procedure and attribute data have been peer reviewed in 1993 by Leonard Orzol and Barbara Ruddy, both hydrologist with the USGS. The county boundaries in this coverage have received no formal review They have, however, been used in numerous applications where serious errors would have been obvious. Some State coverages were corrected following such use. The offshore polygon extensions and the Canadian Great Lakes polygons have had no review. Related_Spatial_and_Tabular_Data_Sets: This coverage is part of series of 1:2,000,000-scale base maps covering the United States. Layers in this set include: COUNTY -- County boundaries. STATE -- State boundaries (formed from COUNTY). WATERBOD -- Water Bodies. STREAM -- Streams. HUC -- Hydrologic cataloging units (basins). Other_References_Cited: Domeratz, M. A., Hallam, C. A., Schmidt, W. E., and Calkins, H. W., 1983, USGS Digital Cartographic Data Standards: Digital Line Graphs from 1:2,000,000-scale Maps. U.S. Geological Survey Circular 895-D, 38p. Nebert, Douglas D., 1994, Design of the distributed spatial data library for the Water Resources Division, U. S. Geological Survey: U. S. Geological Survey Open-File Report, 94-327, 30 p. U.S. Department of Commerce, 1989a, Census of agriculture, 1987 -- Final county file: U.S. Department of Commerce, Bureau of the Census, [machine-readable data file] U.S. Department of Commerce, 1989b, Census of agriculture, 1987 -- Final county file technical documentation: U.S. Department of Commerce, Bureau of the Census, Data User Services Division. U.S. Department of Commerce, 1990, Census of agriculture, 1987 -- Agricultural atlas of the United States, volume 2: U.S. Department of Commerce, Bureau of the Census, Agriculture Division, AC87-S-1, 210 p. U.S. Geological Survey, 1970, National atlas of the United States of America: Washington D.C., U. S. Geological Survey, 417 p. Notes: DOCUMENTATION The documentation for this coverage was generated by using the ARC macro language (AML) program document.aml available from the U.S. Geological Survey (Nebert, 1994). 1987 1994 Complete As Needed -128.07002717 -65.25698378 48.26194027 22.67774911 None Agricultural chemical use in counties from 1987 Census of Agriculture inlandWaters None Conterminous United States None None None None None CENSUS DATA Estimates of agricultural-chemical use by county were reported by the U.S. Department of Commerce (1989a, 1898b) in the 1987 Census of Agriculture. The estimates were constructed from surveys of all farms where $1,000 or more of agricultural products were sold, or normally would have been sold, during the census year. Sampling and statistics were used to account for nonresponding farm operations. Thus, the information in the Census of Agriculture is subject to sampling variability as well as reporting and coverage errors. Census disclosure rules prevent publication of information that would disclose the operation of individual farms. Thus, for example, one or two sod farms may be reported in a county, but no acreage of sod harvested is reported, because release of that information might disclose information about a particular farmer's operation. COUNTY BOUNDARIES The original files for this map were provided in 15 sections. Boundaries near the edges of sections have been adjusted in edgematching. Polygons that extend into the water (an ocean or the Great Lakes) should be considered arbitrary. William A. Battaglin U.S. Geological Survey, Water Resources Div. (WRD) Hydrologist, Office of the Regional Hydrologist mailing address

P.O. Box 25046

Denver Federal Center, Bldg. 25

Lakewood CO 20192 USA 1-888-275-8747 303-236-5959 wbattagl@usgs.gov 8:00am-4:30pm MST Please contact thru email http://water.usgs.gov/GIS/browse/ag_chem.gif Illlustration of data set GIF U.S Geological Survey) None Unclassified None dgux, 5.4R3.10, AViiON UNIX, ARC/INFO version 7.0.4 See Entity_Attribute_Information See Explanation Attribute accuracy is described, where present, with each attribute defined in the Entity and Attribute Section. Polygon and chain-node topology present. complete The resolution is the smallest unit of measure the GIS can reliably manage without truncation or rounding. approx. 1.0 km. 1.0 km The vertical information that may be encoded with the 2-D features such as cell or contour estimates of a vertical dimension. Unspecified 1994 2,000,000 Unspecified 1994 Unspecified Unspecified Unspecified RESELECT COUNTY2M COUNTY.NEW POLY None 19911112 1528 None LABELERRORS COUNTY.NEW None 19911112 1529 None LABELERRORS COUNTY.NEW None 19911112 1556 None EXTERNALALL None 19911112 1721 None RENAME COUNTY.NEW COUNTY2M None 19911113 1249 None CREATELABELS COUNTY2M 5000 None 19911115 1656 None EXTERNALALL None 19911204 1410 None COPY COUNTY2M /ARC3/WORK/LIB/COUNTY2M None 19920102 0833 None COPY /ARC3/WORK/LIB/COUNTY2M COUNTY.AG None 19920102 1527 None RENAME COUNTY.AG CNTY.AG None 19920102 1527 None COPY /ARC3/WORK/CNTY.AG COUNTY2M None 19920107 1423 None EXPORT COVER COUNTY2M COUNTY2M None 19920117 1350 None COPY /ARC3/WORK/LIB/COUNTY2M COUNTY2M None 19920121 1549 None BUILD COUNTY2M POLY None 19920121 1615 None ARCEDIT /ARC3/WORK/COUNTY2M None 19920122 0948 None BUILD COUNTY2M POLY None 19920122 0956 None IDEDIT COUNTY2M POLY None 19920122 1101 None COPY COUNTY2M /ARC3/WORK/LIB/COUNTY2M None 19920122 1102 None IDEDIT COUNTY2M POLY None 19920330 1537 None EXPORT COVER COUNTY2M COUNTY2M None 19920608 1103 None ARCEDIT /ARC3/WORK/LIB/COUNTY2M None 19920803 1748 None BUILD COUNTY2M POLY None 19920803 1758 None CLEAN COUNTY2M # 2 2 POLY None 19920803 1846 None COPY COUNTY2M /WB2/DB/USA/COUNTY2M None 19920804 0919 None COPY /WB2/DB/USA/COUNTY2M AG_CHEM None 19930104 1648 None DOCUMENT AG_CHEM DELETE WBATTAGL None 19930329 0947 None DOCUMENT AG_CHEM UPDATE WBATTAGL None 19930329 1049 None DOCUMENT AG_CHEM UPDATE WBATTAGL None 19930329 1118 None DOCUMENT AG_CHEM UPDATE WBATTAGL None 19930329 1350 None EXPORT COVER AG_CHEM AG_CHEM None 19930330 1041 None COPY /ARC3/EPA1/CENSUS/AG_CHEM AG_CHEM None 19941227 1317 None PROJECTDEFINE COVER AG_CHEM None 19941227 1318 None DOCUMENT AG_CHEM UPDATE WBATTAGL None 19941227 1500 None DOCUMENT AG_CHEM UPDATE WBATTAGL None 19941230 1125 None MNEGRI IMPORT COVER AG_CHEM.E00 AG_CHEM None 19950307 1009 None Unspecified None 19950307 1022 None MNEGRI EXPORT COVER AG_CHEM AG_CHEM.E00 None 19950309 1510 None MNEGRI EXPORT COVER AG_CHEM AG_CHEM.E00 None 19950309 1524 None MNEGRI ARCSDTS AG_CHEM AG_CHEM.TAR.GZ PREF None 19950309 1540 None MNEGRI EXPORT COVER AG_CHEM /SCRATCH_AREA1/MNEGRI/AG_CHEM.E00 NONE None 19950919 1453 None MNEGRI EXPORT COVER /DSDL1/CUSA/TILES/CUSA/AG_CHEM AG_CHEM.E00 None 19960624 0814 None MNEGRI EXPORT COVER /DSDL1/CUSA/TILES/CUSA/AG_CHEM AG_CHEM.E00 None 19960625 1044 None Vector Point 4787 String 11926 GT-polygon composed of chains 4788 Albers Conical Equal Area 29.5 45.5 -96 23 0.0 0.0 coordinate pair 1.0 1.0 METERS Unknown Clarke 1866 6378206.4 294.98 AG_CHEM.PAT Polygon attribute table ARC/INFO file AREA Area of polygon in square coverage units (meters) Computed Positive real numbers unspecified unspecified PERIMETER Perimeter of polygon in coverage units (meters) Computed Positive real numbers unspecified unspecified AG_CHEM# Internal feature number Computed Sequential unique positive integer unspecified unspecified AG_CHEM-ID User-assigned feature number User-defined Integer unspecified unspecified FIPS 5-digit County FIPS code Federal Information Processing Standard 01001 - 56998, none = 0 unspecified unspecified ST two-character state abbreviation U.S. Postal Service AL - WY, none = blank unspecified unspecified CNTYNAME County name U.S. Geological Survey Files upper-case alphanumeric, none = blank unspecified unspecified PLYTYPE polygon type: 0=county land, others are lakes, estuaries, etc. see narrative 0-4,9 unspecified unspecified WORKB variable used for data processing n/a any integer unspecified unspecified AREA.ACRES total county land area (all polygons) in acres calculated from areas of polygons with like FIPS code and PLYTYPE=0 numeric values greater than 0, missing = -99.000 unspecified unspecified CA0772 Commercial fertilizer, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0772 Percent of county treated with commercial fertilizer, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0773 Commercial fertilizer, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0773 Percent of county treated with commercial fertilizer, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0776 Cropland fertilized, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0776 Percent of county as cropland fertilized, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0777 Cropland fertilized, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0777 Percent of county as cropland fertilized, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0780 Pastureland and rangeland fertilized, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0780 Percent of county as pastureland and rangeland fertilized, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0784 Lime, 1987 (acres on which used) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0784 Percent of county treated with lime, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0786 Lime, 1987 (tons) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified CA0790 Chemicals used to control insects on hay and other crops, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0790 Percent of county treated to control insects on hay and other crops, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0791 Chemicals used to control insects on hay and other crops, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0791 Percent of county treated to control insects on hay and other crops, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0794 Chemicals used to control nematodes in crops, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0794 Percent of county treated to control nematodes in crops, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0795 Chemicals used to control nematodes in crops, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0795 Percent of county treated to control nematodes in crops, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0798 Chemicals used to control diseases in crops and orchards, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0798 Percent of county treated to control diseases in crops and orchards, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0799 Chemicals used to control diseases in crops and orchards, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0799 Percent of county treated to control diseases in crops and orchards, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0802 Chemicals used to control weeds or grasses in crops, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0802 Percent of county treated to control weeds or grasses in crops, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0803 Chemicals used to control weeds or grasses in crops, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0803 Percent of county treated to control weeds or grasses in crops, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0806 Chemicals used for defoliation or growth control in crops, 1987 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0806 Percent of county treated for defoliation or growth control in crops, 1987 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified CA0807 Chemicals used for defoliation or growth control in crops, 1982 (acres) U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99 unspecified unspecified PCT0807 Percent of county treated for defoliation or growth control in crops, 1982 U.S. Department of Commerce, 1989a numeric values greater than 0, missing = -99.000 unspecified unspecified FIPSST two-digit state FIPS code Federal Information Processing Standard 01 - 56, none = 0 unspecified unspecified FIPSCNTY three-digit county FIPS code Federal Information Processing Standard 001 - 998, missing = 0 unspecified unspecified AG_CHEM.AAT Line attribute table ARC/INFO file FNODE# Internal number of from-node Computed Sequential unique positive integer unspecified unspecified TNODE# Internal number of to-node Computed Sequential unique positive integer unspecified unspecified LPOLY# Internal number of polygon to left of arc Computed Sequential unique positive integer unspecified unspecified RPOLY# Internal number of polygon to right of arc Computed Sequential unique positive integer unspecified unspecified LENGTH Length of arc in coverage units (meters) Computed Positive real numbers unspecified unspecified AG_CHEM# Internal feature number Computed Sequential unique positive integer unspecified unspecified AG_CHEM-ID User-assigned feature number User-defined Integer unspecified unspecified BNDTYPE boundary type see narrative 0-8 unspecified unspecified CENSUS ATTRIBUTES All census attributes were extracted from tabular data files provided by the U.S. Department of Commerce (1989a). Data are reported in either thousands of dollars, number, acres, or percent of county. Attribute names are keyed to field names found in the technical documentation of the the Census of Agriculture (U.S. Department of Commerce, 1989b). Specifically, the four-digit number at the end of the ARC/INFO item name matches the field-name numbers in the technical-documentation reference. Complete definitions of attributes and terms used in the census can be found in U.S. Department of Commerce (1989b; 1990). Thirty-three attributes from the 1987 Census of Agriculture were added to an ARC/INFO coverage of agricultural-chemical use estimates. The coverage name, attribute names, and short attribute descriptions are listed in table 1. Attribute names beginning with CA represent data fields transferred directly from the census tabular data files. Attribute names beginning with PCT are percent-of-county attributes, and represent relative intensities of an agricultural practice. Attributes reported as percent of county were calculated as the attribute value (in acres) divided by the county polygon area (in acres) multiplied by 100. Table 1. 1987 Census of Agriculture agricultural-chemical use estimates coverage name, attribute names, and short attribute descriptions ___________________________________________________________________________ AG_CHEM--Coverage of agricultural-chemical use estimates from the 1987 Census of Agriculture ___________________________________________________________________________ Attribute name Description ___________________________________________________________________________ CA0772 Commercial fertilizer, 1987 (acres on which used) PCT0772 Percent of county treated with commercial fertilizer, 1987 CA0773 Commercial fertilizer, 1982 (acres on which used) PCT0773 Percent of county treated with commercial fertilizer, 1982 CA0776 Cropland fertilized, 1987 (acres on which used) PCT0776 Percent of county as cropland fertilized, 1987 CA0777 Cropland fertilized, 1982 (acres on which used) PCT0777 Percent of county as cropland fertilized, 1982 CA0780 Pastureland and rangeland fertilized, 1987 (acres on which used) PCT0780 Percent of county as pastureland and rangeland fertilized, 1987 CA0784 Lime, 1987 (acres on which used) PCT078 Percent of county treated with lime, 1987 CA0786 Lime, 1987 (tons) Sprays, dusts, granules, fumigants, and other compounds use to control -- CA0790 Insects on hay and other crops, 1987 (acres on which used) PCT0790 Percent of county treated for insects on hay and other crops, 1987 CA0791 Insects on hay and other crops, 1982 (acres on which used) PCT0791 Percent of county treated for insects on hay and other crops, 1982 CA0794 Nematodes in crops, 1987 (acres on which used) PCT0794 Percent of county treated for nematodes in crops, 1987 CA0795 Nematodes in crops, 1982 (acres on which used) PCT0795 Percent of county treated for nematodes in crops, 1982 CA0798 Diseases in crops and orchards, 1987 (acres on which used) PCT0798 Percent of county treated for diseases in crops and orchards, 1987 CA0799 Diseases in crops and orchards, 1982 (acres on which used) PCT0799 Percent of county treated for diseases in crops and orchards, 1982 CA0802 Weeds, grass, or brush in crops and pasture, 1987 (acres on which used) PCT0802 Percent of county treated for weeds, grass, or brush in crops and pasture, 1987 CA0803 Weeds, grass, or brush in crops and pasture, 1982 (acres on which used) PCT0803 Percent of county treated for weeds, grass, or brush in crops and pasture, 1982 CA0806 Chemicals used for defoliation or for growth control of crops or thinning of fruit, 1987 (acres on which use PCT0806 Percent of county treated with chemicals used for defoliation or for growth control of crops or thinning of fruit, 1987 CA0807 Chemicals used for defoliation or for growth control of crops or thinning of fruit, 1982 (acres on which use PCT0807 Percent of county treated with chemicals used for defoliation or for growth control of crops or thinning of fruit, 1982 _________________________________________________________________________ Census estimates for counties represented by one polygon are equal to county totals. For counties described by more than one polygon, attribute values are provided for each polygon and are calculated as the county total multiplied by the ratio of the area of each county polygon divided by the total area of the county. A missing-value code of -99 is used when no census-attribute data are given for a county, and for all nonland-area polygons. A missing-value code in a county land polygon could indicate any of the following condition: --agricultural practice not present in county (for example, no corn grown in county) --data withheld because of census disclosure rules --data not available to census --data not published because county contains less than 10 farms --data not applicable COUNTY POLYGON ATTRIBUTES Each county is identified by a five-digit Federal Information Processing Standard (FIPS) code. The first two digits represent the state and the three remaining represent the county within State. County names (in upper case) and the two-character State abbreviation also are included. All polygons are coded by polygon type (PLYTYPE) as follows: 0 = U.S. land. 1 = Extensions of counties into the ocean and estuaries. Some boundaries may be arbitrary. 2 = U.S. Great Lakes. Some boundaries between counties may be arbitrary. 3 = Canadian Great Lakes. 4 = Canadian islands in Great Lakes, included for visual cartographic purposes. 9 = External polygon. All arcs are coded by boundary type (BNDTYPE) as follows: 0 = Coastline of 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, an estuary, or a Great Lake. Some of these borders are arbitrary. 4 = County-county border, with State, but occurring on the ocean, an estuary, or a Great Lake. Some of these borders are arbitrary. 5 = International border occurring on land. 6 = International border occurring on water. 7 = Canadian shoreline of the Great Lakes. 8 = Arbitrary separation line between the Canadian portions of the Great Lakes. 9 = Closure line with the external polygon. This is arbitrary. All BNDTYPE values are determined from the adjoining polygons by the routine, INDEX_COUNTY.AML. The coverage is indexed (ARC: INDEXITEM) on FIPS code, State FIPS code, State abbreviation, county name, polygon type, and boundary type. Not Available U.S. Geological Survey Ask USGS - Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Export Full coverage zipped 3.73 MB http://water.usgs.gov/GIS/dsdl/ag_chem.e00.gz Export Full coverage winzip 3.87 MB http://water.usgs.gov/GIS/dsdl/ag_chem.e00.zip SDTS Full coverage winzip 3.02 MB http://water.usgs.gov/GIS/dsdl/ag_chem.sdts.zip SDTS Full coverage zipped 2.93 MB http://water.usgs.gov/GIS/dsdl/ag_chem.sdts.tgz None. This dataset is provided by USGS as a public service. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+ag_chem FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998