INTRODUCTION This product is the result of the first attempt by the National Agricultural Statistics Service Census Division to offer electronic map image files (on a GIF format) responding to an increasing number of requests by data users. The files offered are based on the maps shown in the 1992 Agricultural Atlas printed report. They show data only for 1992, except for those showing increase or decrease. These files graphically illustrate the Nation's agriculture by dot and multicolor pattern maps. The maps provide displays on major topics from the 1992 Census of Agriculture including number of farms, value of land and buildings, farm size, farms by value of sales, tenure and characteristics of farm operators, principal occupation of operator, and farms by type of organization. In addition, they cover land in farms and land use, irrigation, market value of agricultural products sold, farm-related income, farm production expenses, machinery and equipment, agricultural chemicals, livestock and poultry inventories and sales, crops harvested including vegetables, fruit, and nursery and greenhouse crops. Data on acreages and inventories for 1992 and 1987 are generally comparable. Dollar figures shown for expenses and agricultural product sales have not been adjusted for changes in price levels between census years. SUMMARY OF MAPPED DATA The maps in the 1992 Agricultural Atlas report show data only for 1992, except for those showing increase or decrease. The 1992 totals along with the comparable 1987 totals for each item mapped are also provided. Data on acreages and inventories for 1992 and 1987 are generally comparable. Dollar figures shown for expenses and agricultural product sales have not been adjusted for changes in price levels between census years. HOW THE MAPS WERE MADE Computer graphics techniques and technology were used in the production of the electronic version of the maps files based on the data from the 1992 and 1987 Censuses of Agriculture. The multicolored choropleth maps and the dot maps are the products of an automated statistical mapping software, and software to transform the mapping output into a electronic image format file (GIF), compatible with most of the commercially available electronic graphics browsers and computer graphics and multimedia software. The computer mapping software used the 1992 Census of Agriculture data files to create the maps from tabulations of the 1992 Census of Agriculture. The data file contained data for each county and county equivalent in the United States and its associated Federal Information Processing Standards (FIPS) code. Files containing the vector format geographic coordinates of the boundaries of each county came from the Census Bureau's county boundary file. The coordinates for each county were also identified by FIPS codes, allowing a 1-to-1 correspondence between the data and the geographic area to which they belong. The mapping software performed statistical calculations, such as classing the data into categories or dot values, and determined the symbols used to represent the data for each county. The maps for the 1992 Agricultural Atlas printed publication were developed by the U.S. Census Bureau Geography Division. CHOROPLETH MAPS A choropleth map uses a sequence of colors or shades to show the density of a phenomenon within the boundary of a geographic area. Most often, the data have been grouped into classes. To create each choropleth map file, the mapping software classed the data and prepared one overlay for the data classes per map. The map file includes an additional overlay which contained the text, the outline of the United States, and map neatline. The overlays for the classed county data were created by matching the FIPS codes of the data values with the coordinates of the appropriate county boundaries. DOT DISTRIBUTION MAPS A dot map uses a dot to represent the number of a phenomenon found within the boundaries of a geographic area. In addition, the cartographer usually attempts to show the pattern of distribution within the area by placing the dots where the phenomenon is most likely to occur. Two types of dot maps files are included in this CD-ROM: a traditional type of dot map and an increase/decrease (two color) dot map. The computer techniques for dot placement used to create the dot maps files and the ones printed in the publication are different. Therefore the number and location of dots presented by geographic area may vary slightly from those that appear on the printed report. However, both the trend shown and patterns of distribution of a phenomenon within the boundary of the geographic areas shown should be the same as those seen in the printed report. One color dots (blue) were used for each traditional dot map provided; the increase-decrease dot maps required the use of two dot colors, blue for positive values, and red for negative ones. AUTHORITY AND AREA COVERED The census of agriculture is required by law under Title 13, United States Code, sections 142(a) and 191, which directs that a census be taken in 1979, 1983, and in every fifth year after 1983 covering the prior year. The 1992 census includes each State, Puerto Rico, Guam, and the Virgin Islands of the United States. HISTORY The 1992 Census of Agriculture is the 24th taken by the U.S. Department of Commerce, Bureau of the Census. Beginning in 1997, the responsibility for conducting the Census of Agriculture has been transferred to USDA's National Agriculture Statistics Service. The first agriculture census was taken in 1840 as part of the sixth decennial census of population. From 1840 to 1950, an agriculture census was taken as part of the decennial census. A separate mid-decade census of agriculture was conducted in 1925, 1935, and 1945. From 1954 to 1974, a census of agriculture was taken for the years ending in 4 and 9. In 1976, Congress authorized the census of agriculture to be taken for 1978 and 1982 to adjust the data reference year so that it coincided with the economic censuses covering manufacturing, mining, construction, retail trade, wholesale trade, service industries, and selected transportation activities. This adjustment in timing established the agriculture census on a 5-year cycle collecting data for years ending in 2 and 7. SOURCES OF INFORMATION The data used in preparing the charts and maps shown were obtained from the 1992 Census of Agriculture. Detailed statistics for States and counties may be found in Volume 1, Geographic Area Series, of the 1992 census publications. The 1992 Census of Agriculture was conducted primarily by mail for maximum economy. Appendix A of Volume 1, Geographic Area Series, provides a more detailed description of how the 1992 census was taken. For a detailed description of coverage and data limitations, see volume 2, Part 2, Coverage Evaluation. Detailed discussions of the census report forms, the use of sampling, and estimates of sampling error are included in appendix C, volume 1. FARM DEFINITION Since 1850, when minimum criteria defining a farm for census purposes first were established, the farm definition has been changed nine times. The current definition, first used for the 1974 census, is any place from which $1,000 or more of agricultural products were produced and sold, or normally would have been sold, during the census year. The farm definition used for the outlying areas varies according to area. The report for each area includes a discussion of its farm definition. CENSUS DISCLOSURE RULES In keeping with the provisions of Title 13, United States Code, no data are published that would disclose the operations of an individual farm. However, the number of farms in a given size category or other classification, such as size of farm, is not considered a release of confidential information and is provided even though other information is withheld.