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The National Mapping Program The National Mapping Program publishes a variety of multipurpose maps to serve all map users. In addition to published maps, basic map data and open-file map byproducts are available. These include aerial photographs, satellite images, advanced and reproducible map materials, geodetic control data, geographic-names data, status maps, microfilm map copies, and map data in digital form. An Index to topographic and other Map Coverage and its companion Catalog of topogrphic and other Published Maps is available for each State. Maps of Minnesota published and distributed by the United States Geological Survey (USGS), Department of the Interior are listed in two USGS publications:
These publications can be obtained free by writing to:
Box 25286, Federal Center, Bldg 810 Denver, Colorado 80225
The Catalog is a companion publication to the Minnesota Index of topographic and other Map Coverage. The Catalog lists maps and map products produced under the U.S. Geological Survey's National Mapping Program. The Catgalog lists alphabetically, groupted by map type and scale, the names, dates, and prices of all available maps. The list includes published topographic maps, othophotoquads, State maps, satellite image maps, United States maps, and World maps. In addition to published maps, the Catalog lists products available from the National Cartographic Information Center including diazo-print othophotoquads and Land Use and Land Cover map products. Also shown in the Catalog is a list of map refgerence libraries located in Minnesota, and the commercial map dealers from whom maps may be purchased. The Catalog is a companion publication to the Minnesota Index of topographic and other Map Coverage. The Catalog lists maps and map products produced under the U.S. Geological Survey's National Mapping Program. Index The Index is designed to inform map users of the various map series, special maps and map byproducts produced and distributed by the U.S. Geological Survey and to assist users in selecting and purchasing maps. The index identifies quadrangle areas by map name and scale. A map is usually named after the most prominent city, town or natural landmark shown on it. Information Pamphlet The U.S. Geological Survey has available a pamphlet titled Topographic Maps, which includes symbols, to assist map users in selecting the kind and scale of map best suited to their needs. This pamphlet can be obtained without cost from Map Distribution, U.S. Geological Survey. Order USGS Maps On-line USGS maps may be ordered on-line from the USGS web site at http://edcwww.cr.usgs.gov/ Standard Series Maps Standard quadrangle maps cover systematically subdivided areas of latitude and longitude, and are published at various scales depending on the size of the area mapped. Standard quadrangle formats range from 7.5 X 7.5 minutes covering geographic areas of 49 to 71 square miles to 1 X 2 degrees covering areas of 4580 to 8669 square miles. Standard quadrangle map scales from 1:24,000 (one inch on the map represents 2000 feet on the ground) to 1:250,000 (one inch on the map represents approximately 4 miles on the ground. Other quadrangle maps are published at scales of 1:20,000 (Puerto Rico) to 1:63,360 (Alaska). Special area maps are published at scales of 1:50,000 to 1:100,000 (County, Regional, and National Park Maps), and 1:500,000 (State Base Maps). Map Series Comparison The amount of detail shown on a map is proportionate to the scale of the map; the larger the map scale, the more detail that is shown. For example, individual houses are shown on 1:24,000-scale 7.5-minute maps, whereas only landmark buildings are shown on 1:100,000-scale 30 X 60-minute maps. Comparatively, the number of maps required to cover an area of 1 degree latitude by 2 degrees longitude is:
7.5 X 15 Minute Series
15 Minute Series
30 X 60 Minute Series
1 X 2 Degree Series
U.S. Geological Survey maps are identified by name and series. In addition, a system has been initiated whereby each map is assigned a unique reference code which indicates the geographic coordinates, type, unit of measurement, and scale of map.
An example of the Map Reference Code:
46095-E1-TM-100
Longitude = 95° West Index Number = E1 Map Type = T (Topographic) Unit of Measurement = M (metric) Map Scale = 100 (1:100 000) It is a 1:100 000-scale metric topographic map. A 30 X 60 minute quadrange showing:
Index Number Index Number is based on a location of the south east corner of the map on a grid formed by a series of east-west and north-south lines drawn every 7.5 minutes apart. See the figure below:
Thus the south-east corner of the map with reference code starting with 46095-E1 is at 46° 30' North Latitude by 95° 00' West Longitude. A map in the 7.5 minute series would have a map reference code like 46095-E1-TF-024. This map (map scale 1:24 000) would cover only the area in the E1 square on the figure above. A map in the 15 minute series would have a map reference code like 46095-E1-TF-062. With a map scale of 1:62 500, this map would cover the area in E1, E2, F1 and F2. A map in the 7.5 X 15 minute series would have a map reference code like 46095-E1-TF-025. This map (map scale 1:25 000) would cover the area in square E1 and E2 on the figure above. A map in the 30 X 60 minute series would have a map reference code like 46095-E1-TM-100. With a map scale of 1:100 000, this map would cover the area in E1 through E8, F1 through F8, G1 through G8, and H1 through H8. Becker County Maps Due to its location it requires four 1:100 000 scale maps to cover all of Becker County. These are shown in bold-face in the table below. The table also shows the names of the adjoining maps. Click on the map name to see area covered.
The 7.5 minute quadrangle (map scale 1:24 000) maps requires 45 maps to cover Becker County. These maps show a great deal of detail. Map names are taken from names of communities and physical features such as lakes, mountains, etc.
Covering West Half of Becker County, MN
Covering East Half of Becker County, MN
Range, township and section numbers, as well as township names and boundaries are indicated on both the 1:100 000 and the 1:24 000 scale maps.
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