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| Digital Line Graph (DLG) files are digital mapping representations created with points, lines, and areas of planimetric information derived from 7.5 and 15 minute scale topographic quadrangle maps (large scale); 30 by 60 minute intermediate scale maps; and 1:2 million scale (small scale) sectional National Atlas maps. |
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| | | Example USGS DLG (Digital Line Graph) file showing roads, streets, rivers, etc. |
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| DLG files are digital representations of program-quadrangle format and sectional maps. All DLG data distributed by the United States Geological Survey (USGS) are DLG-Level 3 (DLG-3), which means the data contains a full range of attribute codes, have full topological structuring, and have passed certain quality-control checks. | Back To Top |
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| Large-scale DLG files are available for the U.S. Public Land Survey, boundaries, transportation, hydrography and in some areas, hypsography. They are produced in 7.5 minute by 7.5 minute units which correspond to USGS 1:20,000, 1:24,000, 1:25,000 scale topographic quadrangle maps. The unit sizes of 1:63,360 scale Alaska quadrangles vary depending on the latitudinal location of the unit. | Back To Top |
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| Intermediate (1:100,000) DLG files that cover transportation and hydrography, are available for all States except Alaska. Intermediate scale DLG data are sold in 30 minute by 30 minute units which correspond to the east half or west half of USGS 30 by 60 minute (1:100,000) scale topographic quadrangle maps. Each 30 minute unit is produced and distributed as four 15 by 15 minute cells, except in high-density areas, where the 15 minute cells may be subdivided into four 7.5 minute cells. | Back To Top |
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| National Atlas sectionals of the United States at 1:2 million scale are available for boundaries, transportation, and hydrography. These small-scale DLG data correspond to USGS (1:2 million) scale sectional maps of the National Atlas of the United States of America and are sold in 21 units. Fifteen sections cover the conterminous United States, five cover Alaska and one covers Hawaii. These sectional DLGs are usually sold in multi-State units. However, some may cover only one State or a portion of a State. | Back To Top |
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| For retrieving and ordering dataset records using specific dataset criteria use the USGS Earth Explorer: For maps and aerial photographs of the United States use the Microsoft TerraServer website. For topographic maps of the United States use TopoZone.com. Here are some more resources for DLG Files on the internet: | Back To Top |
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