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Digital Line Graphs (DLGs)

   

    Large-scale (7.5-minute) DLG Boundary,
    Hydrography and Transportation layers
    Dancyville, TN)

Digital Line Graphs (DLGs) are digital vector representations of cartographic information derived from USGS maps and related sources.

The USGS produces two primary types of DLG data:

Large-Scale (7.5-minute) DLGs correspond to the USGS 1:20,000-, 1:24,000-, and 1:25,000-scale topographic quadrangle maps. They are primarily cast to the Universal Transverse Mercator (UTM) projection system, but some are cast to the State Plane coordinate system. They are referenced to either the North American Datum (NAD) of 1927 (NAD27) or the NAD of 1983 (NAD83).

Intermediate-Scale (1:100,000-scale) DLGs are derived from USGS 30- by 60-minute quadrangle maps and are sold in 30- by 30-minute units that correspond to the east or west half of the topographic quadrangle maps. Each 30-minute unit is produced and distributed as four 15- by 15-minute cells. They are cast to the UTM projection system and are referenced to either NAD27 or NAD83.

Depending on scale, the following layers (or categories of feature type) are available:

Layer Feature Type
Public Land Survey System (PLSS) Township, range, and section lines
Boundaries (BD) State, county, city, and other national and State lands such as forests and parks
Transportation (TR) Roads and trails, railroads, pipelines, and transmission lines
Hydrography (HY) Flowing water, standing water, and wetlands
Hypsography (HP) Contours and supplementary spot elevations
Non-vegetative features (NV) Glacial moraine, lava, sand, and gravel
Survey control and markers (SM) Horizontal and vertical monuments (third order or better)
Man-made features (MS) Cultural features, such as buildings, not collected in other data categories
Vegetative surface cover (SC) Woods, scrub, orchards, and vineyards

Additional Information:

Data Use and Citation Policies

For information on how to cite USGS data plus guidance on usage restrictions,
please see our Data Citations and Use page at https://lta.cr.usgs.gov/citation.

Contact Information for User Assistance

Long Term Archive User Services
U.S. Geological Survey (USGS)
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
Sioux Falls, SD 57198-0001

Phone Number: 605-594-6151
Toll Free: 800-252-4547
Fax: 605-594-6589

Email:lta@usgs.gov
Web: https://lta.cr.usgs.gov

Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., Central Time