What is a DLG geography?

DLG. [data models] Acronym for digital line graph. Data files containing vector representations of cartographic information derived from USGS maps and related sources. DLGs include information from the USGS planimetric map base categories such as transportation, hydrography, contours, and public land survey boundaries.

What kinds of data are contained in the USGS DLG files?

USGS File Types DIGITAL LINE GRAPH (DLG) are vector files generated on traditional paper topographic maps. For example, this includes township & ranges, contour lines, rivers, lakes, roads, railroads and towns.

What is a DRG GIS?

DRG. [data models] Acronym for digital raster graphic. A raster image of a scanned USGS standard series topographic map, usually including the original border information, referred to as the map collar, map surround, or marginalia.

How are DLGs made?

DLGs exist at three scales: small (1:2,000,000), intermediate (1:100,000) and large (1:24,000). Large-scale DLGs are produced in tiles that correspond to the 7.5-minute topographic quadrangles from which they were derived. Layers and contents of large-scale Digital Line Graph files.

Who produces digital line graphs?

the U.S. Geological Survey (USGS)
A Digital Line Graph (DLG) is a cartographic map feature represented in digital vector form that is distributed by the U.S. Geological Survey (USGS). DLGs are collected from USGS maps and are distributed in large-, intermediate- and small-scale with up to nine different categories of features, depending on the scale.

Where can I buy digital elevation models?

5 Free Global DEM Data Sources – Digital Elevation Models

• Space Shuttle Radar Topography Mission (SRTM)
• ASTER Global Digital Elevation Model.
• JAXA’s Global ALOS 3D World.
• Light Detection and Ranging (LiDAR)
• Mars Orbiter Laser Altimeter (MOLA)

What is the collar of the map?

A digital raster graphic (DRG) is a digital image resulting from scanning a paper USGS topographic map for use on a computer. DRGs created by USGS are typically scanned at 250 dpi and saved as a TIFF. The raster image usually includes the original border information, referred to as the “map collar”.

What is digital graphing?

A Digital Line Graph (DLG) is a cartographic map feature represented in digital vector form that is distributed by the U.S. Geological Survey (USGS). DLGs are collected from USGS maps and are distributed in large-, intermediate- and small-scale with up to nine different categories of features, depending on the scale.

How do I get SRTM data?

Where can you download the SRTM data? SRTM DEM data is being housed on the USGS Earth Explorer. To download, select your area of interest. Under the data sets tab, select Digital Elevation > SRTM > SRTM 1-ArcSecond Global.