Nebraska Topographic Maps (Digital Raster Graphics)

Introduction

Since April, 1979,we have maintained a formal agreement with the U.S. Geological Survey (USGS) designating the School of Natural Resources (SNR) as the USGS Earth Science Information Center (ESIC) for the state of Nebraska. ESIC serves as a clearinghouse for topographic, vegetation, soils and geological maps, historical and contemporary aerial photography and satellite imagery, soil surveys, National Wetlands Inventory data and many other types of digital cartographic data. Copies of all Nebraska topographic maps are stocked and sold to the public. Nebraska Maps and More, the SNR store, is pleased to serve as the outlet for Digital Raster Graphics, a revolutionary new map series recently completed for Nebraska.

What is a Digital Raster Graphic (DRG)?

A digital raster graphic (DRG) is a scanned image of a USGS standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch. The USGS is producing DRGs of the 1:250,000, 1:100,000, and 1:24,000-scale.