DRG file extension - Digital Raster Graphics
What is drg file? How to open drg files?
File type specification:
The drg file extension is associated with the Digital Raster Graphics file format.
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 (UTM) 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.