Through this page I will recount the planning process for a trip to Prince William Sound in the Summer of 97. I scanned a topo map of Prince William Sound. Today you can buy DRG maps from the USGS so scanning is a thing of the past. More on that below. The technology is not amazing in itself, but the practical results for those of us accustomed to scanning maps is an incredible savings of time and an increase in accuracy.
Computers are like that.
This has added a meaningful technology to the backcountry traveler's bag of tricks. 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. This means the new USGS maps allow me to connect my Garmin GPS to my computer and be able to read a calibrated map on my screen by using MacGPS Pro and I can move data back and forth between my GPS and my computer.