The Sailing Life: Navigation Software
There's a huge implication to this fact - first, all the charts that NOAA provides are free to download, and second, if you have a PC with a decent monitor and three USB or serial ports and a GPS unit you can have a full fledged navigation... I'm a big fan of open source software and I use Open Office instead of paying Microsoft huge sums of cash for a questionably useful product. OpenCPN was written specifically to do all the things a chart plotter does - run autopilots, set and follow routes, provide information about navigational items and much more. As you move from place to place the program automatically loads the chart for that area at the closest scale it can find for where you currently on. Sometimes, that takes a few seconds, but I suspect that has more to do with my computer than... It will use any NMEA GPS antenna (like, for instance Raymarine or Garmin). It will run any NMEA 0183 autopilot (like, for instance, Raymarine).