The GPS

• Vender information
  Here are links to Magellan and to information on Magellan's consumer GPS products. Our current model is the GPS 315. However, the specific models available will likely change too quickly to recommend a specific model.

• Serial Interface Hardware
  The GPS 315 accepts a serial interface cable with a "9 pin D" connector. This allows connection to the standard serial port on most PC's.

• Serial Transfer Protocol
  Magellan currently provides a PDF document describing the data transfer protocol. Follow the link Product Support and then select the links On-line Manuals and then Transfer Protocol for more information.

The "gpsutil" Software

• That Linux thing
  The software for this project runs on Linux based computers, because this is my preference. Of course, someone could do the same work with Windows based computers. If that is your bent, good luck.

• Original Source
  The original source for the GPS communication software is Brian Hennings' program gpsutil.

• Modified Source
  Never one to leave well enough along, I have been attempting to improve the transfer rate in the Linux version. So I am bound by GPL to provide my modified source.

• Data Format
  The output of the gsputil contains "whitespace" separated fields for the land mark name, latitude, longitude, and elevation. The remainder of the line contains a description or comment and a letter indicating the icon displayed on the GPS trace display. For my uses I am treating the description/icon as an unstructured character string beginning with an option key word ( start, junction, label, mark ). If this string is empty or contains just the default icon label, the data is assumed to be a point along a continuous trace. Here is a sample data set:
  

                #NAME  LATITUDE  LONGITUDE  ALTITUDE Description         Icon
                # Forest Service Rd 80
                # 05 Jun 01
                LMK050 3902.534N 07922.964W 0001182M start
                LMK051 3902.489N 07923.005W 0001259M                      a
                LMK052 3902.434N 07923.018W 0001254M                      a
                LMK053 3902.331N 07923.034W 0001235M                      a
                LMK054 3902.306N 07923.045W 0001229M                      a
                LMK055 3902.281N 07923.020W 0001225M                      a
                LMK056 3902.251N 07923.015W 0001223M                      a
                LMK057 3902.235N 07923.011W 0001223M junction
  	      

• Longitude/Latitude Values
  The longitude and latitude are giving in the compress form: ddmm.fff where
  dd = the 2 or 3 digit degrees
  mm = the 2 digit arc minutes
  fff = the 3 digit fractions of arc minutes.