Using a GPS with AditSite

AditTrec

You can now get hold of a program that runs on Palm OS® handheld computers, and Pocket PCs (pocket or mobile OS) that can be fully integrated with AditSite. More information on AditTrec

Our first foray into a direct interface to a GPS device started when we were contacted by an existing customer, who had bought a handheld GPS, and was using it for species recording. He recorded each species as a new waypoint, and wondered if it was possible to upload this information to his PC via a serial cable, to save lots of typing.

Now, this has two elements that are just our kind of thing:

It saves re-entering data – which isn't always a fascinating as it might be and can also be subject to transcription errors.

There was some doubt as to feasibility. If you really want to get an adit programmer to do something, you tell him that you have been reliably informed that it is not possible. Failing that, asking if it is possible with some doubt in your voice, works fairly well.

We had already developed a basic module for communicating with GPS devices using the NMEA standard (in collaboration with Alphabet Soup who develop software for Mountain Rescue groups), and could reliably read current position, altitude, etc, but to access waypoints, we needed to look more closely at the manufacturer’s own communications protocol.

The box in question was a Garmin GPS 12. Garmin have a proprietary protocol which is fairly well documented (definition available on the web), and within a day or two we were able to develop a small Garmin-specific module.

Waypoints have a maximum of six characters, and while this was sufficient for the user to distinguish between various species, it created a minor problem in terms of automatic data loading. For most species the short search string could be used, and where this was not unique, the user was simply prompted to select from the alternatives.

The picture shows the standard data input screen, with the uploaded waypoints.

Now, what else could we usefully get from the GPS?

Most modern handheld GPS systems automatically record changes in current position as a ‘track’. The usefulness of the track obviously depends on where you have been, but if for instance, you walked around the boundary of a reserve or study area, the track would be the boundary. Upload the track to AditMap – instant boundary map.

What about sending information the other way?

You have responsibility for monitoring a large number of bat boxes and badger sets. Some are fairly easy to find, but others are deep in woodland. You regularly wander about trying to find specific locations – sometimes completely in vain. Possible solution – download the position of the sites to the GPS, and use the GOTO function on the GPS to guide you to the right spot.

AditSite now has full support for the NMEA protocol and can be interfaced to all devices compatible with Garmin or Magellan devices. (which covers most operational devices). If all else fails there is a semi-automated facility for entering lat/long or UTM positions read from an, as yet, unsupported GPS.

Since the demise of the Russian GLONASS system then only the USA's GPS service has been available. However on Tuesday 27th May 2003 the European Space Agency (ESA) said in a statement that an agreement had been reached among its member states which finalised the conditions for the launch of the Galileo system of 30 satellites that will rival the USA's GPS service. The new system will come into operation in 2008 - you can be sure that AditMap will support the new service as soon as it comes into operation.