Organisers - you can provide GPS files for your events by using AUK’s Planner to upload them to the server. You should provide files in GPX format, which is the only format that is usable by all models of GPS and all software. Multiple files or large files can be zipped, which actually is quite a good idea even for a single file, because a zipped file will always present as a downloadable file, rather than a screenful of gobbledygook.
The ideal file, for events up to 300km, would contain a single Track of no more than 500 points, plus as a nice optional addition, Waypoints marking each control including infos. This is the ‘lowest common denominator’ that is highly informative yet compatible with the widest range of GPS equipment and software.
For events longer than 300km, it probably will be necessary to break the ‘500 points’ barrier and use several thousand maybe, but stay with the single Track and add control Waypoints. This will be acceptable to the majority of GPSs now in use, but won’t work on some older models that are still popular. Assume that the rider will be able to adapt your file to suit their equipment.
Although a simple recorded file from a previous ride or survey of the event is completely acceptable, better results are obtained by drawing the Track afresh, using software which can ‘autoroute’ along mapped roads.
If you don’t have desktop software, there are several online planners which can do a good job of creating suitable Track files, and some of them can also be used for storage and distribution. A popular planner is BikeHike but there are many others.
For a variety of reasons, files containing Routes (as opposed to Tracks and Waypoints) are not so suitable for distribution. A Track is rather like providing a highlighted map - GPS users can just have this scrolling on their handlebars, or they can use it as a template to work up Route files to their own liking. And even people who don’t use GPS get the benefit - they can view the file in any one of several online map facilities and preview the highlighted map. A Route, on the other hand, is rarely compatible with all known GPSs, so the risk is that the user may just see it as broken.
Riders - when you download event GPS files (ideally provided by the organiser, but maybe from other sources) you should always make sure the file is going to work in your GPS. First, virus-check any downloaded file. Then, know the limitations of your GPS and adapt the file if necessary. If it is a Track and has too many points, it can be split or it can be down-sampled, or both. BikeHike and GPS Visualizer are two online facilities that can make an easy job of down-sampling. If you need a Course then BikeHike or some other planners can convert your file to TCX format. If you would prefer to use a Route file it’s best to simply use the provided Track for reference and create your own.
Finally, delete all existing Tracks and Routes from your GPS and load the event files in, and use the menus to check that they show on the map and they go all the way to the finish, not stop half way. If you are committed to paperless navigation you should consider carrying a spare GPS in your luggage - just as you would lights, or inner tubes.
Tracking - GPS is not only useful for navigation, but it records your ride as well, and in some circumstances (NB - only by agreement with the Organiser) this may be useful as proof of passage. The default recording settings (on a Garmin) work well and don’t really need to be tweaked for this purpose, and only if the event is a 600km or longer, would you need to make any changes to allow for archiving the complete track log. As far as possible, always submit a 'raw' un-altered, un-tidied track log, straight from the GPS.
Organisers who anticipate receiving GPS files for checking proof of passage, should obtain and use the special software that AUK provides for this purpose. (PC and Windows only, and GPX only.) Increasingly files are being submitted in TCX format (a proprietary Garmin format used by newer models of GPS) and Organisers should know how to convert these to GPX. The online facilities mentioned above can do this.
If you are new to the intricacies of GPS, there is a wealth of further detail at http://www.aukadia.net/gps/