Monday, 21 February 2011

New trail profiles released

Buried in our website we have a number of trail profiles that aim to give a bit more information about some of our competition venues and the courses. The maps are generally based on a combination of GPS data, topographical mapping, and satellite imagery, and the commentary is fairly described as "subjective".

Historically, we used images (screenshots) taken from a mapping product. These days, there is a wealth of choice in geographical systems, and many are based either on Google Earth or Google Maps. Because these tools are freely accessible to anyone with a PC or laptop and Internet access, it makes sense for our current approach to utilise these tools.

Therefore, we're beginning to develop map and commentary packages using both the GPX and KML/KMZ formats.

GPX is an open standard format for geographical information, particularly well suited to sports, and very portable between different mapping products. Most GPS devices will support an export function to GPX, and most mapping products will import GPX files.

KML is a proprietary format developed for Google Earth that performs essentially the same functions as GPX but with extensions and enhancements suited to the needs of 3 dimensional map viewers. KMZ is a "zipped" format of KML and is useful for distributing additional material to accompany the KML files.

In the last few days, we've added updated profiles for the Foxton and Bright's Farm venues to our pages and the KMZ and GPX files that accompany these can be downloaded from the profile pages. More detailed commentary is included in the KMZ and can be reviewed in Google Earth.

Increasingly we're able to obtain raw GPS data from the the course marking, the technical delegate inspections ("Tee-Dee-ing"), or from the ride itself (a competitor may be asked to carry a sealed GPS unit in a saddle bag). Putting it all together we get a fairly good view of the trail.

The raw data then has to be corrected and smoothed, and we tend to adjust the trail to fit with satellite imagery, which sometimes can be a little off (especially where the satellite was off to one side of a slope). There's a bit of work involved, but we think it's worthwhile, and very much in the interests of our sport to ensure that competitors have a reasonable indication of what conditions and trail features the venue offers.

At the moment we've yet to settle on a standardised presentation style, and the first attempt with Belmont looks quite different to the more recent work. And perhaps the KMZ and GPX formats aren't that convenient for you. For example, would screen shots still be useful, or would you like us to produce PDF files that you can print from?

So, take a look at what we've got, and give your feedback to a committee member. We want to make sure we're giving you useful information in a useful format.

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