Gpx files

uisce33

Can someone help me understand how to use gpx files,basically I like to do hill walks and can't always find sat nav cords for where I want to go to but often there are gpx files to download but I'm lost as to how to use/translate it so I can use my sat nav or google maps...

BarryD

A GPX file is a common format for exporting and exchanging tracks from different GPS recording devices and software. A track in GPS terms is a series of data points (co-ords) connected by straight lines. Depending on the GPS unit or software settings, the track may be defined by a data point at each significant change in direction or maybe every 20 or 50 metres or whatever. Generally speaking, the closer the spacing of the data points, the more reliable the file, but see warning below.

People sometimes record a walk on GPS units - the unit records the track as they walk the route. ( Note that it'll record everywhere you go as long as it's switched on and set to record - so if you wander off into the bushes to take a slash, that's recorded too ) These are sometimes uploaded to websites afterwards, you could download them and then use your GPS device to follow the line. It's not a very satisfactory way of following a walk - you wouldn't want to be relying on it, more of a backup to map navigation. This is a best case scenario.

What people need to watch for are GPX files which are generated not by a GPS device on a walk, but which someone derives by tracing a line on some mapping software or satellite view. These can be complete crap - I've seen ones where the tracks go straight through dense conifer forest, across cliffs and so on.

Most GPS devices can import GPX files, check your manual or use an app like ViewRanger on smart phones etc.

blackvalley

Do you have a GPS unit and if so what make and model .

loobylou

If I import a GPX file to my GPS do I need to have a relevant base map already stored on the device?

BarryD

loobylou wrote: »

If I import a GPX file to my GPS do I need to have a relevant base map already stored on the device?

No, it should display in itself. Will look like a series of crosses or dots (the waypoints) or a line made up of various straight line segments (the track). Like attached image - this is a gpx track, the dots here are the nodes of the straight lines.

Alun

You don't even need to actually have a mapping capable GPS unit at all to import and use a GPX file. Any unit can make use of waypoints and routes for navigation whether it has mapping capabilities or not, and in fact I used an old yellow etrex just like this for years.

By the way, it should be noted that there is a distinction in GPX files between routes and tracks. Tracks are recordings of where you've been, routes are descriptions of where you want to go. The distinction can a be a bit blurred, as most GPS receivers will also allow you to follow a track, but generally speaking routes will contain far fewer points, typically as many as you'd normally put on a traditional Route Card, so say 10-20 or so, and tracks will contain several hundreds if not thousands.

loobylou

I walked the Lycian Way in Turkey last year. The maps were very poor and a lot of time was wasted in route finding. GPX files for the trail were available but I never bothered to bring my gps, I'm more a map and compass person.
I'm going back next month to walk the Carian trail. If I were to download the gpx file available to my satmap would the following be correct?
The "route" I'm to follow will appear onscreen as a series of dots on a blank background and my current position will show up too?

Alun

Yes it will. Without an underlying map though that may be difficult to interpret. I don't know the Satmap but on Garmin GPS units you can also follow a route via the compass screen. This would show you the direction of travel, distance to the next waypoint and maybe other info as well like ETA.

Also, on Garmins its possible to create custom maps. Basically if you have a map image in a common graphics format you can, with a bit of magic, create a map from it. Again I don't know if the Satmap can do this.