How to join GPX files? (Read 906 times)

This isn't necessarily for Eric; it is for anyone familiar with GPX files who cares to answer.

I'd like to join two GPS tracks -- from the same run, in two segments recorded on two watches. They're not quite contiguous -- the first track covers perhaps 25mi, and the second track covers perhaps 20mi, and there is some gap between them. (But I hope that doesn't matter.)

I obtained (or will obtain) these by uploading from a watch to RA, then saving as GPX. I've only obtained one so far, actually.

It looks like this:

<?xml...>

<gpx...>

<metadata>

<time>...</time>

</metadata>

<trk>

<trkseg>

<trkpt lat="..." lon="...">

<ele>...</ele>

<time>...</time>

</trkpt>

... (lots more trkpt elements, just like the above one

</trkseg>

</trk>

</gpx>

So, each point has a latitude, a longitude, and a time (and whatever an ele is).

So my question is: how can I attach the second set to the first set?

I will produce it the same way, so I expect to get another sequence of track points (trkpt), and just need to figure out how to concatenate them to what I already have.

Should I dump another track after the first one, copying in the entire trk element? Or should I copy only the entire track segment (trkseg) element into the same track element?

What is the purpose of the metadata time element -- do I need a second at the start of the second track, if I do an entire other track?

Every point has time anyway, so I don't know really why the metadata time is very useful.

Judging by this schema, http://www.topografix.com/GPX/1/1/gpx.xsd

it appears to me that there can be multiple tracks, and a track can have multiple track segments.

I don't know what difference it would mean logically whether I record the two parts of the run as one track with two segments, or as two tracks.

Right.

Been a while since I have done this, but I have just opened in a text or XML editor and appended the trk nodes from one file to the other:

<?xml...>

<gpx...>

<metadata>

<time>...</time>

</metadata>

<trk>

<trkseg file a>

<trkpt lat="..." lon="...">

<ele>...</ele>

<time>...</time>

</trkpt>

... (lots more trkpt elements, just like the above one

</trkseg>

<trkseg file b>

<trkpt lat="..." lon="...">

<ele>...</ele>

<time>...</time>

</trkpt>

... (lots more trkpt elements, just like the above one

</trkseg>

</trk>

</gpx>

It worked. Thanks. It's funny that the laps are no longer exactly 1mi each, but that's ok.