Forum: General Topics

Hi Yano,

Are you uploading your routes by exporting them from TMJ-Mobile and then adding them to the website via the UPLOAD/Route or Track from CSV File page?

Currently the exported Route file is slightly different in format to the exported Track file and doesn't contain any altitude information. The Route file CSV format is simply each line having latitude,longtitude (or for junctions when downloading a route via the Online Routing its latitude,longitude,street_name,turn_angle).

So currently there's no way to get the altitude out of TMJ and on to the website. Also, TMJ doesn't internally store the altitude of routepoints, so this doesn't really help!!

Having said all that in principle it shouldn't be too difficult to get TMJ to also store the altitude for each routepoint, though this will only be available if you are using the Waypoint -> Add to Route functions (for Waypoints that contain altitude data), rather than simply scrolling the map and adding points at random. Would this be sufficient do you think?

It'll also need slight changes to the Route CSV format, which will probably mean that any Online Routes that have currently been saved will no longer work in the revised version (probably not a major problem though TBH).

Fortunately/hopefully I don't think I'll need to change much on the website - it *should* automatically realise that the uploaded route has altitude data, and should then display the graphs/info as with the tracks...

Any thoughts?

Cheers,
Stephen

Sorry, I missed one last sentence:

" On the website you might think of improving the Stats page with a new column "Altitude" in addition to the already available Speed, Distance and Time ... "

Actually NO stats at all are currently available for uploaded Routes, therefore all the 4 columns should be built, where Speed and Time always set to 0, of course.

As far as the Tracks are concerned, the fourth column "Altitude" would be useful. Thanks.

Cheers,
yano

Hi Stephen,

thanks for taking over the altitude stuff for the route and the export file!


" Were you looking to see, for example, total ascent/descent within each speed band? eg 'Total Ascent whilst travelling 30-40kmh', etc. "

Well, the total ascent/descent within each speed band is not really so useful for trekking purposes. Furthermore it would not be available for routes where no speed is present.
Actually I was thinking of total ascent/descent within a section of both a route and a track, or something similar (e.g. between two points) ...

Am I daring too much?! ;)

Cheers,
yano

;-) The Total Ascent/Descent per section had been there for a while - I assumed you'd already seen it!!

So anyhow, you got me thinking over the weekend and I've now added a couple of ascent/descent readings to the Stats page - figured it might have some use for others...

I also then updated the Create Route page to allow waypoint locations to be added into the route (and also taking the altitude from the waypoint). The Edit button can also now be used to set individual altitudes for each routepoint.

So then I had a look into the NASA SRTM dataset. This is a massive dataset created from a Shuttle mission to map the land height of the whole planet. I've been experimenting with their SRTM3 data, giving altitude points spaced at roughly every 90m, which seems to be pretty accurate. I've built a simple page that will update a route or track with altitudes from this dataset (its hidden away slightly at the bottom of the Track Data page). Some points to note:
- The datasets are grouped into segments for each latitude/longitude and are loaded from NASA on-demand (and then cached on the site), so the first time you use it for a particular area the page might take a while to load (just give it a minute or two).
- The altitude for a particular lat/lng is currently taken from the nearest SRTM3 point. I'll eventually make it interpolate better between the surrounding points, but it doesn't seem too bad for the moment.
- You can update all your Waypoint altitudes in one go on this page.
- The SRTM data is based on the same datum as used in GPS devices (WGS84), so the heights should roughly match a good GPS fix.
- Note that this will overwrite all existing altitudes - there is no undo function, so use with caution!!

Of course this is all fairly useless until I get the next version of TMJ-Mobile ready (which is still some way off), but it may be of some interest anyhow...

Cheers,
Stephen