Coming soon...

Hi Matthew. That's great to hear. (1) I definitely prefer "elevation", but it's nothing more than a preference. To me, "altitude" is more about flying (when there's no contact with the ground such as in an aeroplane) whereas "elevation" isn't. (2) That depends, I guess. It's often considered really bad practice to start a graph at anything other than zero, but for me I think the gradient detail is more important, as long as it's clear what the axes are starting and finishing on, and how much space is represented in between the extremes. In some ways, it could be quite cool to have comparison graphs, where multiple routes can be visually compared in the same set of axes (or two different sets that share the same scale).

+1 for elevation (but it’s not critical). Starting at sea level is not important– as Izogi says, clarity of gradient is more useful. Regarding scale – Matthew, (IMO) a lot of value in elevations comes from the ability to compare one with another. That’s only possible if the vertical and horizontal scales (of each elevation) are the same (or at least the same ratio V:H). That way, a slope of (say) 45deg on elevation1 is a 45deg slope on elevation2. However, I suspect you are considering an automatic scale that suits the display window. Can I make a plea for a user-specified scale as an option? Another ‘feature’ for GPX data would be to display multiple gpx tracks on the map – have a button in Nearby that displays the map and the existing GPX tracks (and DOC tracks too?)

Uhuh. In this case, I think the only value in starting at zero is to communicate the elevation above sea-level, which might be relevant when considering things like weather. That can probably be communicated elsewhere just as easily without a graph. As it's often common to start a walk from a known point of the elevation graph, though, like maybe the left-hand-end of it, I think people are most likely to be keen on seeing the up and down variations from that point onwards.

Umm, the vertical would be labeled. One doesn't need to start the vertical axis at zero to know that 700m = 700m above sea level. (I hope this line graph lines up :) 1000 | | * | * * | * * * * 700 |__*____________

Bum, it didn't. The editor strips out all the spaces. I'll try again 1000 | ........|........* ........|......*.....* ........|.....*......... * * * ..700 |__*___________*_

Thanks everybody for your input. Regarding altitude vs elevation: as I understand it, there is a very subtle technical difference in meaning. I think Elevation is more the norm, so I'll go with that. Regarding comparison charts: that's definitely something that could be possible in future. Currently, the V:H scale is constant (2:1), and this works reasonably well for a short track (less than 10km). But I'm not sure this is workable for longer tracks as the horizontal space is fixed, meaning the chart height will get smaller and smaller. As an example, a to-scale cross section of Te Araroa would be pretty much flat. Perhaps I can offer both a constant V:H scale and a dynamic scale. Displaying multiple GPX trails on the map: yes, that's coming. The primary goal of shifting data out of GPX files and into the database is to facilitate track lines on maps. Regarding DOC track data: I have looked at it, but it wasn't immediately obvious how to import it. I will come back to it. By the way, this makes a very pleasing elevation profile: tramper.co.nz/?8571 I will likely be able to upload something tomorrow for you to see. Matthew

Have a host of GIS tools here, so if you can tell me a format that suits you for DOC tracks, then it should be a fairly simple job to get the DOC shapefiles into whatever format you require.

According to Collins and Oxford dictionaries, elevation and altitude both can mean height above sea-level (although elevation does have a broader meaning). Having both constant and dynamic scale options would fit most needs, I think. I’ve used a ration of 4.5:1 for my profiles (for no more reason that it looked appropriate) – Matthew, I've tried to upload an example (a couple of times - seemed to work OK) but the jpg isn't accessible to me. The biggest limitation as you’ve described it, is a fixed horizontal space – any way to fix the vertical and calculate the horizontal from that (and have it scrollable, if needed)?

Ahh, the profile has turned up - just my lack of patience ! tramper.co.nz/?8716