Oruxmaps vs avalanches

[Maki]

Hi Jose,



I'd like to propose a couple of features that would find a lot of use in the ski touring community, possibly saving lives. And I mean that literally.



First a little background is necessary. One of the necessary conditions to trigger an avalanche is a minimum slope angle. That angle varies between 25° and 30° depending on snowpack humidification, usually the higher value is taken in account. The traditional approach is to measure that angle on a paper map using contour lines, but it is time consuming and imprecise. Some Swiss maps colour slopes above 30° in red, but it is a unique case. Please note that I'm talking about degrees and not percentages for the incline, and the relevant value is the maximum angle, not the average. The average angle between the current location and the top of the slope (known as alpha angle in some circles) is useful too, to estimate the maximum distance the avalanche can cover, but that's relatively less important.



Now the feature requests:

1) Enhance the measure tool. It currently only shows the distance, but using SRTM data it could calculate elevation gain and build an elevation profile. This would require some care from the user that has to chose the line in a proper way, but I suppose this is easy to implement, and could be interesting even outside the avalanche prevention scope.

2) This is the real one. Upon user request a variation of the relief map should be calculated on the fly for the currently shown area. Colour should show slope angle rather than absolute elevation, and should be overlaid semitransparent above the map. Below 25° green, 25-30° yellow, 30-35° orange, >35° red. (35° has a special importance, but I won't go into details now)

3) Same of above, but the angle is calculated from a single position in order to evaluate the alpha angle.



I've been intentionally brief, there would be quite a bit of details to discuss for an exact implementation but I think I gave you an idea. If you are willing to work on this stuff I can go deeper and hopefully involve some real avalanche experts.



Happy holidays.

[Maki]

A French guy is already working on point 2 with a map-based approach, so I retire my proposal. I think that point 1 still has some merit if it isn't too difficult to implement.

[febs]

I am a ski mountaineer as well and boy, this idea is SUPER cool. No more guessing by crossing the ski poles!



Sent from my HUAWEI Y300-0100 using Tapatalk

[gcoue]

Hi Orux,



I'm also a ski touring guy, and all those 3 tools would be a great security increase for our sport.



Thanx for oruxmaps and Happy new year,



Guillaume

[Maki]

Well, as said a French guy is working on it.

http://www.skitour.fr/forum/read_234133.html">//http://www.skitour.fr/forum/read_234133.html

Unfortunately it turns out that DEM1 data isn't reliable enough for this kind of application. I still think that building an elevation profile as described in point 1 could be useful for general hiking too. At least having the elevation gain and possibly the average angle in addition to the horizontal distance should be easy to do.



PS: a clinometer is so much better than crossing poles... ;-)

[fblc]

Great idea.



Maybe it could be possible at least to ad a tool to calculate de ° using distance between the altititude lines.



Thanks

[bobatsar]

See http://www.openslopemap.org/">//http://www.openslopemap.org/ for mbtiles overlays which can be used in oruxmaps. I have not yet tried it but it sounds promising.