[HOT] open geology map

[Hazel]

Dear Sander,

I think that a moderate list of specific conventions, well-documented, 
will be needed, because the conventions already exist in geological 
mapping. For instance, we'd probably want a consistent way to tag a 
fault with the direction that it moves in.

Thank you for your advice on subtagging rock types. I've been trying to 
figure out what the specific conventions ought to be, in order to mesh 
with OSM and other common systems. Help with this is very welcome. Would 
anyone be willing to look over my draft geological ontology and tell me 
what I've done wrong before I make a set of feature proposals?

Sorry, I've managed to be very unclear. The 3-D info is for the slope of 
the geological structures, not the slope of the land they are embedded 
in. High precision isn't needed, and even within-50-degrees precision 
can be useful. This data is measured on an exposed rock surface, with a 
clinometer (a dangling weight on a calibrated circle, usually built into 
geological compasses but easy to make from cardboard and string). I 
should probably just have left the technical description out, apologies.

I think it's OK if effort is patchy. The geology in and near urban areas 
has the most humanitarian importance; no-one would have heard of the 
Mameyes landslide had it not hit a city, and 2010 saw umpteen 
zero-fatality earthquakes larger than the one that hit Haiti.

Although I think data donations could also be an important source, I do 
think getting a small crowd of geological mappers is feasible. But as 
you say, we'll have to see.

For anyone who thinks geological mapping might be fun:
http://www.agiweb.org/environment/publications/mapping/makemaps.html

Regards,
Hazel