Hi, Maybe some ideas : Le 10 Feb 2011 à 05:43, Stacho Mudrak a écrit :
Hi all,
we are solving a problem of adding a basic geological observations (measurements) to therion. When measuring a planar feature (bedding or fault or others), you measure strike and dip. When measuring linear features, trend and plunge is measured. In the case of faults, also whether it is dextral or sinistral fault is determined and potentially a magnitude.
My question is, do you have some idea/wish how to integrate these into therion?
I have some experience with that as sometime I do geological/ microtectonic field work. 1) The easiest way I found to write these informations on a map and/or field book, this is to write as you wrote a T (for planes) oriented in regards to the strike. I am used to write the strike on the side of the T, and the dip at the base of the T. For linear features, I just draw a line oriented in regards to the trend, with a point at the starting af the direction. I also write trend and plunge. I attach to this email an example of what that gives. For faults, this is a plan. When they are lines on the plan, I add a line inside the T, in regards to the side of where it plunges, and I write the value of the plunge. To say if it is a normal, inverse, dextral and/or senestral fault, one idea is maybe to write a N, I, D, S, ND, NS, ID or IS just above the T. 2) Another possibiliy to show these features is to use stereographic projections (Wulf or Schmidt diagrams), as it is usually done in publications (ex : http://en.wikipedia.org/wiki/File:StereoprojectStructuralgeol.jpg) . BUT, that means that a routine should be written to produce the projections. And, for someone that is not used to work with these data, this is very hard to read/understand. Thus, I would prefer the first solution.
Do you have some experience with it?
Our first idea is to add a standard T symbol for strike and dip measurement, but there is one problem. Orientation of this symbol is not drawn, but it is measured (with compass). But its position is given by position on the map. Should these measurements be entered into a table (as centerline data are), or put as options with symbols?
I do not know if it possible, but I think that for me it would be easier to use this symbol with options, something like : for a plan/fault : -plan "Strike" "Dip" -fault "type" - line "Plunge" (with type = N or I or D or S or ND or NS or ID or IS) for a line : -line "Trend" "Plunge" From that, you build the symbol (T/line+values) and then from the Strike or the Trend, you rotate the symbol. If that helps, that's great ! Cheers, Xavier
Do you have any ideas or comments?
Best regards, S.
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-- Xavier ROBERT CIFAR Junior Fellow GEOTOP, Département des Sciences de la Terre et de l'atmosphère Université du Quebec a Montréal CP 8888, Succursale centre-ville MONTREAL, Quebec H3C 3P8 (1-514) 987-3000 poste 3592 xavier.robert01@gmail.com http://www.geotop.ca/index.php?option=com_content&task=view&id=861&Itemid=14... http://www2.cifar.ca/research/junior-academy/cifar-junior-fellows/?i=331 http://picasaweb.google.com/xavier.robert01