[GRASSLIST:5613] vectors + topo

[Carlos Henrique Grohmann de Carvalho]

Hello all,
 

 
I'm trying to make a "hidraulic gradient" map for morphotectonic analysis, 
witch ahould be made by cslculating the ration between vertical and 
horizontal length of second-order stream channels and then assing this value 
to a "middle point" (in plan view) of each stream. 
 
To get a map only with selected streams segments is easy, but how to 
calculate the ratios? I was thinking on a dxf file, so I can use simple 
trigonometrics. the big problem lies in get a dxf file were the vertex of 
the lines have the "z" attribute. 
 
I tried to convert vector to raster, use r.mapcalc to get lines with z-value 
and convert it back into vector, but in the resultant file lines are all the 
same categorie.
 
Does anyone have ideas on how to make the vector vertex with the altitude 
value?
 

 
thanks in advance.
 

 
 
 

 
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   Carlos Henrique Grohmann de Carvalho - Guano   
 
    Geologist - MSc Student at IGc-USP - Brazil
 
   Linux User #89721  PGP key: www.keyserver.net
 
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