[GRASSLIST:5101] Re: scale_in_NVIZ

H. Bowman ihatejunkyabastards at yahoo.com
Thu Nov 28 02:19:20 EST 2002

> is there a way to place scale in NVIZ monitor such as with d.scale?

In theory:

Create a vector file in whatever way you like. I find making a grass 
ascii-vector file pretty easy. (see below, first line will be 5km long..) 
use v.in.ascii to convert that into a regular grass binary vector file & 
run v.support. use d.where to figure out where you want the starting 
coordinates to be, then just type in the numbers (adding 5000 to some) to 
make the 3 or 5 lines requried to make a nice "I" shape. Making "1KM" 
might not be too hard either. Might need v.digit to clean up nodes, etc.

Would it be possible to project something like PostScript with huge page 
dimensions to a vector file / write something to export PostScript to a 
grass ascii-vector file ???

So once you've got vector graphics of what you want to display, say a 5km 
long line start up NVIZ with your map, open the surfaces panel, New, New 
Constant, some evelation for the line to 'float' at, accept, transparency, 
new constant, 255, accept;  then, Vector panel, new, load your vector 
file, accept, and click the check boxes so it displays only on the 
transparent surface. And there you go!

If you have a Lat/Lon region, you have to do some more math to figure out 
the positions, of course, but no trig as long as your scale bar runs N/S 
or E/W.

Could work.

v.in.ascii file eg:
ORGANIZATION: DIGIT DATE:   Thu Nov 28 16:04:35
DIGIT NAME:   MAP NAME:     some_line
MAP DATE:     MAP SCALE:    2400
OTHER INFO:   ZONE:         0
WEST EDGE:    2016397.7
EAST EDGE:    2205773.4
SOUTH EDGE:   5500000
NORTH EDGE:   5649712.6
L  2
  5500500.0    2016497.5    5505500.0    2016497.5   L 3
  5500574.5    2016495.2    5500570.4    2016495.4    5500566.5    

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