[GRASS-user] BAnk and ditch symbols in grass (or other Open Source GIS)

[Hamish]

Tim wrote:
> I am an archaeologist mainly working within woodlands and
> need to be be able to display in grass of similar GIS the
> location of woodland banks and their associated
> ditches.  There is a standard set of symbols for this

any online link to an image of what they look like?


> but is there a way of actually getting GRASS or other GIS to
> implement these.

are they point symbols or line styles?

point symbols:
  http://grass.osgeo.org/wiki/IconSymbols

line styles are more tricky, but I would not say impossible.

> If not has anyone any ideas on how to write the appropriate
> code or adapt other code to do it.  My initial thoughts
> were to digitize the location of the features to a vector
> map. 

e.g. the fish on the above wiki page was "digitized" from the
QGIS .svg symbol in Inkscape, then a little Bézier curve math
to make the x,y points,
  http://grass.osgeo.org/wiki/Symb-fish

the "classic" model for this is the CERL castle graphic for
d.graph (see d.graph/grass_logo.txt in the source code),
initially drawn on graph paper and then transfered.



> As a vector it has direction and therefore if a
> standard was adopted say for example if a ditch existed it
> was on the rhs of the vector and the dashes marking the bank
> could then be placed on the lhs.

so you mean like cliff polylines rendered by Mapnik for
OpenStreetMap:  http://wiki.openstreetmap.org/wiki/Cliff

e.g.
http://www.openstreetmap.org/?lat=-44.1026&lon=-176.5281&zoom=13&layers=M

?

see also geology/strike_triangle:
  http://grass.osgeo.org/wiki/IconSymbols#New

grass vector lines have direction, so setting them as true-left
and right bank can be easily done. (see `d.vect display=dir`)


> Eventually the information about the profile of the bank
> and ditch needs to be analyzed statistically so having the
> information within a data base makes good sense.

should be pretty easy if lines were as a vector map. a number
of tools exist for it.


regards,
Hamish