On Aug 24, 2010, at 3:34 AM, [email protected] wrote: > Date: Mon, 23 Aug 2010 17:20:19 -0700 (PDT) > From: Hamish <[email protected]> > Subject: Re: [GRASS-user] BAnk and ditch symbols in grass (or other > Open Source GIS) > To: [email protected], Dr Tim Southern > <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset=iso-8859-1 > > 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 B?zier 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
I wonder if an enterprising programmer could start with the d.rast.arrow code and use it to allow different symbols than arrows? Michael _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
