Digitizing in GRASS

[David D Gray]

Alejandro Imass wrote:
> 
> Hello All.
> 
> There is an option to break a line in the digitizer. But is there an
> option to eliminate a node ?
> Or, is there a function to eliminate end point nodes that are snapped?
> 
> Here is the problem in detail:
> 
> I am digitizing at a high zoom with the mouse and a backdrop image. So I
> have to stop digitizing while I pan to the section.
> After I finish I run Edit mode and snap all nodes, and label the areas.
> When I run v.support and tell it to snap nodes to a given threshold, it
> goes mad with the vector file. Because of this I would like to know if
> there is manual method of eliminating unneeded nodes that are on the
> same line.
> 
> Any suggestions?
> 
> Thanks,
> Alejandro Imass

Hi Alejandro

v.trim does this - as long as you set the threshold option to 0, then
it won't make any other changes. But you must copy the dig_att file from
the old map to the new, as v.trim doesn't (it seems) copy attributes.
It just builds an empty attribute file. Then once you've copied it,
run v.support. Voila - all excess nodes are gone!

There's also a recent module called v.build.polylines which also
is supposed to do this but I haven't been able to check it yet.
But there's no manual way of elliminating just one node while
in v.digit.

David