I am now trying to get the lakes onto the map. I have a vector file.
v.line2area
d.vect.area fill=blue
Will that also work for NVIZ?
No. It will display as a border only. (at least in 5.0.2's NVIZ)
After it is a (labeled) vector area, use v.to.rast to make it a filled
raster area, then display that surface in NVIZ.
Another approach I use for coastlines is to make a new constant surface
at height=0, color it blue, set transparency to ~ 110, and draw that
surface over the elevation map. This makes a pretty good
semi-transparent sea surface. This won't work properly for lakes of
course, but maybe if you overlay a basin filled surface with r.fill.dir you
could reproduce this effect.
I tried to use this method. The problem I am running into is that
when I run v.support, it is telling me the line areas are not enclose.
I think that it means that the lines bounding the lakes have not been
closed properly. When I use the v.line2area and the d.vect.area, the
d.mon goes completely white, no trace of the maps.
Any other ideas?
I had to deal with this same problem two days ago, and won. It was messy
so I can't tell you the exact procedure, but here are some hints...
The v.support error either means a complete circuit hasn't been made or
there is a dangling line pointing inwards from the edge of the area.
You can test which it is with v.digit.
Go into the Toolbox menu and try "o" to find open lines or "i" to show
completed islands.
Use "!" to redraw the screen or Window->"C" to blank it and get rid of
any yellow lines between these, as they both highlight to yellow.
If the line isn't closed, you should see green dots for the end points.
Snap them together with Edit->"s" snap.
If you can't find a break but it still won't register as an area, you
may have a line dangling inwards off a node. Fix by zooming and
Edit->"r" in v.digit or with v.spag.
In coastline files, I often find open ends either side of a river mouth.
Snapping these shut automatically will sometimes leave dangling lines.
You'll need to label your areas once you have them to be able to display
with d.vect.area. Use v.alabel or in v.digit with Label->"a".
other things to try:
v.build.polylines type=area
v.spag thresh=xx <- this command strips dangling lines shorter than thresh
or
v.support -s thresh=xx