Hey GRASS/QGIS folks.
I have a base vector layer for a lake that I wish to digitize over.
When I use v.digit and create a new layer, my display blanks, hiding the lake layer. The VIEW does not change extents as I can display the new dumby vector over the old one after I SAVE AND EXIT. However its hard to line up a land feature to the shoreline without seeing the shoreline while digitizing.
My work around is to make a dumby vector in GRASSA and then digitize in QGIS. Which brings up a second issue. If I delete the dumby vector in QGIS before making a new one, the vector file becomes currupt for both QGIS and GRASS. So you start with one dumby vector in GRASS, create a new less obtrusive dumby vector in QGIS and delete the old dumby GRASS vector before you start digitizing. To say the least, a few extra steps that would be nice to avoid. This would be a major drawback to using GRASS/QGIS in a production digitizing scenario.
How do I use GRASS to digitize a new layer over an existing one. Do I need to provide more info to this list?
Vitals.
-----------
GRASS 6.1 CVS
QGIS 0.7 pre2
Gentoo linux 2.6 kernel
--
+---------------------------------------------------------------+
|Dave Sampson: Geographic Information System (GIS) Technician |
| |
|Centre for Sustainable Watersheds |
|Cooperative Approaches to Protect Canada's Water Resources |
| |
|14 Water St, P.O Box 280. Portland Ontario, Canada. K0G 1V0 |
|Lat: 44.700 Long: -76.19 |
|www.watersheds.ca gis@watersheds.ca |
+---------------------------------------------------------------+
Hello Dave,
On Wed, 24 Aug 2005 09:17:52 -0400 Dave Sampson <gis@watersheds.ca>
wrote:
Hey GRASS/QGIS folks.
I have a base vector layer for a lake that I wish to digitize over.
When I use v.digit and create a new layer, my display blanks, hiding
the lake layer. The VIEW does not change extents as I can display the
new dumby vector over the old one after I SAVE AND EXIT. However its
hard to line up a land feature to the shoreline without seeing the
shoreline while digitizing.
My work around is to make a dumby vector in GRASSA and then digitize
in QGIS. Which brings up a second issue. If I delete the dumby vector
in QGIS before making a new one, the vector file becomes currupt for
both QGIS and GRASS. So you start with one dumby vector in GRASS,
create a new less obtrusive dumby vector in QGIS and delete the old
dumby GRASS vector before you start digitizing. To say the least, a
few extra steps that would be nice to avoid. This would be a major
drawback to using GRASS/QGIS in a production digitizing scenario.
How do I use GRASS to digitize a new layer over an existing one. Do I
need to provide more info to this list?
To digitazie from a backdrop-map you could use the following command:
in GRASS:
d.mon x0
v.digit -n <mynewvectormap> -bgcmd='d.rast backdropmap;d.vect
oldvector'
Perhaps this is what you need?
Cheers
Stephan
--
GDF Hannover - Solutions for spatial data analysis and remote sensing
Hannover Office - Mengendamm 16d - D-30177 Hannover
Internet: www.gdf-hannover.de - Email: holl@gdf-hannover.de
Phone : ++49-(0)511.39088507 - Fax: ++49-(0)511.39088508
On 8/24/05, Dave Sampson <gis@watersheds.ca> wrote:
My work around is to make a dumby vector in GRASSA and then digitize in
QGIS. Which brings up a second issue. If I delete the dumby vector in
QGIS before making a new one, the vector file becomes currupt for both
QGIS and GRASS. So you start with one dumby vector in GRASS, create a
new less obtrusive dumby vector in QGIS and delete the old dumby GRASS
vector before you start digitizing. To say the least, a few extra steps
that would be nice to avoid. This would be a major drawback to using
GRASS/QGIS in a production digitizing scenario.
This is not clear to me. How you get a corrupted file?
Radim
Radim Blazek,
When I go into QGIS with the dumby file (say a square). If I start digitizing again (this time a circle in QGIS) then go back and delete the original feature (square) then everything is OK.
However if I delete the original feature (square) before the digitizing a new feature in QGIS (circle) then it goes CUBAR (Hard 'C' (eg K), Currupted beyond all recog).
QGIS and GRASS can't use the file anymore, even with tryinh to rebuild topography.
On 8/24/05, Dave Sampson <gis@watersheds.ca> wrote:
My work around is to make a dumby vector in GRASSA and then digitize in
QGIS. Which brings up a second issue. If I delete the dumby vector in
QGIS before making a new one, the vector file becomes currupt for both
QGIS and GRASS. So you start with one dumby vector in GRASS, create a
new less obtrusive dumby vector in QGIS and delete the old dumby GRASS
vector before you start digitizing. To say the least, a few extra steps
that would be nice to avoid. This would be a major drawback to using
GRASS/QGIS in a production digitizing scenario.
This is not clear to me. How you get a corrupted file?
Radim
--
+---------------------------------------------------------------+
|Dave Sampson: Geographic Information System (GIS) Technician |
| |
|Centre for Sustainable Watersheds |
|Cooperative Approaches to Protect Canada's Water Resources |
| |
|14 Water St, P.O Box 280. Portland Ontario, Canada. K0G 1V0 |
|Lat: 44.700 Long: -76.19 |
|www.watersheds.ca gis@watersheds.ca |
+---------------------------------------------------------------+
On 8/29/05, Dave Sampson <gis@watersheds.ca> wrote:
Radim Blazek,
When I go into QGIS with the dumby file (say a square). If I start
digitizing again (this time a circle in QGIS) then go back and delete
the original feature (square) then everything is OK.
However if I delete the original feature (square) before the digitizing
a new feature in QGIS (circle) then it goes CUBAR (Hard ‘C’ (eg K),
Currupted beyond all recog).
QGIS and GRASS can’t use the file anymore, even with tryinh to rebuild
topography.
Strange, I cannot reproduce it. The corrupted file contains feature or did you
get the problem when it was empty? What v.build prints for that map?
Radim