[GRASSLIST:7775] "densifying" or adding vertices to breaklines

GRASS GRASS user
1

We're looking to add points from breaklines into our DEM point maps, so we can do terrain analysis. Is there a similar concept in GRASS for doing this? Perhaps this is the way to do it, let me know if you have any ideas.

Tyler

2

Hi Tyler,

You can use v.to.points to create points along your contour lines. After, you should use v.patch to combine your points layer.

Sadly, I can't explain you how to create your attribute table when you do your v.patch command. I ask a question about that this morning but I don't get an answer by now.

There is also some parameters that can be pass to v.surf.rst to deal with this.

Hope this help,

Jean-Denis

Tyler Mitchell wrote:

We're looking to add points from breaklines into our DEM point maps, so we can do terrain analysis. Is there a similar concept in GRASS for doing this? Perhaps this is the way to do it, let me know if you have any ideas.

Tyler

3

Merci JD, I now understand better what you meant. It sounds like we are after the same thing - now we just need some help! :slight_smile:

Tyler

Jean-Denis Giguere wrote:

Hi Tyler,

You can use v.to.points to create points along your contour lines. After, you should use v.patch to combine your points layer.

Sadly, I can't explain you how to create your attribute table when you do your v.patch command. I ask a question about that this morning but I don't get an answer by now.

There is also some parameters that can be pass to v.surf.rst to deal with this.

Hope this help,

Jean-Denis

Tyler Mitchell wrote:

We're looking to add points from breaklines into our DEM point maps, so we can do terrain analysis. Is there a similar concept in GRASS for doing this? Perhaps this is the way to do it, let me know if you have any ideas.

Tyler

4

Hi,

to join two vector data sets use v.append from wiki. It will join
atribute data tables too. Unfortunatly it is slow on large data sets.

http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassAddOns

Maris.

On 8/4/05, Jean-Denis Giguere <jdenisgiguere@fastmail.fm> wrote:

Hi Tyler,

You can use v.to.points to create points along your contour lines.
After, you should use v.patch to combine your points layer.

Sadly, I can't explain you how to create your attribute table when you
do your v.patch command. I ask a question about that this morning but I
don't get an answer by now.

There is also some parameters that can be pass to v.surf.rst to deal
with this.

Hope this help,

Jean-Denis

Tyler Mitchell wrote:
> We're looking to add points from breaklines into our DEM point maps, so
> we can do terrain analysis. Is there a similar concept in GRASS for
> doing this? Perhaps this is the way to do it, let me know if you have
> any ideas.
>
> Tyler
>

5

We're looking to add points from breaklines into our DEM point maps,
so we can do terrain analysis. Is there a similar concept in GRASS
for doing this? Perhaps this is the way to do it, let me know if you
have any ideas.

If I understand correctly (which is always doubtful), try (v.segment or
v.split from grass 6.1-cvs) + v.to.points -v.

Hamish
(sorry for the late reply)