The Voronoi diagram is closely related to gravity models:
every cell in the raster map gravitates towards the closest center
point in the input point pattern.
If you change the gravitational attraction of individual points,
you get a weighted Voronoi diagram. If you change the measure
of gravity
Hamish wrote:
- use r.param.scale to create a feature map and extract all saddle-point
boundaries between the bubbles as the voronoi boundaries,
(or r.slope.aspect and find areas where slope1 deg then r.thin, r.to.vect)
Wouldn't this work with cost surfaces too? Starting from several
Interesting. I know something of these models (worked a few years for
the archaeology department here in Amsterdam), and, like you, never had
enough time to really code it. Apart from efficiency, I am wondering
whether those really cool cost surfaces will degenerate into impossible
vector
Jan wrote:
Wouldn't this work with cost surfaces too? Starting
from several points (the Thiessen centers) with a grid cell
cost information raster containing only the value
one, you get a raster representation of a
classic Thiessen structure. Manipulating the cost
information raster , you
Jan Hartmann wrote:
With that in mind, if the algorithm you propose would be indeed an
approximation to weighted Voronoi polygons, *and* it wouldn't be
all to hard to implement (I have no idea about that), would it make
sense to propose this as a new RFC for GRASS?
Glynn wrote:
I
Glynn Clements wrote:
Jan Hartmann wrote:
With that in mind, if the algorithm you propose would be indeed an
approximation to weighted Voronoi polygons, *and* it wouldn't be all to
hard to implement (I have no idea about that), would it make sense to
propose this as a new RFC for GRASS?
Jan Hartmann wrote:
With that in mind, if the algorithm you propose would be indeed an
approximation to weighted Voronoi polygons, *and* it wouldn't be all to
hard to implement (I have no idea about that), would it make sense to
propose this as a new RFC for GRASS?
Oops; I
Jan Hartmann wrote:
With that in mind, if the algorithm you propose would be indeed an
approximation to weighted Voronoi polygons, *and* it wouldn't be all to
hard to implement (I have no idea about that), would it make sense to
propose this as a new RFC for GRASS?
Oops; I spoke too
Milton Cezar Ribeiro wrote:
Is there a command r.grow.distance on GRASS?
I tryed to find it on Native WinGrass, but it appears not be available,
almost on 6.3 version.
It's new in 6.4/7.0.
--
Glynn Clements gl...@gclements.plus.com
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grass-user
Jan Hartmann wrote:
The problem with using r.cost is that you would need to know the cost
for each cell before you have created the polygons.
I think that the simplest accurate approach would be to modify
r.grow.distance.
Do you mean: adding a metric parameter to Euclidean, Squared,
Yes, I guess that what I meant too, you just formulate it better, in a
more general way. I find this interesting, as I have experimented with
weighted Voronoi polygons, but only in vector format. There is a
complete book on that methodolgy: Atsuyuki Okabe, Barry Boots, Kokochi
Sugihara, Sung
Glynn Clements wrote:
Dylan Beaudette wrote:
While we are on this topic, is there a way to get a weigthed voronoi
diagram using grass ?
The ability to rank a point to tune the area's influence would be great,
for that purpose I've been using an arcgis'extension* but with grass it
is not
Moritz Lennert a écrit :
On 12/02/09 04:15, Dylan Beaudette wrote:
On Wed, Feb 11, 2009 at 5:03 PM, Dylan Beaudette
debeaude...@ucdavis.edu wrote:
On Wednesday 11 February 2009, MORREALE Jean Roc wrote:
Hamish a écrit :
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in
The messages from Kurt Spring and Jean Roc Morreale point to
archaeological work using GRASS. How many other archaeologists are
there on the list using GRASS. I'd be interested in hearing about
archaeological applications as I have just begun the learning curve
for my own archaeological
Lyle E. Browning wrote:
The messages from Kurt Spring and Jean Roc Morreale point to
archaeological work using GRASS. How many other
archaeologists are there on the list using GRASS.
I believe quite a few,
I'd be interested in hearing about archaeological applications as I
have just begun
Hamish a écrit :
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
sites that are in point vector files.
v.voronoi
there is some replacement test code to look at in grass-addons as well:
On Wednesday 11 February 2009, MORREALE Jean Roc wrote:
Hamish a écrit :
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
sites that are in point vector files.
v.voronoi
there is some
On Wed, Feb 11, 2009 at 5:03 PM, Dylan Beaudette
debeaude...@ucdavis.edu wrote:
On Wednesday 11 February 2009, MORREALE Jean Roc wrote:
Hamish a écrit :
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
Dylan Beaudette wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
sites that are in point vector files.
v.voronoi
there is some replacement test code to look at in grass-addons as well:
Hi folks,
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb sites that
are in point vector files.
Thanks for any help you can give.
Kurt
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Try
v.surf.idw
Cheers
Harald
Kurt Springs wrote:
Hi folks,
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb sites that
are in point vector files.
Thanks for any help you can give.
Kurt
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
sites that are in point vector files.
v.voronoi
there is some replacement test code to look at in grass-addons as well:
That did the trick.
Thanks Hamish
Kurt
On Feb 10, 2009, at 6:47 PM, Hamish wrote:
Kurt Springs wrote:
Does anyone know how to do Thiessen Polygons in GRASS?
I need to use them around various types of megalithic tomb
sites that are in point vector files.
v.voronoi
there is some
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