[GRASSLIST:10122] Buffer and Anti Buffer

GRASS GRASS user
1

Hi,

  1. A line can grow into a polygon (area) by BUFFER

This is what we have done for a vector layer that should have contained LINES
as they wanted lines with some buffer to become POLYGONS (Areas)
They are a Geology layer consisting dolerite dykes.

  1. Now there is an order to make all Dolerite Dykes to line features, from POLYGONS…

Do we have to literally draw a median line in all these Dolerite Polygons
and make them lines…

Or Pray… is there a solution like ANTI-BUFFER…

We would be happy to send a small vector layer with our problem of

  1. Layer with buffered dolerite dykes as POLYGONS…
    to any who would like to help us with a solution.

Thanks in anticipation

Ravi

[Yahoo! Autos](http://us.rd.yahoo.com/evt=38381/ ylc=X3oDMTEzcGlrdGY5BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDMWF1dG9z/*http://autos.yahoo.com/index.html ). Looking for a sweet ride? Get pricing, reviews, & more on new and used cars.

2

Ravi, maybe you can convert to raster, then r.thin and then back to vector?

HTH

Carlos "Guano"

On 2/2/06, RAVI KUMAR <ravivundavalli@yahoo.com> wrote:

Hi,

1. A line can grow into a polygon (area) by BUFFER

This is what we have done for a vector layer that should have contained
LINES
as they wanted lines with some buffer to become POLYGONS (Areas)
They are a Geology layer consisting dolerite dykes.

2. Now there is an order to make all Dolerite Dykes to line features, from
POLYGONS..

Do we have to literally draw a median line in all these Dolerite Polygons
and make them lines..

Or Pray.. is there a solution like ANTI-BUFFER..

We would be happy to send a small vector layer with our problem of
1. Layer with buffered dolerite dykes as POLYGONS..
to any who would like to help us with a solution.

Thanks in anticipation

Ravi

________________________________
Yahoo! Autos. Looking for a sweet ride? Get pricing, reviews, & more on new
and used cars.

--
+-----------------------------------------------------------+
              Carlos Henrique Grohmann - Guano
  Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________
"Good morning, doctors. I have taken the liberty of removing Windows
95 from my hard drive."
--The winning entry in a "What were HAL's first words" contest judged
by 2001: A SPACE ODYSSEY creator Arthur C. Clarke

3

Hi,
I tried this, but reconverting to raster, make the lines shift at times.

Is there anything like Fuzzy Tolerance in GRASS (like in Arc-Info)…

Ravi

Carlos “Guâno” Grohmann carlos.grohmann@gmail.com wrote:

Ravi, maybe you can convert to raster, then r.thin and then back to vector?

HTH

Carlos “Guano”

On 2/2/06, RAVI KUMAR

[Yahoo! Autos](http://us.rd.yahoo.com/evt=38381/ ylc=X3oDMTEzcGlrdGY5BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDMWF1dG9z/*http://autos.yahoo.com/index.html ). Looking for a sweet ride? Get pricing, reviews, & more on new and used cars.