smoothing contours (image.smooth)

   Hi all,
   I was wondering if anyone in here is familiar with
the command "image.smooth".
   How can set the arguments dx, dy and theta to
minimize the smoothing?

   Is there any other way to get smoother contour
maps, ie, without so many sharp corners?

   I'd appreciate any help.
   Thank you very much.

On Thu, 24 Apr 2008, F. De Sales wrote:

   Hi all,
   I was wondering if anyone in here is familiar

with

the command "image.smooth".
   How can set the arguments dx, dy and theta to
minimize the smoothing?

Read ?image.smooth in the fields package, and run
the examples with 
various values until you can see what they do, with
the alternative of 
reading the source code.

   Is there any other way to get smoother contour
maps, ie, without so many sharp corners?

The function is not adding any information, so if
there are sharp corners 
in the contours, then there are sharp corners in the
data, and smoothing 
is not your friend. One possibility is to change the
resolution of the 
image, which should remove sharp boundaries that are
only artefacts of the 
resolution - for example by interpolating to a
denser grid.

Roger

   I'd appreciate any help.
   Thank you very much.




    

[[elided Yahoo spam]]

-- 
Roger Bivand
Economic Geography Section, Department of Economics,
Norwegian School of
Economics and Business Administration, Helleveien
30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no