[UW-GIS-L] "Smoothing" question (fwd)

[Harvey Greenberg]

Your apparently have a grid of points, not a grid grid, i.e. a raster.  
The first thing you can do to make your map look better is to alter your 
point symbol to eliminate the black border.  If tis does not satisfy 
you, convert your points to a real grid.  A grid can be smoothed with 
the focalmean function.  If the size of the grid cells is distracting, 
cut your cell size in half and do a bilinear RESAMPLE.  If you want to 
fill in the large no_data holes, there are several options, including 
EUCALLOCATION to assign a cell the value of the nearest data cell; and 
doing a large-radius FOCALMEAN and MERGEing the original grid with the 
smoothed one. 

harvey

A. Zald wrote:
> I am forwarding Alan's question about 'smoothing' methods/techniques 
> to the generous folks on this list.  Just in case Alan isn't a 
> subscriber, please be sure to respond to all copied on this message, 
> or to copy your reply to haynie at u.washington.edu
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
>
> Anne Zald
> Map Collection & Cartographic Information Services
> University of Washington Libraries
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
>
>
> ---------- Forwarded message ----------
> Date: Wed, 25 Apr 2007 15:30:59 -0700 (PDT)
> From: haynie at u.washington.edu
> To: gis at lib.washington.edu
> Subject: "Smoothing" question
>
> Hello,
>
> I'm not sure if this is the type of question that I should direct to 
> someone there, but thought I'd give it a try.  Attached is a map of a 
> grid with darkening for higher values.  I know that there are a number 
> of issues about how to spatially smooth (kriging etc), but I'm 
> interested here in just making this looks "smoohter" - so that you 
> can't see all the individual records.  Any suggestions about the 
> easiest/best way to do this?
>
> Thanks much,
> Alan
>
>
>
>
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-- 
hgreen at u.washington.edu  374 Johnson Hall 206-685-7981	
http://gis.ess.washington.edu/

	Harvey Greenberg
	University of Washington
	Department of Earth and Space Sciences
	Box 351310
	Seattle WA 98195-1310