Newsgroups: info.grass.user
Path: zorro.cecer.army.mil!shapiro
From: shapiro@zorro.cecer.army.mil (Michael Shapiro)
Subject: Re: scaling imagery
Message-ID: <C800Dp.E5u@news.cecer.army.mil>
Sender: news@news.cecer.army.mil (Net.Noise owner)
Organization: US Army Corps of Engineers Construction Engineering Research Labs
References: <9305291454.AA04430@wilson>
Date: Wed, 2 Jun 1993 14:32:13 GMT
Lines: 25
In <9305291454.AA04430@wilson> kelly@crseo.ucsb.edu (Kelly Elder) writes:
In the past I have used ipw for image processing, and
before using clustering and classifying routines I have
scaled the input values from the imagery (i.e. mean=0,
std.dev=1).
I would like to use the grass routines, i.cluster and
i.maxlik for future imagery work and for classification
schemes of nonimagery data. The obvious problem is the
inability of grass to handle floating point numbers,
which means scaling by conventional methods is impossible.
Is there a statistically sound way around this problem?
thank you, kelly
GRASS will handle 32 bit integers raster maps. It treats images
as raster maps. So scale them up to large integers (provided ipw
can do this).
--
Michael Shapiro shapiro@zorro.cecer.army.mil
U.S. Army CERL (217) 373-7277
P.O. Box 9005
Champaign, Ill. 61826-9005