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Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? [message #34741]

Sat, 12 April 2003 08:25

rmoss4
Messages: 21
Registered: October 2002

Junior Member

Convert your image to integer type (or floating point, depending on
exactly what you are doing to it). Yes, it will cost you storage space.
Using band math, you could use the expression

( ( fix( b1 ) - fix( b2 ) ) gt 0 )

This will produce the expected results.

Robert Moss, PhD

xinhai68 wrote:
> Thanks all. Now I understand what happened. But, could you enlighten
> me how to solve the problem? I want to use the format of "(b1 - b2) gt
> 0" because my real expression would be much complicated and I want to
> put variables on same side.

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[Message index]

		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: rmoss4 on Sat, 12 April 2003 08:25
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: cshen on Sat, 12 April 2003 02:21
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: David Fanning on Fri, 11 April 2003 20:29
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: rmoss4 on Fri, 11 April 2003 20:02
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: rmoss4 on Fri, 11 April 2003 19:59
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: cshen on Fri, 11 April 2003 17:59
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: rmoss4 on Fri, 11 April 2003 07:10
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: cshen on Thu, 10 April 2003 22:48
		Re: ENVI band math: "b1 gt b2 " , "(b1-b2) gt 0" same or not? By: rmoss4 on Thu, 10 April 2003 19:19

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