[daip] question on fluxing

[Leonia Kogan]

John,

As I understand you want to get one number that is the sum of all the pixels 
in a map that rose above a given threshold.


You can try:

1.the task IMCLP with PIXRANGE= -A HUGE NUMBER, YOUR THRESHOLD
As a result you'll have the image clipped at your threshold.

2. the task MATH to subtract the clipped image of the initial image
   You'' have the image with zero's for the fluxes less than your threshold.

3. the task IMEAN to estimate the mean value of the last image.
   Multiply the mean value by the number of the pixel and you get 
   the sum of all the pixels in the initial map that rose above a given 
   threshold.

It is quite possible that there is a more simple way to make such a simple 
operation. But I do not know it.

Leonia
   

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>From owner-daip at kochab.cv.nrao.edu Fri Sep  1 08:39 MDT 2000
Date: Fri, 1 Sep 2000 10:27:52 -0400 (EDT)
From: John Keck <jwk at astro.columbia.edu>
To: daip at cv3.cv.nrao.edu
Subject: [daip] question on fluxing
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Hello,

I'm trying to integrate the flux density in a very irregularly shaped
region of several maps.  I was looking for a task that would add the
values of all the pixels in a map that rose above a given threshold, but
was unable to find anything.

I was thinking that I could write an external program to do the job, but I
couldn't find a way to save the flux values of a map to an external file
(I'm running under Solaris).  How can I do this?

Thank you,

John Keck



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