.help imgets Jan85 images.imutil
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NAME
imgets -- get the value of an image header parameter as a string
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USAGE
imgets image param
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PARAMETERS
.ls image
Name of the image to be accessed.
.le
.ls param
Name of the parameter whose value is to be returned.
.le
.ls value = ""
The value of the parameter, returned as a string.
.le
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DESCRIPTION
The value of the parameter \fIparam\fR of the image \fIimage\fR is returned
as a string in the output parameter \fIvalue\fR.  The CL type coercion
functions \fIint\fR and \fIreal\fR may be used to decode the returned
value as an integer or floating point value.  Both standard image header
parameters and special application or instrument dependent parameters may be
accessed.  If the parameter cannot be found a warning message is printed and
the value "0" is returned.  Parameter names are case sensitive.

The following standard image header parameters may be accessed with
\fBimgets\fR:

.nf
	i_pixtype			pixel type (short, real, etc.)
	i_naxis				number of dimensions
	i_naxis[1-7]			length of the axes (x=1,y=2)
	i_minpixval			minimum pixel value or INDEF
	i_maxpixval			maximum pixel value or INDEF
	i_title				image title string
	i_pixfile			pixel storage file name
.fi

This task is most useful for image parameter access from within CL scripts.
The task \fBimheader\fR is more useful for just looking at the image header
parameters.
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EXAMPLES
1. Fetch the instrument parameter "HA" (hour angle) from the image header of
the image "nite1.1001", and compute and print the hour angle in degrees:

.ks
.nf
	cl> imgets nite1.1001 HA
	cl> = real(imgets.value) * 15.0
	42.79335
.fi
.ke

2. Print the number of pixels per line in the same image.

.ks
.nf
	cl> imgets nite1.1001 i_naxis1
	cl> = int(imgets.value)
	1024
.fi
.ke
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SEE ALSO
imheader, hedit, hselect
.endhelp
