bottom: in, optional, type=integer, default=0
If the `SCALE` keyword is set, the image is scaled before display so that all
displayed pixels have values greater than or equal to `BOTTOM` and less than
or equal to `TOP`.
beta: in, optional, type=float, default=3.0
The beta factor in a Hyperpolic Sine stretch.
clip: in, optional, type=float, default=2
A number between 0 and 50 that indicates the percentage of pixels to clip
off either end of the image histogram before performing a linear stretch.
constant: in, optional, type=float, default=1.0
A constant value applied in a logarithmic stretch.
exclude: in, optional, type=numeric
The value to exclude in a standard deviation stretch.
exponent: in, optional, type=float, default=4.0
The logarithm exponent in a compression stretch.
gamma: in, optional, type=float, default=1.5
The gamma factor in a gamma stretch.
interpolate: in, optional, type=boolean, default=0
Set this keyword to interpolate with bilinear interpolation the display image as it
is sized to its final position in the display window. Interpolation will potentially
create image values that do not exist in the original image. The default is to do no
interpolation, so that image values to not change upon resizing. Interpolation can
result in smoother looking final images.
maxvalue: in, optional, type=varies
If this value is defined, the data is linearly scaled between `MINVALUE`
and `MAXVALUE`. `MAXVALUE` is set to `MAX`(image) by default. Setting this
keyword to a value automatically sets `SCALE` to 1. If the maximum value of the
image is greater than 255, this keyword is defined and SCALE=1.
mean: in, optional, type=float, default=0.5
The mean factor in a compression stretch.
minus_one: in, optional, type=boolean, default=0
The value of this keyword is passed along to the cgResizeImage
command. It prevents cgResizeImage from adding an extra row and
column to the resulting array, which can be a problem with
small image arrays.
minvalue: in, optional, type=varies
If this value is defined, the data is linearly scaled between MINVALUE
and `MAXVALUE`. `MINVALUE` is set to `MIN`(image) by default. Setting this
keyword to a value automatically sets SCALE=1. If the minimum value of the
image is less than 0, this keyword is defined and SCALE=1.
missing_index: in, optional, type=integer, default=255
The index of the missing color in the final byte scaled image.
missing_value: in, optional, type=integer
The number that represents the missing value in the image.
multiplier: in, optional, type=float
The multiplication factor in a standard deviation stretch. The standard deviation
is multiplied by this factor to produce the thresholds for a linear stretch.
ncolors: in, optional, type=integer, default=256
If this keyword is supplied, the `TOP` keyword is ignored and the TOP keyword
is set equal to NCOLORS-1. This keyword is provided to make cgImgScl easier
to use with the color-loading programs such as cgLOADCT::
cgLoadCT, 5, NColors=100, Bottom=100
scaled = cgImgScl(image, NColors=100, Bottom=100)
Setting this keyword to a value automatically sets SCALE=1 and STRETCH='LINEAR', if not
defined otherwise. Available only with 2D images.
negative: in, optional, type=boolean, default=0
Set this keyword if you want to display the image with a negative or reverse stretch.
scale: in, optional, type=boolean, default=0
Set this keyword to byte scale the image before display. If this keyword is not set,
the image is not scaled before display. This keyword will be set automatically by using
any of the keywords normally associated with byte scaling an image.
stretch: in, optional, type=integer/string, default=0
The type of scaling performed prior to display. May be specified as a number
or as a string (e.g, 3 or "Log"). Available only with 2D images. If Min(image)
is less than zero or Max(image) is greater than 255, then the default value for
stretch is 1.
Number Type of Stretch::
0 None No scaling whatsoever is done.
1 Linear scaled = BytScl(image, MIN=minValue, MAX=maxValue)
2 Linear 2% A histogram stretch, with a percentage of pixels clipped at both the top and bottom
3 Gamma scaled = cgGmaScl(image, MIN=minValue, MAX=maxValue, Gamma=gamma)
4 Log scaled = cgLogScl(image, MIN=minValue, MAX=maxValue, Mean=mean, Exponent=exponent)
5 Asinh scaled = cgAsinhScl(image, MIN=minValue, MAX=maxValue, Beta=beta)
6 SquareRoot A linear stretch of the square root histogram of the image values.
7 Equalization A linear stretch of the histogram equalized image histogram.
8 Gaussian A Gaussian normal function is applied to the image histogram.
9 MODIS Scaling done in the differential manner of the MODIS Rapid Response Team
and implemented in the Coyote Library routine ScaleModis.
10 StdDev Standard deviation stretch. scaled = cgSDevScl(image, MULTIPLIER=2).
11 Compression Compress mid-tones in image with cgCompressScl.
sigma: in, optional, type=float, default=1.0
The sigma scale factor in a Gaussian stretch.
top: in, optional, type=integer, default=255
If the `SCALE` keyword is set, the image is scaled before display so that all
displayed pixels have values greater than or equal to `BOTTOM` and less than
or equal to `TOP`.