Computes an histogram of an NDF’s values
Computes an histogram of an NDF’s values
By default, each data value contributes a value of one to the corresponding histogram bin, but alternative weights may be supplied via Parameter WEIGHTS.
TRUEif labelled and annotated axes are to be drawn around the plot. The width of the margins left for the annotation may be controlled using Parameter MARGIN. The appearance of the axes (colours, founts, etc.) can be controlled using the Parameter STYLE. The dynamic default is
TRUEif CLEAR is
TRUEthe current picture is cleared before the plot is drawn. If CLEAR is
FALSEnot only is the existing plot retained, but also an attempt is made to align the new picture with the existing picture. Thus you can generate a composite plot within a single set of axes, say using different colours or modes to distinguish data from different datasets.
"Error"is the alternative to
"Variance"and causes the square root of the variance values to be taken before computing the statistics). If
"Quality"is specified, then the quality values are treated as numerical values (in the range 0 to 255).
TRUEthen a cumulative histogram is reported.
!), no plot will be made.
[Current graphics device
!) value is supplied, the value used is
0.15(for all edges) if either annotated axes or a key are produced, and zero otherwise.
!) is entered the histogram NDF is not created.
lower,upper –- You can supply explicit lower and upper limiting values. For example,
"10,200" would set the histogram lower limit to 10 and its upper limit to 200. No
method name prefixes the two values. If only one value is supplied, the
is adopted. The limits must be within the dynamic range for the data type of the NDF
"Percentiles" –- The default values for the histogram data range are set to the
specified percentiles of the data. For instance, if the value
supplied, then the lowest 10% and highest 1% of the data values are excluded
from the histogram. If only one value, p1, is supplied, the second value,
defaults to (100 - p1). If no values are supplied, the values default to
must be in the range 0 to 100.
"Range" –- The minimum and maximum array values are used. No other sub-strings are
needed by this option. Null (
!) is a synonym for the
"Sigmas" –- The histogram limiting values are set to the specified numbers of standard
deviations below and above the mean of the data. For instance, if the supplied value is
"sig,1.5,3.0", then the histogram extends from the mean of the data minus 1.5 standard
deviations to the mean plus 3 standard deviations. If only one value is supplied, the
second value defaults to the supplied value. If no values are supplied, both default to
"Sigmas" methods are useful to generate a first pass at the
histogram. They reduce the likelihood that all but a small number of values lie within
a few histogram bins.
The extreme values are reported unless Parameter RANGE is specified on the command line. In this case extreme values are only calculated where necessary for the chosen method.
The method name can be abbreviated to a single character, and is case insensitive. The
initial value is
"Range". The suggested defaults are the current values, or
! if these
do not exist.
A comma-separated list of strings should be given in which each string is either an
attribute setting, or the name of a text file preceded by an up-arrow character
Such text files should contain further comma-separated lists which will be read and
interpreted in the same manner. Attribute settings are applied in the order in which
they occur within the list, with later settings overriding any earlier settings given
for the same attribute.
Each individual attribute setting should be of the form:
is the name of a plotting attribute, and
is the value to assign to the attribute. Default values will be used for any
unspecified attributes. All attributes will be defaulted if a null value (
initial default–-is supplied. To apply changes of style to only the current invocation,
begin these attributes with a plus sign. A mixture of persistent and temporary style
changes is achieved by listing all the persistent attributes followed by a plus sign
then the list of temporary attributes.
See Section E for a description of the available attributes. Any unrecognised attributes are ignored (no error is reported).
The appearance of the histogram curve is controlled by the attributes Colour(Curves),
Width(Curves), etc. (The synonym Line may be used in place of Curves.)
["KAPPA - Histogram"]
!) is supplied for WEIGHTS, all input values contribute a count of one to the corresponding histogram bin. If an NDF is supplied, the histogram count for a particular input pixel is formed by dividing its weight value (supplied in the WEIGHTS NDF) by the value of Parameter WEIGHTSTEP, and then taking the nearest integer. Input pixels with bad or zero weights are excluded from the histogram.
!), the data range and Parameter NUMBIN are used to specify the bin width.
!) value is supplied, the minimum data value in the histogram is used. The value supplied may be greater than or less than the value supplied for XRIGHT.
TRUEif the plot x axis is to be logarithmic. Any histogram bins which have negative or zero central data values are omitted from the plot.
!) value is supplied, the maximum data value in the histogram is used. The value supplied may be greater than or less than the value supplied for XLEFT.
!) value is supplied, the lowest count the histogram is used. The value supplied may be greater than or less than the value supplied for YTOP.
TRUEif the plot y axis is to be logarithmic. Empty bins are removed from the plot if the y axis is logarithmic.
!) value is supplied, the largest count in the histogram is used. The value supplied may be greater than or less than the value supplied for YBOT.
style.datcontrol the style of the resulting graph. The plotting style specified in file
style.datbecomes the default plotting style for future invocations of HISTOGRAM.
style.datdoes not become the default style for future invocations of HISTOGRAM.
hist.dat. The histogram uses the current number of bins, and includes data values between the 10 and 90 percentiles. A plot appears on the current graphics device.
This routine correctly processes the AXIS, DATA, VARIANCE, QUALITY, LABEL, TITLE, UNITS, and HISTORY components of the input NDF.
Processing of bad pixels and automatic quality masking are supported.
All non-complex numeric data types can be handled.
Any number of NDF dimensions is supported.