bionic (3) histogram.3NCARG.gz

NAME

       Histogram - This utility is used to generate histograms.  Histograms or bar charts are used to show the
       distribution of values in a like-sample dataset.  The individual values are sorted by size into a number
       of value ranges called class intervals.  The number of samples out of the total which fall into a class
       interval are represented as a histogram bar height.  The height of each histogram bar is proportional to
       the number of samples in that class interval.

       Various options are available including the specification of class values, spacing between histogram
       bars, shading of bars, windowing (i.e. scaling), specification of color, labels, titles, etc.  One can
       also detect and ignore missing data which has been assigned a special value.  Options are set by calls to
       routines HSTOPL, HSTOPR, HSTOPC, and HSTOPI.  A call to routine HISTGR then generates the histogram.

SYNOPSIS

       HISTGR - Generates histograms with many options available via input arguments and internal parameter
       selections.

       HSTOPC - Sets values of internal parameters of type character.

       HSTOPI - Sets values of internal parameters of type integer.

       HSTOPL - Sets values of internal parameters of type logical.  Specifically, HSTOPL is used to turn
       options "OFF", or "ON".

       HSTOPR - Sets values of internal parameters of type real.

C-BINDING SYNOPSIS

       c_histgr
       c_hstopc
       c_hstopi
       c_hstopl
       c_hstopr

ACCESS

       To use the Histogram C or Fortran routines, load the NCAR Graphics libraries ncarg, ncarg_gks, and
       ncarg_c, preferably in that order.

MESSAGES

       The possible error messages are as follows:

       HISTGR - NPTS LESS THAN 1
              The argument NPTS, number of binable values, has been entered in error.

       HISTGR - NCLASS LESS THAN 1
              NCLASS, the number of histogram bars, has been entered in error.

       HISTGR - NPTS .GT. NDIM
              The argument NPTS, number of binable values, is larger than the array dimension size.  Reduce NPTS
              or modify the code to increase the array dimension size.  Set NDIM in the code to the new array
              dimension size.

       HISTGR - NWRK .LT. NDIM+3*NCLASS+3
              The argument NWRK, the dimension size of the work array, is incorrect.  Recompute it according to
              the above formula.

       HISTGR - NCLASS .NE. NPTS (IFLAG=2)
              IFLAG = 2 signals a special case in which the input data has already been accumulated into class
              intervals.  Therefore, the number of data values, NPTS, and the number of histogram bars, NCLASS,
              must be equal.

       HISTGR - NCLASS .NE. NPTS (IFLAG=3)
              IFLAG = 3 signals a special case in which the input data has already been accumulated into class
              intervals.  Therefore, the number of data values, NPTS, and the number of histogram bars, NCLASS,
              must be equal.  (IFLAG = 3 differs from the IFLAG = 2 case only in the fact that two histograms
              are to be displayed instead of one.)

       HISTGR - NCLASS MUST EQUAL NPTS
              This is a redundant test on whether the number of input data values, NPTS, equals the number of
              bars, NCLASS, when the IFLAG option is 2 or 3.

       HISTGR - IFLAG NOT SPECIFIED OR INVALID
              HISTGR argument IFLAG is not one of the legal values of 0, 1, 2, or 3.

       HISTGR - MIN. X-VALUE .EQ. MAX. X-VALUE
              A histogram has no width.  This probably means the values of HISTGR argument CLASS have been
              entered in error.

       HISTGR - MAXIMUM Y-VALUE .EQ. 0.0
              A histogram has no data.  The histogram is plotted with a Y range of .02.  This probably means the
              HISTGR argument DAT1 had all zero values.

       HISTGR - WINDOW OPTION ERROR, RANGE IS 0. - 1.
              The internal parameter options that define the part of the frame where the histogram is to be
              drawn have been entered incorrectly.

       HSTOPC - UNDEFINED OPTION

       HSTOPI - UNDEFINED OPTION

       HSTOPL - UNDEFINED OPTION

       HSTOPR - UNDEFINED OPTION
              Either an internal parameter name or value is incorrect.  Check the spelling in the calls to
              whichever routine is cited.

       HSTOPI - LCOL MUST EQUAL 8
              The number of color indices input to HSTOPI cannot exceed 8.

       HSTOPR - INVALID SPACING PARAMETER
              Either the spacing of histogram bars, or the overlap of bars from two histograms, is outside of
              the legal range.  Valid values for spacing of bars are 0.0 (no spacing) to 4.0 (maximum spacing.)
              Valid values used to set overlap of adjacent histogram bars when comparing two datasets in one
              histogram are -4.0 (maximum overlap) to 4.0 (little or no overlap.)

SEE ALSO

       Online: histgr, histogram_params, hstopc, hstopi, hstopl, hstopr, ncarg_cbind

       Hardcopy: NCAR Graphics Fundamentals, UNIX Version

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.