NAME

       HSTOPR - Specifies various REAL arrays to be used by the the Histogram utility.

SYNOPSIS

       CALL HSTOPR (STRING,ARRAY,LARR)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_hstopr (char *string, float *array, int larr)

DESCRIPTION

       STRING      Character, input -- Selects an internal parameter.  The possibilities are:

                     ´WIN=ON´ or ´WIN=OFF´
                     ´SPA=ON´ or ´SPA=OFF´
                     ´MVA=ON´ or ´MVA=OFF´

                   WIN defines the portion of the frame that will receive the histogram. SPA
                   determines the spacing between histogram bars.  MVA requests a test to detect
                   input special values which denote missing data.

       ARRAY       Real, input -- It has a different use depending upon which parameter is
                   specified by argument STRING.  See the examples following argument LARR.

       LARR        Integer, input -- Dimension of ARRAY.

                   The following arrays may be defined by this routine:

                   Windowing:

                    STRING is ´WIN=ON´
                    LARR = 4
                    ARRAY(1) = XMIN
                    ARRAY(2) = XMAX
                    ARRAY(3) = YMIN
                    ARRAY(4) = YMAX

                   These coordinates define a rectangular region of the total frame in NDC´s
                   where the current histogram is to be plotted. The range of allowed values is
                   between 0. and 1. in both dimensions.

                   For example, XMIN=0., XMAX=.5, YMIN=.5, and YMAX=1.  would specify the upper
                   left quadrant of the frame.

                   IF ´WIN=OFF´, the default window for the histogram will be the entire frame.

                   Spacing:

                    STRING is ´SPA=ON´
                    LARR = 2
                    ARRAY(1) = SPAC
                    ARRAY(2) = OVERLP

                   SPAC determines the spacing of histogram bars between 0.  (no spacing) and 4.
                   (maximum spacing).  Default spacing is SPAC = 2.0.

                   OVERLP determines the overlap of adjacent histogram bars when two datasets are
                   compared.  Valid values are -4.0 (maximum overlap) to 4.0 (little or no
                   overlap).  The Default is 0.

                   When STRING = ´SPA=OFF´, there is no spacing or overlap.

                   Detecting missing values:

                    STRING is ´MVA=ON´
                    LARR = 2
                    ARRAY(1) = SETMVA
                    ARRAY(2) = SETEPS

                   SETMVA is the special value used to denote missing data.  The default value is
                   -9999.

                   SETEPS is an epsilon to use in the special value test.  If the difference
                   between a data point and SETMVA is less than SETEPS, then the data point is
                   assumed to be a missing value.  The Default is 1.E-10.

                   When STRING = ´MVA=OFF´, there is no testing for missing values.

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

USAGE

       HSTOPR is called to set parameters of type REAL before entry HISTGR is called to generate
       the histogram.  Options are the portion of the frame to receive the graphic, and the
       amount of spacing and overlap of histogram bars.

       For a complete list of parameters available in this utility, see the histogram_params man
       page.

EXAMPLES

       Use the command "ncargex thstgr" to generate a three frame example of histogram options.
       The following code defined the window and bar spacing of plot 1 on frame 3.

       C
       C  Plot 1 goes into the top left quadrant of the frame.
       C
       C       ARR7 coordinates are XMIN, XMAX, YMIN, YMAX.
       C
             ARR7(1) = 0.
             ARR7(2) = .5
             ARR7(3) = .5
             ARR7(4) = 1.
             CALL HSTOPR(´WIN=ON´,ARR7,4)
       C
             SPAC(1) = 3.0
             SPAC(2) = 0.0
             CALL HSTOPR(´SPA=ON´,SPAC,2)

       Example  "ncargex thstmv" shows three examples of histograms with missing values in the
       input data.

ACCESS

       To use HSTOPR or c_hstopr, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c,
       preferably in that order.

MESSAGES

       See the histogram man page for a description of all Histogram error messages and/or
       informational messages.

SEE ALSO

       Online: histogram, histogram_params, hstopc, hstopi, hstopl, 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.