1Histogram(3NCARG) NCAR GRAPHICS Histogram(3NCARG)
2
6 Histogram - This utility is used to generate histograms. Histograms or
7 bar charts are used to show the distribution of values in a like-sample
8 dataset. The individual values are sorted by size into a number of
9 value ranges called class intervals. The number of samples out of the
10 total which fall into a class interval are represented as a histogram
11 bar height. The height of each histogram bar is proportional to the
12 number of samples in that class interval.
13 Various options are available including the specification of class
15 values, spacing between histogram bars, shading of bars, windowing
16 (i.e. scaling), specification of color, labels, titles, etc. One can
17 also detect and ignore missing data which has been assigned a special
18 value. Options are set by calls to routines HSTOPL, HSTOPR, HSTOPC,
19 and HSTOPI. A call to routine HISTGR then generates the histogram.
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22 HISTGR - Generates histograms with many options available via input
23 arguments and internal parameter selections.
24 HSTOPC - Sets values of internal parameters of type character.
26 HSTOPI - Sets values of internal parameters of type integer.
28 HSTOPL - Sets values of internal parameters of type logical.
30 Specifically, HSTOPL is used to turn options "OFF", or "ON".
31 HSTOPR - Sets values of internal parameters of type real.
33
35 c_histgr
36 c_hstopc
37 c_hstopi
38 c_hstopl
39 c_hstopr
40
42 To use the Histogram C or Fortran routines, load the NCAR Graphics
43 libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
44
46 The possible error messages are as follows:
47 HISTGR - NPTS LESS THAN 1
49 The argument NPTS, number of binable values, has been entered in
50 error.
51 HISTGR - NCLASS LESS THAN 1
53 NCLASS, the number of histogram bars, has been entered in error.
54 HISTGR - NPTS .GT. NDIM
56 The argument NPTS, number of binable values, is larger than the
57 array dimension size. Reduce NPTS or modify the code to
58 increase the array dimension size. Set NDIM in the code to the
59 new array dimension size.
60 HISTGR - NWRK .LT. NDIM+3*NCLASS+3
62 The argument NWRK, the dimension size of the work array, is
63 incorrect. Recompute it according to the above formula.
64 HISTGR - NCLASS .NE. NPTS (IFLAG=2)
66 IFLAG = 2 signals a special case in which the input data has
67 already been accumulated into class intervals. Therefore, the
68 number of data values, NPTS, and the number of histogram bars,
69 NCLASS, must be equal.
70 HISTGR - NCLASS .NE. NPTS (IFLAG=3)
72 IFLAG = 3 signals a special case in which the input data has
73 already been accumulated into class intervals. Therefore, the
74 number of data values, NPTS, and the number of histogram bars,
75 NCLASS, must be equal. (IFLAG = 3 differs from the IFLAG = 2
76 case only in the fact that two histograms are to be displayed
77 instead of one.)
78 HISTGR - NCLASS MUST EQUAL NPTS
80 This is a redundant test on whether the number of input data
81 values, NPTS, equals the number of bars, NCLASS, when the IFLAG
82 option is 2 or 3.
83 HISTGR - IFLAG NOT SPECIFIED OR INVALID
85 HISTGR argument IFLAG is not one of the legal values of 0, 1, 2,
86 or 3.
87 HISTGR - MIN. X-VALUE .EQ. MAX. X-VALUE
89 A histogram has no width. This probably means the values of
90 HISTGR argument CLASS have been entered in error.
91 HISTGR - MAXIMUM Y-VALUE .EQ. 0.0
93 A histogram has no data. The histogram is plotted with a Y
94 range of .02. This probably means the HISTGR argument DAT1 had
95 all zero values.
96 HISTGR - WINDOW OPTION ERROR, RANGE IS 0. - 1.
98 The internal parameter options that define the part of the frame
99 where the histogram is to be drawn have been entered
100 incorrectly.
101 HSTOPC - UNDEFINED OPTION
103 HSTOPI - UNDEFINED OPTION
105 HSTOPL - UNDEFINED OPTION
107 HSTOPR - UNDEFINED OPTION
109 Either an internal parameter name or value is incorrect. Check
110 the spelling in the calls to whichever routine is cited.
111 HSTOPI - LCOL MUST EQUAL 8
113 The number of color indices input to HSTOPI cannot exceed 8.
114 HSTOPR - INVALID SPACING PARAMETER
116 Either the spacing of histogram bars, or the overlap of bars
117 from two histograms, is outside of the legal range. Valid
118 values for spacing of bars are 0.0 (no spacing) to 4.0 (maximum
119 spacing.) Valid values used to set overlap of adjacent
120 histogram bars when comparing two datasets in one histogram are
121 -4.0 (maximum overlap) to 4.0 (little or no overlap.)
122
124 Online: histgr, histogram_params, hstopc, hstopi, hstopl, hstopr,
125 ncarg_cbind
126 Hardcopy: NCAR Graphics Fundamentals, UNIX Version
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130 Copyright (C) 1987-2007
131 University Corporation for Atmospheric Research
132 This documentation is free software; you can redistribute it and/or
134 modify it under the terms of the GNU General Public License as
135 published by the Free Software Foundation; either version 2 of the
136 License, or (at your option) any later version.
137 This software is distributed in the hope that it will be useful, but
139 WITHOUT ANY WARRANTY; without even the implied warranty of
140 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
141 General Public License for more details.
142 You should have received a copy of the GNU General Public License along
144 with this software; if not, write to the Free Software Foundation,
145 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
146UNIX March 1993 Histogram(3NCARG)