## GSLIB Help Page: HISTPLT

Description:

- `histplt` has been custom written to generate some univariate statistical summaries and a visual output that is compatible with a PostScript display device. The input data is a variable from a simplified Geo-EAS input file where the variable in another column can act as a weight (declustering weight, specific gravity, thickness for 2-D data,...). These weights do not need to add up to one. Minimum and maximum trimming limits can be set to remove missing values and outliers. The program will automatically scale the histogram. The user can choose to set the minimum and maximum histogram limits, number of classes, and whether or not to use a logarithmic scale.

Parameters:

- datafl: the data file in a simplified Geo-EAS format.
- ivr and iwt: column number for the variable and the weight. If iwt less than or equal to 0, equal weighting is considered.
- tmin and tmax: all values strictly less than tmin and strictly greater than tmax are ignored.
- outfl: file for PostScript output.
- hmin and hmax: minimum and maximum plotting limits for the variable axis (abscissa). These do not have to be compatible with tmin and tmax Values that are less than hmin or greater than hmax will appear just beyond either end of the histogram plot. They contribute to the statistics calculated. Setting hmin greater than hmax will cause the program to set the limits to the minimum and maximum data values encountered.
- fmax: maximum frequency value for plotting vertical axis. The maximum will be determined automatically if fmax is set less than 0.0. This option is used to force the same histogram axis for different sets of data.
- ncl: the number of classes.
- ilog: =0 then an arithmetic scaling of the variable scale is used, =1 then a logarithmic scaling (base 10) is used.
- icum: =0 then a frequency histogram will be constructed, =1 then a cumulative histogram will be constructed.
- ncum: the number of quantiles to plot when constructing a cumulative histogram
- ndec: the number of decimal places to use for the statistics annotated on the histogram plot (if set to 0, then the number will be automatically determined).
- title: a 40-character title for the top of the plot.
- pos: positioning of statistics. At times it is desirable to move the statistics from right to left to avoid overwriting the histogram bars (pos=1 is the left and pos=1 is the right).
- refval: reference value for a box plot under the histogram. If this value is within the allowable range specified by tmin and tmax then a label on the horizontal X axis will not be plotted and, instead, a box plot will be shown (outside whiskers at the 95% probability interval, inside box at the 50% probability interval, vertical solid line at the median, and black dot at the reference value specified by refval)