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pshistogram - Calculate and plot histograms


pshistogram [ table ] -Jx|Xparameters
-Wbin_width[+l|h|b] [ -A ] [ -B[p|s]parameters ] [ -Ccpt ] [ -D[+b][+ffont][+ooff][+r] ] [ -F ] [ -Gfill ] [ -Jz|Zparameters ] [ -I[o|O] ] [ -K ] [ -Lpen ] [ -N[mode][+ppen] ] [ -O ] [ -P ] [ -Q ] [ -Rregion ] [ -S ] [ -U[stamp] ] [ -V[level] ] [ -Xx_offset ] [ -Yy_offset ] [ -Z[type][+w] ] [ -bibinary ] [ -dinodata ] [ -eregexp ] [ -fflags ] [ -hheaders ] [ -iflags ] [ -pflags ] [ -ttransp ]

Note: No space is allowed between the option flag and the associated arguments.


pshistogram reads file [or standard input] and examines the first data column (or use -i) to calculate histogram parameters based on the bin-width provided. Using these parameters, scaling, and optional range parameters it will generate PostScript code that plots a histogram. A cumulative histogram may also be specified.


xscale[/yscale] (Linear scale(s) in distance unit/data unit).

Sets the bin width used for histogram calculations. The modifiers specify the handling of extreme values that fall outside the range set by -R. By default these values are ignored. Use +b to let these values be included in the first or last bins. To only include extreme values below first bin into the first bin, use +l, and to only include extreme values above the last bin into that last bin, use +h.


One or more ASCII (or binary, see -bi[ncols][type]) data table file(s) holding a number of data columns. If no tables are given then we read from standard input.

Plot the histogram horizontally from x = 0 [Default is vertically from y = 0]. The plot dimensions remain the same, but the two axes are flipped.

Set map boundary frame and axes attributes.

Give a CPT. The mid x-value for each bar is used to look-up the bar color.

Annotate each bar with the count it represents. Append any of the following modifiers: Use +b to place the labels beneath the bars instead of above; use +f to change to another font than the default annotation font; use +o to change the offset between bar and label [6p]; use +r to rotate the labels from horizontal to vertical.

Center bin on each value. [Default is left edge].

Select filling of bars [Default is no fill].

Inquire about min/max x and y after binning. The xmin xmax ymin ymax is output; no plotting is done. Append o to output an ASCII table of the resulting x,y data instead. Upper case O will output all x,y bin data even when y == 0.

Set z-axis scaling; same syntax as -Jx.

Do not finalize the PostScript plot.

Draw bar outline using the specified pen thickness. [Default is no outline].

Draw the equivalent normal distribution; append desired pen [0.5p,black]. The mode selects which central location and scale to use:
  • 0 = mean and standard deviation [Default];
  • 1 = median and L1 scale;
  • 2 = LMS mode and scale.

The -N option may be repeated to draw several of these curves.

Append to existing PostScript plot.

Select "Portrait" plot orientation.

Draw a cumulative histogram.

Specify the region of interest.

For perspective view p, optionally append /zmin/zmax. (more ...) If not given, pshistogram will automatically find reasonable values for the region.

Draws a stairs-step diagram which does not include the internal bars of the default histogram.

Draw GMT time stamp logo on plot.

Select verbosity level [c].


Choose between 6 types of histograms:
  • 0 = counts [Default]
  • 1 = frequency_percent
  • 2 = log (1.0 + count)
  • 3 = log (1.0 + frequency_percent)
  • 4 = log10 (1.0 + count)
  • 5 = log10 (1.0 + frequency_percent).

To use weights provided as a second data column instead of pure counts, append +w.

Select native binary input. [Default is 2 input columns].

Replace input columns that equal nodata with NaN.

Only accept data records that match the given pattern.

Specify data types of input and/or output columns.

Skip or produce header record(s).

Select input columns and transformations (0 is first column).

Set PDF transparency level in percent.

-^ or just -
Print a short message about the syntax of the command, then exits (NOTE: on Windows just use -).
-+ or just +
Print an extensive usage (help) message, including the explanation of any module-specific option (but not the GMT common options), then exits.
-? or no arguments
Print a complete usage (help) message, including the explanation of all options, then exits.


To draw a histogram of the data v3206.t containing seafloor depths, using a 250 meter bin width, center bars, and draw bar outline, use:

gmt pshistogram v3206.t -JXh -W250 -F -LP0.5p -V >

If you know the distribution of your data, you may explicitly specify range and scales. E.g., to plot a histogram of the y-values (2nd column) in the file errors.xy using a 1 meter bin width, plot from -10 to +10 meters @ 0.75 cm/m, annotate every 2 m and 100 counts, and use black bars, run:

gmt pshistogram errors.xy -W1 -R-10/10/0/0 -Jxc/0.01c \

-Bx2+lError -By100+lCounts -Gblack -i1 -V >

Since no y-range was specified, pshistogram will calculate ymax in even increments of 100.


The -W option does not yet work properly with time series data (e.g., -f0T). Thus, such variable intervals as months and years are not calculated. Instead, specify your interval in the same units as the current setting of TIME_UNIT.


gmt, gmtcolors, psbasemap, psrose, psxy


2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe

May 21, 2019 5.4.5