I prefer pgr over Matlab because Matlab is expensive (and thus not available on all machines I use), monolithic and slow to start up, and cumbersome. Using pgr which is a thin wrapper around some very nice open-source Python code I didn’t have to write, I can direct data (printed by any program in any language) straight into a plotter and look at the results within an eyeblink. pgr starts up quickly, reads from standard input, and is scriptable.

Data may be displayed to the screen or to an .eps file. I am using the latter, on a large scale, for presentation graphics in my doctoral dissertation.

While pylab has support for 2D contour plots, my pgr wrapper doesn’t yet handle this (but easily could be modified to do so).

The version of pylab I’m using does not appear to support 2D surface plots at all. So, I still have reason to use Matlab from time to time.

pgr takes as input one or more vectors, and creates an X/Y plot of them. The user specifies whether:

• the first column of the data file is the abscissa and the rest are ordinates (default), or
• all columns of the data file are ordinates and the abscissa is taken from the line number (via the -n command-line option).

For example, suppose an input data file is as follows:

1 2
3 7
5 9

With -n, pgr plots two lines: (1,1) (2,3) (3,5), and (1,2) (2,7) (3,9).

Without -n, pgr plots one line: (1,2) (3,7) (5,9).

• Click the magnifying glass icon.
• Rubber-band an area of the screen with the left mouse button to zoom in.
• Do that with the right mouse button to zoom out.
• Use the arrow buttons to move back and forth through your zoom/pan history.
• Click the house icon to go to the original zoom/pan.
• Click the disk icon to save the plot as a file. (Or, re-run pgr with -o myfilename.eps.)

Usage: ./pgr [options] [file name]
Use "-" as file name, or omit it, if input is stdin.
Options:
  --help                 Print this message.
  -title {title text}    Specify plot title.
  -xlabel {x label text} Specify x label.
  -ylabel {y label text} Specify y label.
  -labels 'x y1 y2'      Specify legend labels.
  -flabels               Take x label and legend labels from data file.
  -width {inches}        Specify figure width.
  -height {inches}       Specify figure height.
  -xmin {xmin}:          Specify manual bounds.
  -xmax {xmax}:          Specify manual bounds.
  -ymin {ymin}:          Specify manual bounds.
  -ymax {ymax}:          Specify manual bounds.
  -n                     Take x coordinate from line number.
  -l                     Draw lines only.
  -p                     Draw points only.
  -lp                    Draw lines and points.
  -lines                 Line-draw mode.  Input should be
                         quadruples of x1 y1 x2 y2.
  -ms {n}                Marker size (default 5) for points.
  -formats '- -- o'      Specify pylab-style marker formats.
                         Examples:
        - solid line       --    dashed line       -.    dash-dot line
        : dotted line      .     points            o     circle symbols
        s square symbols   +     plus symbols      x     cross symbols
        See help(pylab.plot) inside Python for more information.
  -colors 'red blue green' Specify line colors.
  -errorbar              1st column is  x, 2nd is y, 3rd is err(y).
  -bar                   Plot a bar chart.
  -barwidth {w}          Specify bar width for -bar.
  -grid                  Include a background grid.
  -1ox,-1my              Compute 1/input or 1-output before plotting.
  -logx,-logy,-loglog    Plot log of input, output, or both.
  -o {file name}         Write file instead of graphing.
                         Formats: .png, .eps.
  -dpi {number}          Dots per inch for -o.

I am actively using pgr, and I add features to it as they become necessary. I do not see suppport for 2D surface plots in the near future.

pgr is released under the terms of the BSD 3-clause license. Please see the file LICENSE.txt for more details.