Use a simple ASCII input file to plot a single X,Y data set with the python matplotlib package. I have also prepared some simple examples of how to build some plot codes that do more complicated things (like using multiple symbols, etc...). In this version of the S-series (S=simple) the input file is expected to have 4 columns of data: X, Xerr, Y, Yerr. The error bars for each axis are plotted for every point.

I wrote a script named mpl that provides a brief summary of point type a color properties.

Notice below that the error bars, if small, can greatly interfere with the color of the points. Hence, I later wrote a simpler version of this code named pxy_S_scat.py that reads and plots only X,Y values.

A set of example file and some README helps are in the $TDATA directories (got, T_runs/pxy_S_scat.py/ex0). You can use the "-h" flag to learn about the arguments for this code:

 
% pxy_Serr_scat.py -h 
usage: pxy_Serr_scat.py [-h] [-v] arg1 arg2 arg3 arg4 arg5

positional arguments:
  arg1           input data file
  arg2           low value for X axis
  arg3           high value for X axis
  arg4           low value for Y axis
  arg5           high value for Y axis

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  Verbose responses

 
% cat dat.1
Some Data I Have                   # Main title
Parameter A                        # X label
The Y Parameters (in a string)     # Y label
r * 100                            # Symbol (color,type,size)
Set 12 Name                        # Info string for a data label
1.0 0.4  1.1  1.22                 # x, err_x, y, err_y
2.0 0.1  1.9  0.10
3.0 0.2  3.1  0.55
4.0 0.3  4.4  0.28
5.0 0.1  4.6  0.26
% pxy_S_scat.py dat.1 0.0 7.0 -1.0 9.0 

A sample plot from pxy_S_scat.

A more typical plot in the $TDATA example set is made using the input file named "dat.spirals". To generate the plot:

 
% pxy_Serr_scat.py dat.spirals 0.8 1.8 10.0 17.0 

A sample plot from pxy_S_scat using RC3 spiral galaxy data.

I wondered about how to change the symbol types. I googled "symbol attributes in matplotlib scatter plot" and found lots of things, the second of which was very useful!. For the sake of completeness in my offline notes, I show a small part of a graphic from that webdoc below:

Examples of marke types.

For color specification:

 
Commands which take color arguments can use several formats 
to specify the colors. For the basic built-in colors, you 
can use a single letter:

        b: blue
        g: green
        r: red
        c: cyan
        m: magenta
        y: yellow
        k: black
        w: white

Gray shades can be given as a string encoding a float in 
the 0-1 range, e.g.:

  color = '0.75'

For a greater range of colors, you have two options. You can 
specify the color using an html hex string, as in:

color = '#eeefff'