How to Create a 2-D Contour Plot with Labels Using Gnuplot?

[hamidamini]

Hello
with gnuplot
I need to have 2d contour plot from a file (say ss.dat) with three column, first and secend columns are X and Y respectively and the third column is magnitude (I need to have this magnitude with labels on it in 2d plot).

Thanks in advance
Hamid

 

[LeePhillips]

Assuming your file contains grid data, the basic commands to generate a contour plot would be

set contour base
unset sur
set view map
splot 'file'

gnuplot will generate a key mapping dash patterns in the contours to values. If you want actual numerical labels printed on the contours, you have to resort to tricks. I describe one way to do it in the gnuplot Cookbook.

 

[hamidamini]

Thank you very much. my file dose not have grid data. it just has three coulmn first is "x"axis second "y" and third is just the data I want to have the plot of. How can I grid x and y axis.

Thanks

 

[LeePhillips]

Your data might already be in grid form, depending on how it is organized. Type "help grid_data" at the gnuplot interactive prompt to find out what this means. Even if it is not, the plot might work. Try it and see. If your data is scattered you might be able to plot it after letting gnuplot convert it into a grid arrangement. Type "help dgrid3d" to find out how to do this.

 

[alphy]

Hi Hamid,

Thank you for your question. I am familiar with using gnuplot to create 2-D contour plots from data files. To create a contour plot, you will need to use the "splot" command in gnuplot, which is used specifically for creating 3-D plots.

To create a 2-D contour plot, you will need to use the "set view map" command before the "splot" command. This will project the 3-D plot onto a 2-D plane, creating a contour plot.

To plot data from a file, you will need to use the "using" keyword after the "splot" command, followed by the column numbers of the data you want to plot. In your case, it would be "using 1:2:3" to plot the X, Y, and magnitude columns respectively.

To add labels to your contour plot, you can use the "set label" command, followed by the coordinates and text for your label. You can also customize the appearance of your contour plot using various gnuplot commands such as "set title", "set xlabel", and "set ylabel".

I hope this helps you create your desired 2-D contour plot using gnuplot. Best of luck with your research.

Sincerely,