Plot 0s & 1s Matrix in GNUplot: Solve "No Usable Data" Error

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SUMMARY

The forum discussion addresses the "No usable data" error encountered when plotting a 50x50 matrix of 0s and 1s using GNUplot. The user attempted to plot the data with the command splot 'C:\Users\raf\Desktop\PolymerProject\monteCarloCode\directionInitial.txt' with pm3d but received warnings indicating unreadable files and undefined x values. The issue was identified as a potential mismatch in the data file format, which should follow a specific structure where rows are separated by blank lines and x values are consistent within each data block.

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This discussion is beneficial for data analysts, researchers, and students who are using GNUplot for visualizing binary data matrices and need to troubleshoot common plotting errors.

rolotomassi
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I have a .txt file which is 50 rows x 50 columns filled with entirely 0's and 1's.

I have tried to plot the data with and without spaces between each column.

I keep getting this message:

gnuplot> splot 'C:\Users\raf\Desktop\PolymerProject\monte carlo code\directionInitial.txt' with pm3d
warning: Skipping unreadable file "C:\Users\raf\Desktop\PolymerProject\monte carlo code\directionInitial.txt"
warning: No usable data in this plot to auto-scale axis range
^
All points x value undefined

None of the advice online seems help/solve my problem. New to gnuplot so excuse me if this is obvious.
 
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rolotomassi said:
I have a .txt file which is 50 rows x 50 columns filled with entirely 0's and 1's.

I have tried to plot the data with and without spaces between each column.

I keep getting this message:

gnuplot> splot 'C:\Users\raf\Desktop\PolymerProject\monte carlo code\directionInitial.txt' with pm3d
warning: Skipping unreadable file "C:\Users\raf\Desktop\PolymerProject\monte carlo code\directionInitial.txt"
warning: No usable data in this plot to auto-scale axis range
^
All points x value undefined

None of the advice online seems help/solve my problem. New to gnuplot so excuse me if this is obvious.
Please post your code. Attaching your text file might be helpful, as well.
 
This what I enter into the command box:

gnuplot> set pm3d map
gnuplot> splot 'C:\Users\raf\Desktop\PolymerProject\monteCarloCode\directionInitial.txt'

As I said I've tried various different spacings in the .txt file.
 

Attachments

Just as I read my post back I realized I have entered the incorrect path file.
 
rolotomassi said:
This what I enter into the command box:

gnuplot> set pm3d map
gnuplot> splot 'C:\Users\raf\Desktop\PolymerProject\monteCarloCode\directionInitial.txt'

As I said I've tried various different spacings in the .txt file.
I found this documentation -- http://theochem.ki.ku.dk/on_line_docs/gnuplot/gnuplot_36.html
Your data file doesn't seem to match the format used in this example.
A simple example of plotting a 3-d data file is
splot 'datafile.dat'where the file "datafile.dat" might contain:

# The valley of the Gnu.
0 0 10
0 1 10
0 2 10

1 0 10
1 1 5
1 2 10

2 0 10
2 1 1
2 2 10

3 0 10
3 1 0
3 2 10

Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of 3 points each ). Rows (datablocks) are separated by blank records.

Note also that the x value is held constant within each dataline. If you instead keep y constant, and plot with hidden-line removal enabled, you will find that the surface is drawn 'inside-out'.

Actually for grid data it is not necessary to keep the x values constant within a datablock, nor is it necessary to keep the same sequence of y values. gnuplot requires only that the number of points be the same for each datablock. However since the surface mesh, from which contours are derived, connects sequentially corresponding points, the effect of an irregular grid on a surface plot is unpredictable and should be examined on a case-by-case basis.
 

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