Octave plotting x axis precision

Question

I wonder how can I increase the precision of the x/y axis when I am plotting the graph.

I have initialised the option long and I have a data set for example:

x(1:3) 
ans = 

736330.576631944 
736330.576643519 
736330.576655093 

y(1:3) 
ans = 

-62 
-63 
-62 

and when I do plot(x(1:3),y(1,3)), i can only see a straight vertical line between -62 and -63, it seems like that the x axis doesnt have enough decimal places to recognise the changes.

get(gca, 'xticklabel') 
ans = 
{ 
[1,1] = -2e+006 
[1,2] = -1.5e+006 
[1,3] = -1e+006 
[1,4] = -500000 
[1,5] = 0 
[1,6] = 500000 
[1,7] = 1e+006 
[1,8] = 1.5e+006 
}

This is what I get from the get gca() function. Is there anyway to increase the precision of the x axis so that I can see the data point moving ?

Thank you very much for the help

Answer 1

OpenGL uses class single to represent numbers. So any graphics_toolkit which uses OpenGL (qt and fltk) have that problem with single precision.

So either switch graphics_toolkit to gnuplot which uses double or remove the constant part in your case x=xx(1) after creating the ticklabels with datenum so that single precision is enough to distinguish values.