Gnuplot and Spherical/Cylindrical plotting

Question

I have some questions with plotting in 3D withe Gnuplot I need to plot some data (from files) in spherical coordinates. My data are organized as following,

azimuth   zenith    intensity  

1    2    0.256e-2  
2    2    0.156e-2  
3    3    ...            

I use:

splot "data.out" using 1:2:3

but the third column is used as a radius...so if I want to compare 2 different set of datas, with different intensity, my plot become unreadable

is there a way to fix the radius to a specific value instead of using the third column as radius?

Sorry for the long post (-: (and the mistakes...I'm not a native English speaker) Thanks a lot for your help Hyppie-Psi

Answer 1

I'm not completely sure that I understand what you are looking for but you can do some operation on the using 1:2:3 part. For instance, if you write

splot "data.out" using 1:2:(12.3)

you will have the z coordinate of 12.3 for all your x and y points. You can also do more complicated operations, like

splot "data.out" using 1:2:($3*$3)

where you square the third column of your data file. You can also for instance go in spherical coordinate by doing:

splot "data.out" using ($3*cos($1)*cos($2)):($3*sin($1)*cos($2)):($3*sin($2))

which, if I understood your question, is equivalent to simply

set mapping spherical
splot "data.out" using 1:2:3

With these informations, you should be able to perform any operation you like on your third column data to display in a way you like.