the formula to draw the Spherical circle

[ronke]

dose anyone know the formula to draw the Spherical circle like below, thanks.

[Bob_Schor]

Do you know about spherical polar coordinates, as well as lines of longitude and latitude?  If we call the Radius "R = 1", the Polar angle "Phi", and the Azimuth angle "Theta", a circle of Longitude at a fixed Theta (and R) is simply drawn by having Phi go from 0 to pi (assuming 0 is the North Pole), while a circle of Latitude fixes Phi and lets Theta go from 0 to 2 pi (this will, of course, draw around the back side of the Globe, but you can just draw the front half-sphere by letting Theta go from 0 to pi).

Note that this is a 3-D graph (which LabVIEW can produce).  You can "do the math" and compute the equations for the 2D projection of the 3D plot, of course ...

Bob Schor

Bob Schor

[wiebe@CARYA]

There's a 2D polar plot in Graphics & Sound>Picture Plots...

That might not answer the question. Or actually it does imply a "yes" (yes, somebody knows the formula to draw the Spherical circle).

[altenbach]

Your two grids are not the same, but look up "Wulff net" and "Schmidt net" to see which one is closer to your needs.

[ronke]

Dear altenbach,

          Thanks for you reply, it seem like the Schmidt net after compare the graph, do you know how to draw it ?

thanks for your help in advance.

[ronke]

I have found the formula in the attached, I will try to draw this Schmidt net (equal-area projection）。

[ronke]

I have finished this graph.

[ronke · Accepted solution]

for the vi, please refer this link:

https://forums.ni.com/t5/LabVIEW/How-to-draw-the-ISOcandla-diagram-2D-sphere/m-p/3935627#M1118623