[idvusers] Plot isosurface with ascii file

Dear all,

I'm a neophyte who wants to use IDV to plot velocity isosurface in the mantle 
with tomographic results.
I have ascii data with columns of lat, lon, depth and velocity.
However, I couln't find information about how to convert ascii data to grid 
data (*.nc) to plot isosurface in userguide.
There is only practice to plot isosurface with preexisted grid data.

I'd appreciate it if you'd let me know how to plot isosurface with this kind of 
ascii data.
Thank you in advance.

Regards,
Sung-Joon Chang

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  Sung-Joon Chang
 
Postdoctoral Fellow
Dept. of Earth and Planetary Sciences
Northwestern University
1850 Campus Drive
Evanston, IL 60208-2150
U.S.A.
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