Yi-Chuan, If I understand your question correctly, you want to convert geopotential (gp) -- which is available in your bering_pre.nc file -- to height (z). You can do this by "Define a grid diagnostic" formula and using the GP2Z(gp)formula http://www.unidata.ucar.edu/software/idv/docs/workshop/formulas/DoingMoreFormulas.html http://www.unidata.ucar.edu/software/idv/current/docs/userguide/tools/JythonLib.html At any rate, you can find various formulas and functions in the IDV documentation which can hopefully do what you are trying to achieve. https://www.unidata.ucar.edu/software/idv/docs/workshop/formulas/index.html Best, Unidata IDV Support > Full Name: Yi-Chuan > Email Address: address@hidden > Organization: National central university > Package Version: 5.2 build date:2015-08-26 18:19 UTC > Operating System: Windows 8.1 > Hardware: Java: home: D:\IDV_5.2\jre version: 1.8.0_45 > j3d:1.6.0-pre9-daily-experimental daily > Description of problem: > > Hi, > > How do I do to transform pressure level into z level and create a variable > name "pressure" at z level ? > > Ticket Details =================== Ticket ID: BXH-959682 Department: Support IDV Priority: Normal Status: Closed