Hi Cesar, This can be found in the Users Guide under "sigma coordinate data".  The function to use is the ZAXREPLACE function, where you will define a Z axis in terms of height and use the function to put your "levels" data onto that. I've just added some more index entries and cross-references to the Users Guide, so the information is be easier to find.  There are several examples, so give it a try and write back here to the users list if you need  any help. Ansley TEJEDA HERNANDEZ, CESAR wrote: ```Thank you for your help. It worked perfectly. I have another question: I have a variable "modulus" that gives me the wind in m/seg for I,j,k. But the k coordinate comes in 'sigma levels' and I want it interpolated at some heights in meters. The values for al sigma levels are given by the variable altz, and this is a variable that depends on I,j (on K too). So, I can get the sigma level for 60 m for each I,j with the Following command: let micooz=mialtz[z=2:6@loc:60] But now, I do not know how to use it to extract the interpolation of modulus in the sigma levels specified in micooz. Thank you very much, César. -----Original Message----- From: Jaison Kurian [mailto:jaison@caos.iisc.ernet.in] Sent: 26 September 2006 12:26 To: TEJEDA HERNANDEZ, CESAR Cc: ferret_users@noaa.gov Subject: Re: [ferret_users] Creating custom variable along z axis. Hi Cesar, You can use ZSEQUENCE function to define a 1D array (on Z-axis). From user manual, Ch3 Sec2.3.25 : XSEQUENCE(A), YSEQUENCE(A), ZSEQUENCE(A), TSEQUENCE(A) Unravels the data from the argument into a 1-dimensional line of data on an ABSTRACT axis. So try something like this, yes? let f2s = ZSEQUENCE({1, 0, 0, 0, 0}) Now f2s will be on a "ABSTRACT" axis. If you want to assign a proper Z axis, then yes? define axis/z=1:5:1 zax yes? let f2s_z = f2s[gz=zax@ASN] ! @ASN regridding just assigns the ! axis Regarding the error message you got : let f2s= {1, 0, 0, 0, 0} --> will define f2s on X-axis (the default way) and it does not have any other valid axes. So when you try set variable/grid=migrid f2s there is a mismatch...like variable have only X-axis and the destination grid does have only Z-axis. This way it won't work. That is why Ferret warns that "Grid for a user-defined variable is implied by its definition" If you want to remap from X to Z axis, you have to use RESHAPE function. In the solution i suggested earlier, the variable is defined on "Z" axis and the regridding is done on Z-Axis ..so it is consistent. Hope This Helps, Regards, Jaison On Tue, 26 Sep 2006, TEJEDA HERNANDEZ, CESAR wrote: ``` ```Hello, I want to create a variable with these values: let f2s= {1, 0, 0, 0, 0} But along z axis (not x). This statements are not useful after the definition: yes? define axis /z=1:5:1 zaxis yes? define grid /z=zaxis migrid yes? set variable/grid=migrid f2s **ERROR: invalid command: cannot specify grid for f2s Grid for a user-defined variable is implied by its definition ¿Any hint? Thanks in advance. César. ``` ``` ``` ```-- ~> ~> ~> ~> ~> ~> ~> ~> ~> ~> ~> Ansley Manke, NOAA/PMEL ansley.b.manke@noaa.gov 7600 Sand Point Way NE, Seattle WA Phone 206-526-6246, FAX 206-526-6744 ```