Hi Martin, cancel axis/modulo really should do what you need. Make sure that any time you save the data you have issued that command. Try this sequence, use etopo20In a new session, see that even though there is not a modulo attribute on the X axis, Ferret treats the axis as modulo So we have to cancel it again. use sub.ncThe longitude axis in sub.nc still does not have a modulo attribute. The topic in the documentation is "subspan modulo axes". We have strong reasons to have this behavior as the default, so that datasets can be compared even if they use different representations of the longitude coordinates. Ansley On 4/20/2012 9:49 AM, Martin Schmidt wrote: Hi Karl, thanks for the suggestion with cancel mode upcase I was not aware of this option. It helps to prevent that the new axis is written! This solves the problem. Why I want to cancel the module attribute? My region covers only 15 degrees and some subsequent tools look if the data are modulo or not. So I simply want to have correct attributes. Many thanks for your help, Martin Karl Smith wrote:Hi Martin, Does 'cancel mode upcase' solve your original problem of new axes with uppercase names? It also seems surprising to me that you don't want your longitudes to have a modulo of 360 degrees. Not sure why your 'cancel axis/modulo' call isn't working for you. You might want to 'set mode verify' to make sure your command is doing what you think it is doing. yes? def axis /X=5E:35E:1 /modulo=75 xax yes? sh axis xax name axis # pts start end XAX LONGITUDE 31mr 5E 35E Axis span (to cell edges) = 31 (modulo length = 75) yes? can axis /modulo xax yes? sh axis xax name axis # pts start end XAX LONGITUDE 31 r 5E 35E Axis span (to cell edges) = 31 Karl On Fri, Apr 20, 2012 at 3:06 AM, Martin Schmidt <martin.schmidt@xxxxxxxxxxxxxxxxx> wrote:Hi, I have a given regional data set stored in a netcdf-file topo.dta.nc. The axes are lat/lon, no modulo attribute is defined. I derive a new variable from a variable in the data set and hope to have it defined at the same axis. For example: let htp_closed = if i[gx=htp] eq 1 the 1/0 else htp My choice would be to append the variable to the existing file. However, I cannot force ferret to use the same axis, xt_i, yt_j. Instead two new capital XT_I, YT_J show up which are stored separately and have new attributes different from the original axes. This confuses a program to read the data later. Putting the new variable onto the old grid using @asn does not help either. So I try to write to a new file; save/clobber/file=my_new_file.nc htp_closed Doing so, I get the modulo attribut set to 360 in the x- axis. can axis/modulo `htp_closed,return=xaxis` does not remove the modulo attribute. Also using the explicit axis name does not help. How can I get rid of the wrong modulo attribute in the frame of ferret? Would it be possible to change the behaviour of ferret in future releases in such a way, that a modulo attribute must be set if it is required and correct, or is inherited from other axis that are modulo? Dealing with regional data the automatic choice of ferret is always wrong and it reveals as very stiff to produce correct data. Many thanks, Martin Schmidt |