Re: [ferret_users] extracting info from axes

[Ge Peng <gpeng@xxxxxxxxxxxxxxxxxxxxxxx>]

Hi Ansley:

I am able to create labels I want dynamically based on the suggestions you
and Bill made.

Thanks so much for detailed suggestions and examples - they are very helpful.

--- Peng

> Hi Ge Peng,
> Billy's suggestions will all work well. I have some more ideas to add as
> well.  The RETURN= keyword will also give you access to information
> about the variable and grid.
>
> If var is a variable in your dataset, then you can use `var,return= `
> will give you the axis ends in the current context you have set with a
> "set region", and also the units of the variable or the axes.  For
> example,
>
> yes? set region/i=33/j=12/k=5/l=23
> yes? define symbol label_ijkl = \
>   `var,return=xstart`, `var,return=ystart`, depth(`var,return=zunits`):,
> `var,return=zstart`, `var,return=tstart`
>
> yes? show symbol label_ijkl
>
> You can control the precision of the output by adding a precision
> specifier, for example, `var,RETURN=tstart,precision=3` and you can turn
> the labeling of the longitude and latitude outputs on or off by setting
> or canceling the modes LONG_LABEL and LATIT_LABEL.
>
> The functions TAX*  also give you ways to return a date string,
>
> yes? show function TAX*
>
> Ansley
>
>
> William.S.Kessler wrote:
>> Hi Ge Peng -
>>
>> Any quantity that is written on a default plot is available as a symbol.
>>
>> For example, if you:
>>
>> plot/i=242/j=14/k=22/l=8 varname
>>
>> The plot and title will contain the information you want (perhaps in
>> the upper left corner, or in the title below the plot).
>>
>> AFTER making such a plot, these symbols will be found by:
>>
>> yes? ppl listsym
>>
>> These symbols will generally be numbered lab4, lab5, lab6, ....
>> (lab1,2,3 are the standard Ferret info that appears in the upper right
>> corner of the plot).
>>
>> You can write these in subsequent plots as follows:
>>
>> label xpos ypos center angle size ($lab4)
>>
>> And, you can get fancier by noticing that these label numbers are
>> flagged by other symbols in the list. You don't have to do that long
>> listing every time. For example, the label for the plot longitude (if
>> it is relevant) is flagged by the symbol labnum_x. So, you can always
>> write the longitude by:
>>
>> label xpos ypos center angle size ($lab($labnum_x))
>>
>> In addition to the location identifiers, there are also the labels for
>> the dataset (flagged by labnum_dset) and others as appropriate.
>>
>> The one rule to remember is that these symbols are defined ONLY AS THE
>> PLOT IS DRAWN. You MUST make a standard plot (without /NOLABEL) to
>> define them before you can use them.
>>
>> Billy K
>>
>>
>> On 18/02/2009, at 4:19 PM, Ge Peng wrote:
>>
>>> Hi Ferret Users,
>>>
>>> Apology if this request is too elementary.
>>>
>>> I would like to extract grid info from a data set for the purpose of
>>> labeling. For example, for a given region/i=242/j=14/k=22/l=8, I have
>>> the
>>> lon, lat, z, and time as follows:
>>>
>>> yes? list x[gx=xt_ocean]
>>>              VARIABLE : X
>>>                         axis XT_OCEAN
>>>              LONGITUDE: 38.5W(-38.5)
>>>          -38.50
>>> yes? list y[gy=yt_ocean]
>>>              VARIABLE : Y
>>>                         axis YT_OCEAN
>>>              LATITUDE : 68.5S
>>>          -68.50
>>> yes?  list z[gz=zt_ocean]
>>>              VARIABLE : Z
>>>                         axis ZT_OCEAN
>>>              DEPTH (m): 215
>>>           215.0
>>>
>>> yes? list t[gt=TIME]
>>>              VARIABLE : T
>>>                         axis TIME
>>>              TIME     : 07-FEB-1999 12:00 JULIAN
>>>           2228.
>>>
>>> I would like to define a label, which should be something like
>>> "38.5W, 68.5S, DEPTH (m): 215, 07-FEB-1999"
>>>
>>> Of cause, it will be different for a different region if I change
>>> i,j,k,
>>> or l values.
>>>
>>> Is it a way to create the label dynamically?
>>>
>>> Thanks,
>>>
>>> --- Peng
>>>
>>>
>>>
>>
>