[ncl-talk] Problem with overlay plot
Mary Haley
haley at ucar.edu
Fri Aug 22 08:21:09 MDT 2014
Ipsita,
I took this offline to ask Dennis about it. Here's what he responded:
There is no function to convert height to pressure.
[1] *If* she had temperature and surface geopotential she could use:
https://www.ncl.ucar.edu/Document/Functions/Built-in/hydro.shtml
[2] If she does not have the above, there is no existing equation(s) that
can
be used.
[3] A poor-man (poor-woman) approach would be to use
https://www.ncl.ucar.edu/Document/Functions/Built-in/stdatmus_z2tdp.shtml
This maps the height into the U.S. Standard Atmosphere climatological
height.
---
z = (/0, 100, 500, 7500, 25000, 84000 /)
tdp = stdatmus_z2tdp(z) ; ===> tdp(3,6)
print(tdp(0,:)+" "+tdp(1,:)+" "+tdp(2,:))
---
0) 15 1.225 1013.25
(1) 14.35 1.21328 1001.29
(2) 11.75 1.16727 954.608
(3) -33.75 0.556623 382.514
(4) -51.5 0.0394658 25.1102
(5) -84.5 8.05098e-06 0.00435981
--Mary
On Wed, Aug 20, 2014 at 10:10 PM, Ipsita Putatunda <
ipsita.putatunda at gmail.com> wrote:
> Hi Mary,
> Thanks for your suggestions. I have modified my script as per your
> suggestion, but the issue is LH4 level dimension is in Km unit whereas,
> wscale level unit is in hpa. If I am trying to select the levels same for
> both the variable (say 25 levels for LH4 and for wscale) then both the plot
> is not covering same height.
> Is there any way to solve this isuue? Can I convert my data variable LH4
> from Km to hpa or wscale hpa to Km in ncl?
>
> Thanks,
> Ipsita
>
>
> On Wed, Aug 20, 2014 at 12:27 AM, Mary Haley <haley at ucar.edu> wrote:
>
>> Ipsita,
>>
>> Thanks for providing your code and data.
>>
>> I'm a bit confused by the code, because the "LH4" variable purposely has
>> all the metadata stripped off by this command:
>>
>> LH4=(/L3*24/)
>>
>> You want to preserve metadata, especially coordinate arrays, if you are
>> going to be plotting and/or overlaying variables.
>>
>> LH4=L3
>> LH4=L3*24 ; preserve metadata
>>
>> You also want to do this for "wscale":
>>
>> wscale=W ; Trick for copying metadata
>>
>> wscale=W*scale
>>
>> The above two lines could also be done like this:
>>
>> wscale=W*scale
>> copy_VarMeta(W,wscale) ; Copy all metadata from W to wscale
>>
>> Another issue is you are plotting LH4 using "gsn_contour" instead of
>> "gsn_csm_contour". You want to use "gsn_csm_xxxx" scripts where possible,
>> because they examine your variable to check for metadata, and will use that
>> metadata, including coordinate arrays, to correctly plot it.
>>
>> Even with these corrections, the overlay is not going to work properly
>> because your "lev" coordinate array is different in for your LH4 variable
>> than it is for your wscale/U variables. In order for "overlay" to work,
>> your X/Y coordinate arrays must be in the same data space.
>>
>> For LH4, note that the "lev" values go from 0 to 14:
>>
>> Variable: LH4
>> Type: float
>> Total Size: 164160 bytes
>> 41040 values
>> Number of Dimensions: 2
>> Dimensions and sizes: [lev | 57] x [lon | 720]
>> Coordinates:
>> lev: [ 0.. 14]
>> lon: [-179.75..179.75]
>>
>> For wscale "levels" looks like this:
>>
>> Variable: wscale
>> Type: float
>> Total Size: 72000 bytes
>> 18000 values
>> Number of Dimensions: 2
>> Dimensions and sizes: [levels | 25] x [lon | 720]
>> Coordinates:
>> levels: [1000.. 100]
>> lon: [-180..179.5]
>>
>> Finally, you are calling "draw()", but you need to also call "frame(wks)"
>> after the "draw" command so that the graphic is ended properly.
>>
>> Please fix these issues and post to ncl-talk if you continue to have
>> problems.
>>
>> --Mary
>>
>>
>>
>>
>> On Mon, Aug 18, 2014 at 11:12 PM, Ipsita Putatunda <
>> ipsita.putatunda at gmail.com> wrote:
>>
>>> Hi Mary,
>>> I have tried as per your suggestion to first overlay the plots and
>>> then to attach, but it is not doing as per my requirements. As my data is
>>> from -179 to 179 longitude wise and I want to plot from -30 to -30 that is
>>> why am attaching two plots from -30 to 179 and 179 to -30 longitude. I
>>> finally want to over lay one vector plot and one contour plot. My script
>>> with data files are attached herewith.
>>> Any help will be appreciated.
>>>
>>> Thanks,
>>> Ipsita
>>> GLOBAL_SON.nc
>>> <https://docs.google.com/file/d/0B438RTfd8A-Nc1NXeHNzMHZHekE/edit?usp=drive_web>
>>>
>>> MERRA_regrid.nc
>>> <https://docs.google.com/file/d/0B438RTfd8A-NSGR3XzJGbHo3OHc/edit?usp=drive_web>
>>>
>>>
>>>
>>> On Thu, Aug 14, 2014 at 9:03 PM, Mary Haley <haley at ucar.edu> wrote:
>>>
>>>> Ipsita,
>>>>
>>>> I'm not exactly sure how you want your final plot to look, but the
>>>> "overlay" procedure really is meant to be used to do simply overlays of
>>>> say, contours on a map, or vectors on contours on a map, etc.
>>>>
>>>> It looks like you are trying to attach some plots via X and/or Y axes,
>>>> and then try to use these as overlays, which won't work. The
>>>> gsn_attach_plots (which is perhaps poorly named) is simply meant to join
>>>> several plots together along a given axis.
>>>>
>>>> My suggestion is to overlay the plots *before* you call
>>>> gsn_attach_plots.
>>>>
>>>> If you continue to have problems, please describe your desired result
>>>> in more detail, and what you are currently getting of your script that
>>>> isn't correct.
>>>>
>>>> As always, it helps if you can provide a full script and your data so
>>>> we can run the script here.
>>>>
>>>> Thanks,
>>>>
>>>> --Mary
>>>>
>>>>
>>>>
>>>> On Wed, Aug 13, 2014 at 1:18 PM, Ipsita Putatunda <
>>>> ipsita.putatunda at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>> I want to get an overlay plot of two plots which are created by
>>>>> attached plot. I have tried with overlay function which is not giving my
>>>>> desired plot. I tried with setting vpXF, vpYF for each plot also, but still
>>>>> am not getting overlaid plot. Is attaching plots before overlaying is
>>>>> causing the problem? Plotting part of my script is attached herewith.
>>>>> Please help me to solve this issue.
>>>>>
>>>>> Thanks,
>>>>> Ipsita
>>>>>
>>>>> _______________________________________________
>>>>> ncl-talk mailing list
>>>>> List instructions, subscriber options, unsubscribe:
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>>>>>
>>>>>
>>>>
>>>
>>
>
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