Re: gsn_csm_pres_hgt for 1D data?

Thank you, Mary.

I was stuck by this function again. Could you tell me how to switch the
y-axes when I use gsn_csm_pres_hgt? For example, by default, the left
y-axis uses pressure coordinate and the right uses height coordinate. Is
there a simple way to have height on the left and pressure on the right?

-Sha

On Tue, Apr 29, 2014 at 11:58 AM, Mary Haley <haley@ucar.edu> wrote:

> Sha,
>
> I'm responding back to ncl-talk, because we prefer that follow-up
> questions always go back to the list, and not to individual developers.
>
> This particular function uses an internal function to calculate the height
> based on pressure. Since this calculation depends on coordinate arrays,
> this function then only allows 2D data that is represented by coordinate
> arrays. The function is called "gsn_geop_hgt", and you can see it inside
> the $NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl script.
>
> Once you start trying put 1D unstructured data on a plot, you will lose
> your tickmarks, unless you are putting the data over a map, which you are
> not doing.
>
> To use gsn_csm_pres_hgt, you will need to regrid your data to a
> rectilinear grid (e.g. one with coordinate arrays).
>
> Otherwise, you can use gsn_csm_contour to create the contours, which will
> cause your tickmarks to disappear. You can then overlay this contour plot
> on a "linear" plot to force the tickmarks to reappear, and then you can use
> tmYRMode/tmYRValues/tmYRLabels to label the right Y axis with height
> values. The problem is, you will need to provide the appropriate height
> values, given the pressure values.
>
> You can see an example of overlaying a contour plot on a linear plot at:
>
> http://www.ncl.ucar.edu/Applications/2Dvertcoord.shtml
>
> Look at the first example on this page.
>
> --Mary
>
> On Apr 28, 2014, at 6:39 PM, Sha Feng <sfeng@mail.usf.edu> wrote:
>
> > Hi Mary,
> >
> > May I ask what the relationship (equation) ncl uses for gsn_csm_pres_hgt
> to generate the height coordinate?
> >
> > I need to plot a vertical profile with pressure and height coordinates,
> so I am thinking to take advantage of this function. But it only works for
> 2d data. Could you please inform?
> >
> > Thanks,
> > Sha
>
>

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Received on Wed Apr 30 16:56:15 2014