Re: overlay different maps

On Wed, 22 Aug 2007 turuncu_at_be.itu.edu.tr wrote:

> hi Mary,
>
> thanks for you help. ok, i try to define the problem much more clearly,
>
> i have two different data set which is in different non-uniform grid (the
> lat and lon values is in 2d array). You can think that there are two
> different nested atmospheric model domain and i want to plot terrain
> height data for them in same plot.
>
> Each of the data is in different resolution, so same plot must be contain
> each one of the domain data. The finer domain data must be overlay into
> coarser one. I write following code to do this after posting mail to list,
>
> ...
> ...
> res.tfDoNDCOverlay = True
> ...
> ...
> ## first domain plot
> dims = m1t.shape
> r = m1t.rank
> r1 = dims[r-1]
> r2 = dims[r-2]
> res.mpLeftCornerLatF = float(m1lat[0][r1-1])
> res.mpLeftCornerLonF = float(m1lon[0][r1-1])
> res.mpRightCornerLatF = float(m1lat[r2-1][0])
> res.mpRightCornerLonF = float(m1lon[r2-1][0])
> plot1 = Ngl.contour_map(wks, transpose(m1t[0]), res)
>
> ## second domain plot
> res2 = Ngl.Resources()
> list = Ngl.crt_dict(res)
> for key in list.keys():
> if (key[0:2] == 'cn' or key[0:2] == 'sf' or key[0:3] == 'ngl'):
> setattr(res2,key,list[key])
>
> m2lon = m2.variables["lon"]
> m2lat = m2.variables["lat"]
> dims = m2t.shape
> r2 = m2t.rank
> r21 = dims[r-1]
> r22 = dims[r-2]
> res2.sfYArray = m2lat[0,:]
> res2.sfXArray = m2lon[:,0]
> plot2 = Ngl.contour(wks, transpose(m2t[0]), res2)
> Ngl.overlay(plot1, plot2)
>
> in this script m1lon and m1lat represents the domain 1 data and m2lat and
> m2lon for domain2. I don't use the overlay for two Ngl.contor_map plot as
> you know. For this reason i try to define sfXArray and sfYArray but in
> this case lat and lon values is in 2 dimensional array and i could not
> give the positions of the grids correctly. as a result, inner plot is not
> fit into second one.
>
> You can find sample plot in,
>
> http://kullanici.be.itu.edu.tr/~turuncu/terrain.ps
>
> so, i hope this help you.
>
> best regards,
>
> ufuk

Hi again Ufuk,

It looks to me like you are doing the right thing with the first
plot. By seting tfDoNDCOverlay to True, this means that your data was
already projected onto the map, and as long as you get the map
parameters correct, your contour plot should overlay just fine on the
map. From the image you attached, it looks like this part is correct.

Then, I assume by "inner plot" you mean the one associated with the
m2t data? If so, I'm curious about the code:

res2.sfYArray = m2lat[0,:]
res2.sfXArray = m2lon[:,0]

Are m2lat and m2lon two-dimensional (2D) arrays that are the same size
as m2t[0]? If so, is there any reason you can't use the full arrays,
rather than subsetting them? You should be able to contour data that
has 2D lat/lon arrays, as long as the 2D lat/lon arrays are fairly
regular. Your code would then look like this:

res2.sfYArray = m2lat
res2.sfXArray = m2lon

If this gives you an error message, then please let me know what the
exact message is. Also, if we need to look into this further, it
might be helpful if we can get access to your code and data so we can
run it here.

Thanks,

>>> hi,
>>>
>>> is it possible to overlay to different contour_map plot? generic overlay
>>> function does not allow this kind of plot.
>>>
>>> best regards,
>>>
>>> ufuk utku turuncoglu
>>
>>>
>>
>> Hi Ufuk,
>>
>> I'm not sure what you mean by "different contour_map plot". I believe
>> once you've overlaid an object on another one, you can't then overlay
>> it on different one. You will need to recreate it.
>>
>> That is, if you have something like this:
>>
>> map1 = Ngl.map(wks,res1)
>> map2 = Ngl.map(wks,res2)
>> contour = Ngl.contour(wks,t,cnres)
>> Ngl.overlay(map1,contour)
>>
>> You can't then do this:
>>
>> Ngl.overlay(map2,contour)
>>
>> as you will get an error:
>>
>> fatal:NhlAddOverlay: tranform is already an annotation or overlay: 84
>>
>> You will instead need to do this:
>>
>> map1 = Ngl.map(wks,res1)
>> map2 = Ngl.map(wks,res2)
>> contour1 = Ngl.contour(wks,t,cnres) ; contour1 and contour2
>> contour2 = Ngl.contour(wks,t,cnres) ; are identical
>> Ngl.overlay(map1,contour1)
>> Ngl.overlay(map2,contour2)
>>
>> Some more background: when you call Ngl.contour_map, what's returned
>> is effectively the id for the map plot. Since you can't overlay one
>> map on another map, you can't overlay two Ngl.contour_maps on each
>> other.
>>
>> You don't really need to generate the map multiple times anyway. What
>> you want to do is generate a map plot once, with a call to something
>> like Ngl.contour_map or Ngl.map, and then generate the second plot you
>> want to overlay with a call to something like Ngl.contour.
>>
>> Please see the "overlay1.py" example at:
>>
>> http://www.pyngl.ucar.edu/Examples/gallery.shtml
>>
>> In this script you will see the code:
>>
>> map_plot = Ngl.map(wks,mpres)
>> vector_plot = Ngl.vector(wks,ua,va,vcres)
>> line_contour_plot = Ngl.contour(wks,pa,clres)
>> fill_contour_plot = Ngl.contour(wks,ta,cfres)
>> #
>> # Overlay everything on the map plot.
>> #
>> Ngl.overlay(map_plot,fill_contour_plot)
>> Ngl.overlay(map_plot,line_contour_plot)
>> Ngl.overlay(map_plot,vector_plot)
>>
>> Note that the map_plot is being used as the base for all of the
>> overlays. This is necessary when you do overlays involving a map.
>>
>> --Mary
>>
>>
>> On Wed, 22 Aug 2007, [BE] Ufuk Utku Turuncoglu wrote:
>>
>
>
>
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Received on Thu Aug 23 2007 - 10:35:46 MDT