De Pauw Antoine wrote:
> Jeff,
>
> I still don't know how to either remove this artifact or fill my arrays with
> values to remove empty regions, and I'll make a last attempt to resolve it
>
> I uploaded a data file here: http://scqp.ulb.ac.be/20080821.b56
>
> The actual code snippet is here:
> http://snipplr.com/view/8307/map-plotting-python-code-temporary/
>
> I hope you'll be able to reproduce it, I set the cmap to winter for you to
> see the gap... setting it to hot will make the grayish border visible in
> high resolution by zooming it... I think the border (not the empty zone)
> could be an artifact with the hot colormap
>
>
> Antoine De Pauw
> Collaborateur de recherches, Informatique - Research collaborator, IT
> Laboratoire de chimie quantique et photophysique - Quantum chemistry and
> photophysics laboratory
> Université Libre de Bruxelles - ULB
>
>
Antoine: Here is a version that just plots the pixels directly, without
interpolating to a grid. I personally like this better, since you can
easily see where you actually have data.
HTH,
-Jeff
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import matplotlib.mlab as mlab
import numpy as np
import os
fileName = '20080821.b56'
titre='SO2'
legende='Delta Brightness Temperature (K)'
nbreligne=long(os.stat(fileName)[6])/(8*int(fileName[-2:]))
rawfile=np.fromfile(open(fileName,'rb'),'<d',-1)
Lat=rawfile[0:nbreligne]
Lon=rawfile[nbreligne:nbreligne*2]
Val=rawfile[nbreligne*21:nbreligne*22]
map=Basemap(projection='mill',llcrnrlat=-90,urcrnrlat=90,\
urcrnrlon=180,llcrnrlon=-180,resolution='l')
x, y = map(Lon, Lat)
plt.scatter(x,y,s=25,c=Val,marker='s',edgecolor="None",cmap=plt.cm.winter,vmin=-5,vmax=-1.2,
alpha=0.5)
cb=plt.colorbar(shrink=0.6)
cb.ax.set_ylabel(legende,fontsize=11)
for t in cb.ax.get_yticklabels():
t.set_fontsize(7)
meridians = np.arange(-180,180,60)
parallels = np.arange(-90,90,30)
map.drawparallels(parallels,labels=[1,0,0,0],fontsize=7,linewidth=0.25)
map.drawmeridians(meridians,labels=[0,0,0,1],fontsize=7,linewidth=0.25)
map.drawcoastlines(0.25,antialiased=1)
plt.title(titre)
plt.show()
> -----Original Message-----
> From: Jeff Whitaker [mailto:[EMAIL PROTECTED]
> Sent: lundi 22 septembre 2008 13:59
> To: De Pauw Antoine
> Cc: 'John Hunter'; 'Matplotlib Users'
> Subject: Re: [Matplotlib-users] Information request
>
> De Pauw Antoine wrote:
>
>> Jeff,
>>
>> I included here a figure where you'll see the border problem for imshow in
>> my case
>>
>> http://img217.imageshack.us/img217/5240/testfigzp3.png
>>
>> The border wraps at -180 and 180 to form the white line
>>
>> PS: it is atmospheric ice and not SO2, I just omitted to change the title
>>
> ^^
>
>> Antoine De Pauw
>> Collaborateur de recherches, Informatique - Research collaborator, IT
>> Laboratoire de chimie quantique et photophysique - Quantum chemistry and
>> photophysics laboratory
>> Université Libre de Bruxelles - ULB
>>
>>
>
> Antoine: I hate to keep repeating myself - but we can't do much if you
> don't provide a self-contained script, that I can run, which reproduces
> the problem. My guess is that the line along the dateline, and the
> point at the South Pole are missing values (which griddata set to
> missing because they are outside the extent of the data) - but that's
> just a guess until I can reproduce it.
>
> -Jeff
>
>> -----Original Message-----
>> From: Antoine De Pauw [mailto:[EMAIL PROTECTED]
>> Sent: jeudi 18 septembre 2008 17:23
>> To: Jeff Whitaker; [EMAIL PROTECTED]
>> Cc: 'John Hunter'; 'Matplotlib Users'
>> Subject: re:Re: [Matplotlib-users] Information request
>>
>> Jeff,
>>
>> No the example doesn't show that line
>>
>> If I reduce the amount of data, the border will be on every side of the
>>
> plot
>
>> I'll show you an orthographic plot with no maskinf tomorrow and you will
>>
> see
>
>> the problem easily, it wraps in a white line along the 0° meridian and a
>> white circle in the pole
>>
>> I think it's the imshow layer that is not totally transparent on the map
>> background.. I tried every trick I could for example to put some
>>
> zero-valued
>
>> points on each corner to make imshow interpolate correctly the sides, but
>> that doesn't make any difference
>>
>>
>>
>>> De Pauw Antoine wrote:
>>>
>>>
>>>> Jeff,
>>>>
>>>> Yes they disappear, and they fluctuate with the interpolation method
>>>>
> used
>
>>>> For example, nearest interpolation don't show the line
>>>>
>>>> Also, if I reduce the grid resolution, the line is thicker, and if I use
>>>>
>>>>
>> a
>>
>>
>>>> masked array to get rid of undesired values, the border shows really
>>>> strongly
>>>>
>>>> Here's an example everyone will see:
>>>>
>>>> http://img225.imageshack.us/img225/2671/testfigep2.png
>>>>
>>>> (everything except the clouds is noise)
>>>>
>>>> Antoine De Pauw
>>>> Collaborateur de recherches, Informatique - Research collaborator, IT
>>>> Laboratoire de chimie quantique et photophysique - Quantum chemistry and
>>>> photophysics laboratory
>>>> Université Libre de Bruxelles - ULB
>>>>
>>>>
>>>>
>>> Antoine: Sorry to seem dense, but I don't see anything wrong with that
>>> plot. I see a white border along the north and south pole, but I
>>> intrepret that to be missing values. However, my eyes are notoriously
>>> bad. I'd like to be to run a script that generates the artifacts
>>> myself, so I can zoom in and see the problem myself. Does the
>>> griddata_demo.py script show the same problem for you?
>>>
>>> -Jeff
>>>
>>>
>>>> -----Original Message-----
>>>> From: Jeff Whitaker [mailto:[EMAIL PROTECTED]
>>>> Sent: mercredi 17 septembre 2008 19:05
>>>> To: John Hunter
>>>> Cc: De Pauw Antoine; Matplotlib Users
>>>> Subject: Re: [Matplotlib-users] Information request
>>>>
>>>> John Hunter wrote:
>>>>
>>>>
>>>>
>>>>> On Wed, Sep 17, 2008 at 11:54 AM, John Hunter <[EMAIL PROTECTED]>
>>>>>
> wrote:
>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Attached is a screenshot (zoom.png) from the gimp, zoomed in near the
>>>>>> axes border. The black horizontal line is the top axes border, the
>>>>>> horizontal grey line is the artifact, the vertical dashed line is a
>>>>>> grid line. I don't know if this offers a clue, but if you look at a
>>>>>> zoom in the upper right corner, the grey line seems to break up and
>>>>>> curve down and to the right (corner.png)
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> Sorry, screwed up corner.png (I attached the original and not the
>>>>> screenshot). The correct screenshot is attached
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>> John: OK, now I finally see it. Antoine: Do these artifacts
>>>> disappear if you comment out the imshow call?
>>>>
>>>> -Jeff
>>>>
>>>>
>>>>
>>>>
>>> --
>>> Jeffrey S. Whitaker Phone : (303)497-6313
>>> Meteorologist FAX : (303)497-6449
>>> NOAA/OAR/PSD R/PSD1 Email : [EMAIL PROTECTED]
>>> 325 Broadway Office : Skaggs Research Cntr 1D-113
>>> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
--
Jeffrey S. Whitaker Phone : (303)497-6313
Meteorologist FAX : (303)497-6449
NOAA/OAR/PSD R/PSD1 Email : [EMAIL PROTECTED]
325 Broadway Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
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