That's what was happening! Thanks again Jeff!
________________________________
From: Jeff Whitaker <jsw...@fastmail.fm>
To: antonv <vasilescu_an...@yahoo.com>
Cc: matplotlib-users@lists.sourceforge.net
Sent: Tuesday, April 14, 2009 4:39:13 AM
Subject: Re: [Matplotlib-users] basemap error or user error?
antonv wrote:
> Jeff, thanks for the comment on rebuilding the lons and lats!
>
> I have attached 2 images, one that is from the whole data in the file and
> the other the zoomed version.
> http://www.nabble.com/file/p23031035/basemap_all.png basemap_all.png
> http://www.nabble.com/file/p23031035/basemap_zoom.png basemap_zoom.png
> What seems to be happening is that the coordinates seem to be in different
> projections as the values of lats.min(),lons.min(),lats.max(),lons.max() are
> 25.0,210.0,50.0,250.0 while the list I'm providing is
> 32.35,-121.0,34.75,-116.75.
Anton: Try using (32.35, 239,34.75,243.25). The longitudes in your data
probably go from 0 to 360, so negative longitudes are outside the region
spanned by your data.
-Jeff
> Any ideas on why basemap seems to be reading
> both coordinate lists and provides the proper land contours while contourf
> seems to be off?
>
> Thanks,
> Anton
>
>
>
>
>
>
> Jeff Whitaker wrote:
>
>> antonv wrote:
>>
>>> Hi all,
>>>
>>> I have a weird thing happening with basemap and I am not sure if it's
>>> basemap or me, but more than likely it's me :(
>>>
>>> Here is the grib file that I am using:
>>> http://downloads.75ive.com/multi_1.20090321.t18z_multi_1.wc_10m.all.grb2
>>> http://downloads.75ive.com/multi_1.20090321.t18z_multi_1.wc_10m.all.grb2
>>> And here is my code:
>>> #############################################
>>> import matplotlib
>>> import matplotlib.mpl as mpl
>>> import matplotlib.pyplot as plt
>>> import matplotlib.mlab as mlab
>>> import numpy as np
>>> import matplotlib.pylab as pylab
>>> from mpl_toolkits.basemap import Basemap
>>> from grib2 import Grib2Decode
>>>
>>> grbs = Grib2Decode('multi_1.20090321.t18z_multi_1.wc_10m.all.grb2')
>>>
>>> lats, lons = grbs[0].grid()
>>> mapCoords = [32.35,-121.0,34.75,-116.75]
>>> #mapCoords = [lats.min(),lons.min(),lats.max(),lons.max()]
>>>
>>> colorList =
>>> [[0.,0.,205./255.],[0,102./255.,255./255.],[0,183./255.,255./255.],[0,224./255.,255./255.],
>>>
>>> [0,255./255.,255./255.],[0,255./255.,204./255.],[0,255./255.,153./255.],[0,255./255.,0],
>>>
>>> [153./255.,255./255.,0],[204./255.,255./255.,0],[255./255.,255./255.,0],[255./255.,204./255.,0],
>>>
>>> [255./255.,153./255.,0],[255./255.,102./255.,0],[255./255.,0,0],[176./255.,48./255.,96./255.],
>>> [208./255.,32./255.,144./255.],[255./255.,0,255./255.]]
>>> cmap = matplotlib.colors.ListedColormap(colorList, name = 'theColorMap',
>>> N =
>>> len(colorList))
>>>
>>> m = Basemap(projection='merc',lat_ts = 30,\
>>>
>>> llcrnrlat=mapCoords[0],llcrnrlon=mapCoords[1],urcrnrlat=mapCoords[2],urcrnrlon=mapCoords[3],\
>>> resolution='h',area_thresh=0.5, suppress_ticks = True)
>>>
>>> fig = plt.figure(figsize=(14.58,10.58))
>>> fig.set_dpi(100)
>>>
>>> nlats, nlons = grbs[0].data().shape
>>>
>>> x = np.linspace(lons.min(),lons.max(),nlons)
>>> y = np.linspace(lats.min(),lats.max(),nlats)
>>>
>>> X, Y = m(*np.meshgrid(x, y))
>>>
>>> z = grbs[0].data().filled(1)
>>>
>>> m.contourf(X,Y,z,cmap=cmap,levels=[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19],extend='both')
>>>
>>> m.fillcontinents(color='green',lake_color='b')
>>> m.drawcoastlines(color='k', linewidth=0.75)
>>> m.drawcountries(color='k', linewidth=0.25)
>>> m.drawstates(color='k', linewidth=0.25)
>>> m.drawmapboundary(linewidth=1.0, color='k')
>>>
>>> plt.show()
>>> #############################################
>>>
>>> If you look at lines 14 and 15 you can see that i have a variable called
>>> mapCoords that feeds the lat/lon coordinates to the basemap object. If i
>>> set
>>> them up using the commented line (line 15) it will plot the map for all
>>> the
>>> data in the file and it will display it correctly. If i use line 14 which
>>> is
>>> the zoomed area that i am interested in it will display the basemap map
>>> correctly zoomed in but it will not show the plotted data. Any ideas on
>>> what
>>> is happening here?
>>>
>>> Also, if you have any comments on optimizing the code I would really
>>> appreciate it!
>>>
>>> Thanks,
>>> Anton
>>>
>>>
>> Anton: Probably your data doesn't cover the zoomed region, but without
>> actually having your data I can't be sure.
>> One question: why are you rebuilding the lons and lats from scratch when
>> you already have them? It seems like you can get rid of
>>
>> nlats, nlons = grbs[0].data().shape
>> x = np.linspace(lons.min(),lons.max(),nlons)
>> y = np.linspace(lats.min(),lats.max(),nlats)
>> X, Y = m(*np.meshgrid(x, y))
>>
>> and replace it with
>>
>> X,Y = m(lons, lats)
>>
>>
>> -Jeff
>>
>> -- Jeffrey S. Whitaker Phone : (303)497-6313
>> Meteorologist FAX : (303)497-6449
>> NOAA/OAR/PSD R/PSD1 Email : jeffrey.s.whita...@noaa.gov
>> 325 Broadway Office : Skaggs Research Cntr 1D-113
>> Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
>>
>>
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>
>
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