Thanks for responding. I believe quiver is more appropriate because I am
only using wind direction (at this stage) and this results in arrows.
I have had a look at the demos and still do not understand how to plot my
degrees in arrows. How do I define which angle is north, south, west, east,
etc?
Any suggestions? Thanks
from netCDF4 import Dataset
import numpy as N
import pylab as plt
from numpy import ma as MA
from mpl_toolkits.basemap import Basemap
import os
ncfile=Dataset('E:/temp_winddir/IDZ00026_VIC_ADFD_Wind_Dir_SFC.nc', 'r+',
'NETCDF4')
WDIR=ncfile.variables['Wind_Dir_SFC'][-50]
LAT=ncfile.variables['latitude'][:]
LON=ncfile.variables['longitude'][:]
TIME=ncfile.variables['time'][-50]
ncfile.close()
map = Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
x,y=LON,LAT
u=10*x
v=10*y
map.quiver(x,y,u, v, WDIR)
plt.title('Wind Direction')
plt.show()
Traceback (most recent call last):
File "d:/plot_winddirection.py", line 22, in <module>
map.quiver(x,y,u, v, WDIR)
File "C:\Python27\lib\site-packages\mpl_toolkits\basemap\__init__.py",
line 3102, in quiver
ret = ax.quiver(x,y,u,v,*args,**kwargs)
File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 6320, in
quiver
q = mquiver.Quiver(self, *args, **kw)
File "C:\Python27\lib\site-packages\matplotlib\quiver.py", line 395, in
__init__
self.XY = np.hstack((X[:,np.newaxis], Y[:,np.newaxis]))
File "C:\Python27\lib\site-packages\numpy\core\shape_base.py", line 270,
in hstack
return _nx.concatenate(map(atleast_1d,tup),1)
ValueError: array dimensions must agree except for d_0
On Tue, Oct 4, 2011 at 12:54 PM, Eric Firing <efir...@hawaii.edu> wrote:
> On 10/03/2011 03:00 PM, Benjamin Root wrote:
> > On Mon, Oct 3, 2011 at 6:51 PM, questions anon <questions.a...@gmail.com
> > <mailto:questions.a...@gmail.com>> wrote:
> >
> > Hi All,
> > Is there a simple way to plot a directional arrow to represent a
> degree?
> > I have a netcdf file containing wind direction as degrees and I
> > would like to make a plot with all little arrows representing the
> > wind direction.
> > Below is the code I am using currently to plot wind direction but am
> > not sure where/how to add directional arrows.
> > Thanks
> >
> >
> > from netCDF4 import Dataset
> > import numpy as N
> > import pylab as plt
> > from numpy import ma as MA
> > from mpl_toolkits.basemap import Basemap
> > import os
> >
> > ncfile=Dataset('E:/WINDDIR/IDZ00026_VIC_ADFD_Wind_Dir_SFC.nc', 'r+',
> > 'NETCDF4')
> > WDIR=ncfile.variables['Wind_Dir_SFC'][-50]
> > LAT=ncfile.variables['latitude'][:]
> > LON=ncfile.variables['longitude'][:]
> > TIME=ncfile.variables['time'][-50]
> > fillvalue=ncfile.variables['Wind_Dir_SFC']._FillValue
> > WDIR=MA.masked_values(WDIR, fillvalue)
> > ncfile.close()
> >
> > map = Basemap(projection='merc',llcrnrlat=-40,urcrnrlat=-33,
> >
> llcrnrlon=139.0,urcrnrlon=151.0,lat_ts=0,resolution='i')
> > x,y=map(*N.meshgrid(LON,LAT))
> > map.drawstates()
> > map.drawcoastlines()
> > plt.title('Wind Direction')
> > CS = map.contourf(x,y,WDIR,15, cmap=plt.cm.jet)
> > l,b,w,h =0.1,0.1,0.8,0.8
> > cax = plt.axes([l+w+0.025, b, 0.025, h])
> > plt.colorbar(CS,cax=cax,drawedges=True)
> > plt.savefig((os.path.join('E:/WINDDIR/', 'WDIRSFC.png')))
> > plt.show()
> >
> >
> > Would the barb() command do what you want?
> >
> >
> http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.barbs
> > http://matplotlib.sourceforge.net/examples/pylab_examples/barb_demo.html
> >
> > They aren't arrows, but they are commonly used in meteorology to plot
> > windfields.
> >
> > Cheers,
> > Ben Root
>
> There is also quiver, both in matplotlib and in basemap. See the
> quiver_demo.py and barb_demo.py in the basemap examples directory.
>
> Eric
>
> >
> >
> >
> >
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> >
> >
> >
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>
>
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> definitive record of customers, application performance, security
> threats, fraudulent activity and more. Splunk takes this data and makes
> sense of it. Business sense. IT sense. Common sense.
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All the data continuously generated in your IT infrastructure contains a
definitive record of customers, application performance, security
threats, fraudulent activity and more. Splunk takes this data and makes
sense of it. Business sense. IT sense. Common sense.
http://p.sf.net/sfu/splunk-d2dcopy1
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