Merge branch 'master' of https://github.com/matplotlib/basemap

Author: Jeff Whitaker

doc/users/examples.rst

@@ -31,7 +31,9 @@ associated with the Basemap.
 For more specifics of how to use the Basemap instance methods,
 see :ref:`api-index`.
 
-Here are the examples:
+Here are the examples (many of which utilize the 
+`netcdf4-python <http://netcdf4-python.googlecode.com>`__ module
+to retrieve datasets over http):
 
 * Plot contour lines on a basemap
 
@@ -77,3 +79,23 @@ Here are the examples:
 .. literalinclude:: figures/plotsst.py
 
 .. image:: figures/plotsst.png
+
+* Plotting wind vectors and wind barbs.
+
+.. literalinclude:: figures/plotwindvec.py
+ 
+.. image:: figures/plotwindvec1.png
+
+.. image:: figures/plotwindvec2.png
+
+* Draw great circle between NY and London.
+
+.. literalinclude:: figures/plotgreatcircle.py
+ 
+.. image:: figures/plotgreatcircle.png
+
+* Draw day-night terminator on a map.
+
+.. literalinclude:: figures/plotdaynight.py
+ 
+.. image:: figures/plotdaynight.png

doc/users/figures/plotdaynight.py

@@ -0,0 +1,19 @@
+import numpy as np
+from mpl_toolkits.basemap import Basemap
+import matplotlib.pyplot as plt
+from datetime import datetime
+# miller projection 
+map = Basemap(projection='mill',lon_0=180)
+# plot coastlines, draw label meridians and parallels.
+map.drawcoastlines()
+map.drawparallels(np.arange(-90,90,30),labels=[1,0,0,0])
+map.drawmeridians(np.arange(map.lonmin,map.lonmax+30,60),labels=[0,0,0,1])
+# fill continents 'coral' (with zorder=0), color wet areas 'aqua'
+map.drawmapboundary(fill_color='aqua')
+map.fillcontinents(color='coral',lake_color='aqua')
+# shade the night areas, with alpha transparency so the 
+# map shows through. Use current time in UTC.
+date = datetime.utcnow()
+CS=map.nightshade(date)
+plt.title('Day/Night Map for %s (UTC)' % date.strftime("%d %b %Y %H:%M:%S"))
+plt.savefig('plotdaynight.png')

doc/users/figures/plotgreatcircle.py

@@ -0,0 +1,25 @@
+from mpl_toolkits.basemap import Basemap
+import numpy as np
+import matplotlib.pyplot as plt
+# create new figure, axes instances.
+fig=plt.figure()
+ax=fig.add_axes([0.1,0.1,0.8,0.8])
+# setup mercator map projection.
+m = Basemap(llcrnrlon=-100.,llcrnrlat=20.,urcrnrlon=20.,urcrnrlat=60.,\
+            rsphere=(6378137.00,6356752.3142),\
+            resolution='l',projection='merc',\
+            lat_0=40.,lon_0=-20.,lat_ts=20.)
+# nylat, nylon are lat/lon of New York
+nylat = 40.78; nylon = -73.98
+# lonlat, lonlon are lat/lon of London.
+lonlat = 51.53; lonlon = 0.08
+# draw great circle route between NY and London
+m.drawgreatcircle(nylon,nylat,lonlon,lonlat,linewidth=2,color='b')
+m.drawcoastlines()
+m.fillcontinents()
+# draw parallels
+m.drawparallels(np.arange(10,90,20),labels=[1,1,0,1])
+# draw meridians
+m.drawmeridians(np.arange(-180,180,30),labels=[1,1,0,1])
+ax.set_title('Great Circle from New York to London')
+plt.savefig('plotgreatcircle.png')

doc/users/figures/plotwindvec.py

@@ -0,0 +1,95 @@
+import numpy as np
+import matplotlib.pyplot as plt
+import datetime
+from mpl_toolkits.basemap import Basemap, shiftgrid
+from netCDF4 import Dataset, date2index, num2date
+from mpl_toolkits.axes_grid1 import make_axes_locatable
+# specify date to plot.
+date = datetime.datetime(1993,3,14,0)
+# set OpenDAP server URL.
+URL="http://nomad1.ncep.noaa.gov:9090/dods/reanalyses/reanalysis-2/6hr/pgb/pgb"
+data = Dataset(URL)
+# read lats,lons,times.
+latitudes = data.variables['lat'][:]
+longitudes = data.variables['lon'][:].tolist()
+times = data.variables['time']
+# get time index for desired date.
+ntime = date2index(date,times,calendar='standard')
+# get sea level pressure and 10-m wind data.
+slpdata = data.variables['presmsl']
+udata = data.variables['ugrdprs']
+vdata = data.variables['vgrdprs']
+# mult slp by 0.01 to put in units of hPa.
+slpin = 0.01*slpdata[ntime,:,:]
+uin = udata[ntime,0,:,:] 
+vin = vdata[ntime,0,:,:] 
+# add cyclic points manually (could use addcyclic function)
+slp = np.zeros((slpin.shape[0],slpin.shape[1]+1),np.float)
+slp[:,0:-1] = slpin; slp[:,-1] = slpin[:,0]
+u = np.zeros((uin.shape[0],uin.shape[1]+1),np.float64)
+u[:,0:-1] = uin; u[:,-1] = uin[:,0]
+v = np.zeros((vin.shape[0],vin.shape[1]+1),np.float64)
+v[:,0:-1] = vin; v[:,-1] = vin[:,0]
+longitudes.append(360.); longitudes = np.array(longitudes)
+# make 2-d grid of lons, lats
+lons, lats = np.meshgrid(longitudes,latitudes)
+# make orthographic basemap.
+m = Basemap(resolution='c',projection='ortho',lat_0=60.,lon_0=-60.)
+# create figure, add axes
+fig1 = plt.figure(figsize=(8,10))
+ax = fig1.add_axes([0.1,0.1,0.8,0.8])
+# set desired contour levels.
+clevs = np.arange(960,1061,5)
+# compute native x,y coordinates of grid.
+x, y = m(lons, lats)
+# define parallels and meridians to draw.
+parallels = np.arange(-80.,90,20.)
+meridians = np.arange(0.,360.,20.)
+# plot SLP contours.
+CS1 = m.contour(x,y,slp,clevs,linewidths=0.5,colors='k',animated=True)
+CS2 = m.contourf(x,y,slp,clevs,cmap=plt.cm.RdBu_r,animated=True)
+# plot wind vectors on projection grid.
+# first, shift grid so it goes from -180 to 180 (instead of 0 to 360
+# in longitude).  Otherwise, interpolation is messed up.
+ugrid,newlons = shiftgrid(180.,u,longitudes,start=False)
+vgrid,newlons = shiftgrid(180.,v,longitudes,start=False)
+# transform vectors to projection grid.
+uproj,vproj,xx,yy = \
+m.transform_vector(ugrid,vgrid,newlons,latitudes,31,31,returnxy=True,masked=True)
+# now plot.
+Q = m.quiver(xx,yy,uproj,vproj,scale=700)
+# make quiver key.
+qk = plt.quiverkey(Q, 0.1, 0.1, 20, '20 m/s', labelpos='W')
+# draw coastlines, parallels, meridians.
+m.drawcoastlines(linewidth=1.5)
+m.drawparallels(parallels)
+m.drawmeridians(meridians)
+# use axes_grid toolkit to make colorbar axes.
+divider = make_axes_locatable(ax)
+cax = divider.append_axes("bottom", size="5%", pad=0.1)
+cb = plt.colorbar(CS2,orientation='horizontal',cax=cax)
+cb.set_label('hPa')
+# set plot title
+ax.set_title('SLP and Wind Vectors '+str(date))
+fig1.savefig('plotwindvec1.png')
+
+# create 2nd figure, add axes
+fig2 = plt.figure(figsize=(8,10))
+ax = fig2.add_axes([0.1,0.1,0.8,0.8])
+# plot SLP contours
+CS1 = m.contour(x,y,slp,clevs,linewidths=0.5,colors='k',animated=True)
+CS2 = m.contourf(x,y,slp,clevs,cmap=plt.cm.RdBu_r,animated=True)
+# plot wind barbs over map.
+barbs = m.barbs(xx,yy,uproj,vproj,length=5,barbcolor='k',flagcolor='r',linewidth=0.5)
+# draw coastlines, parallels, meridians.
+m.drawcoastlines(linewidth=1.5)
+m.drawparallels(parallels)
+m.drawmeridians(meridians)
+# use axes_grid toolkit to make colorbar axes.
+divider = make_axes_locatable(ax)
+cax = divider.append_axes("bottom", size="5%", pad=0.1)
+cb = plt.colorbar(CS2,orientation='horizontal',cax=cax)
+cb.set_label('hPa')
+# set plot title.
+ax.set_title('SLP and Wind Barbs '+str(date))
+fig2.savefig('plotwindvec2.png')