import numpy as np import matplotlib.pyplot as plt from matplotlib.colors import rgb2hex from mpl_toolkits.basemap import Basemap from numpy.random import uniform # Plot a bunch of randomly distributed points on the earth. # set up stereographic map centered on N. Pole. m = Basemap(lon_0=-105,boundinglat=30., resolution='l',area_thresh=10000.,projection='npstere') # number of points to plot. npts = 500 # generate random points on a sphere, # so that every small area on the sphere is expected # to have the same number of points. # http://mathworld.wolfram.com/SpherePointPicking.html u = uniform(0.,1.,size=npts) v = uniform(0.,1.,size=npts) lons = 360.*u lats = (180./np.pi)*np.arccos(2*v-1) - 90. z = uniform(0,100,size=npts) # this field controls color of dots. # transform lons and lats to map coordinates. x,y = m(lons,lats) # plot them as filled circles on the map. # first, create a figure. fig=plt.figure() # draw colored markers. # use zorder=10 to make sure markers are drawn last. # (otherwise they are covered up when continents are filled) m.scatter(x,y,25,z,cmap=plt.cm.jet,marker='o',edgecolors='none',zorder=10) # plot colorbar for markers. plt.colorbar() # create a list of strings containing z values # or, plot actual numbers as color-coded text strings. #zn = [ '%2i' % zz for zz in z ] ## plot numbers on map, colored by value. #for numstr,zval,xpt,ypt in zip(zn,z,x,y): # # only plot values inside map region. # if xpt > m.xmin and xpt < m.xmax and ypt > m.ymin and ypt < m.ymax: # hexcolor = rgb2hex(plt.cm.jet(zval/100.)[:3]) # plt.text(xpt,ypt,numstr,fontsize=9,weight='bold',color=hexcolor) # draw coasts and fill continents/lakes. m.drawcoastlines(linewidth=0.5) m.fillcontinents(color='coral',lake_color='aqua') # color ocean areas m.drawmapboundary(fill_color='aqua') # draw parallels and meridians. delat = 20. circles = np.arange(0.,90.,delat).tolist()+\ np.arange(-delat,-90,-delat).tolist() m.drawparallels(circles) delon = 45. meridians = np.arange(0,360,delon) m.drawmeridians(meridians,labels=[1,0,1,1]) plt.title('Random Points',y=1.05) plt.show()