Added triangular grid plotting and contouring functions.

svn path=/trunk/matplotlib/; revision=8316

Author: ianthomas23

boilerplate.py

@@ -89,6 +89,10 @@ def %(func)s(%(argspec)s):
     #'spy',
     'stem',
     'step',
+    'tricontour',
+    'tricontourf',
+    'tripcolor',
+    'triplot',
     'vlines',
     'xcorr',
     'barbs',
@@ -117,6 +121,9 @@ def %(func)s(%(argspec)s):
     #'spy'    :  'sci(%(ret)s)',  ### may return image or Line2D
     'quiver' :  'sci(%(ret)s)',
     'specgram'  : 'sci(%(ret)s[-1])',
+    'tricontour' : 'if %(ret)s._A is not None: sci(%(ret)s)',
+    'tricontourf': 'if %(ret)s._A is not None: sci(%(ret)s)',
+    'tripcolor'  : 'sci(%(ret)s)',
 
 }
 

examples/misc/contour_manual.py

@@ -0,0 +1,50 @@
+"""
+Example of displaying your own contour lines and polygons using ContourSet.
+"""
+import matplotlib.pyplot as plt
+from matplotlib.contour import ContourSet
+import matplotlib.cm as cm
+
+# Contour lines for each level are a list/tuple of polygons.
+lines0 = [ [[0,0],[0,4]] ]
+lines1 = [ [[2,0],[1,2],[1,3]] ]
+lines2 = [ [[3,0],[3,2]], [[3,3],[3,4]] ]  # Note two lines.
+
+# Filled contours between two levels are also a list/tuple of polygons.
+# Points can be ordered clockwise or anticlockwise.
+filled01 = [ [[0,0],[0,4],[1,3],[1,2],[2,0]] ]
+filled12 = [ [[2,0],[3,0],[3,2],[1,3],[1,2]],   # Note two polygons.
+             [[1,4],[3,4],[3,3]] ]
+
+
+plt.figure()
+
+# Filled contours using filled=True.
+cs = ContourSet(plt.gca(), [0,1,2], [filled01, filled12], filled=True, cmap=cm.bone)
+cbar = plt.colorbar(cs)
+
+# Contour lines (non-filled).
+lines = ContourSet(plt.gca(), [0,1,2], [lines0, lines1, lines2], cmap=cm.cool,
+                   linewidths=3)
+cbar.add_lines(lines)
+
+plt.axis([-0.5, 3.5, -0.5, 4.5])
+plt.title('User-specified contours')
+
+
+
+# Multiple filled contour lines can be specified in a single list of polygon
+# vertices along with a list of vertex kinds (code types) as described in the
+# Path class.  This is particularly useful for polygons with holes.
+# Here a code type of 1 is a MOVETO, and 2 is a LINETO.
+
+plt.figure()
+filled01 = [ [[0,0],[3,0],[3,3],[0,3],[1,1],[1,2],[2,2],[2,1]] ]
+kinds01  = [ [1,2,2,2,1,2,2,2] ]
+cs = ContourSet(plt.gca(), [0,1], [filled01], [kinds01], filled=True)
+cbar = plt.colorbar(cs)
+
+plt.axis([-0.5, 3.5, -0.5, 3.5])
+plt.title('User specified filled contours with holes')
+
+plt.show()

examples/pylab_examples/tricontour_demo.py

@@ -0,0 +1,98 @@
+"""
+Contour plots of unstructured triangular grids.
+"""
+import matplotlib.pyplot as plt
+import matplotlib.tri as tri
+import numpy as np
+import math
+
+# Creating a Triangulation without specifying the triangles results in the
+# Delaunay triangulation of the points.
+
+# First create the x and y coordinates of the points.
+n_angles = 48
+n_radii = 8
+min_radius = 0.25
+radii = np.linspace(min_radius, 0.95, n_radii)
+
+angles = np.linspace(0, 2*math.pi, n_angles, endpoint=False)
+angles = np.repeat(angles[...,np.newaxis], n_radii, axis=1)
+angles[:,1::2] += math.pi/n_angles
+
+x = (radii*np.cos(angles)).flatten()
+y = (radii*np.sin(angles)).flatten()
+z = (np.cos(radii)*np.cos(angles*3.0)).flatten()
+
+# Create the Triangulation; no triangles so Delaunay triangulation created.
+triang = tri.Triangulation(x, y)
+
+# Mask off unwanted triangles.
+xmid = x[triang.triangles].mean(axis=1)
+ymid = y[triang.triangles].mean(axis=1)
+mask = np.where(xmid*xmid + ymid*ymid < min_radius*min_radius, 1, 0)
+triang.set_mask(mask)
+
+# pcolor plot.
+plt.figure()
+plt.gca().set_aspect('equal')
+plt.tricontourf(triang, z)
+plt.colorbar()
+plt.tricontour(triang, z, colors='k')
+plt.title('Contour plot of Delaunay triangulation')
+
+# You can specify your own triangulation rather than perform a Delaunay
+# triangulation of the points, where each triangle is given by the indices of
+# the three points that make up the triangle, ordered in either a clockwise or
+# anticlockwise manner.
+
+xy = np.asarray([
+    [-0.101,0.872],[-0.080,0.883],[-0.069,0.888],[-0.054,0.890],[-0.045,0.897],
+    [-0.057,0.895],[-0.073,0.900],[-0.087,0.898],[-0.090,0.904],[-0.069,0.907],
+    [-0.069,0.921],[-0.080,0.919],[-0.073,0.928],[-0.052,0.930],[-0.048,0.942],
+    [-0.062,0.949],[-0.054,0.958],[-0.069,0.954],[-0.087,0.952],[-0.087,0.959],
+    [-0.080,0.966],[-0.085,0.973],[-0.087,0.965],[-0.097,0.965],[-0.097,0.975],
+    [-0.092,0.984],[-0.101,0.980],[-0.108,0.980],[-0.104,0.987],[-0.102,0.993],
+    [-0.115,1.001],[-0.099,0.996],[-0.101,1.007],[-0.090,1.010],[-0.087,1.021],
+    [-0.069,1.021],[-0.052,1.022],[-0.052,1.017],[-0.069,1.010],[-0.064,1.005],
+    [-0.048,1.005],[-0.031,1.005],[-0.031,0.996],[-0.040,0.987],[-0.045,0.980],
+    [-0.052,0.975],[-0.040,0.973],[-0.026,0.968],[-0.020,0.954],[-0.006,0.947],
+    [ 0.003,0.935],[ 0.006,0.926],[ 0.005,0.921],[ 0.022,0.923],[ 0.033,0.912],
+    [ 0.029,0.905],[ 0.017,0.900],[ 0.012,0.895],[ 0.027,0.893],[ 0.019,0.886],
+    [ 0.001,0.883],[-0.012,0.884],[-0.029,0.883],[-0.038,0.879],[-0.057,0.881],
+    [-0.062,0.876],[-0.078,0.876],[-0.087,0.872],[-0.030,0.907],[-0.007,0.905],
+    [-0.057,0.916],[-0.025,0.933],[-0.077,0.990],[-0.059,0.993] ])
+x = xy[:,0]*180/3.14159
+y = xy[:,1]*180/3.14159
+x0 = -5
+y0 = 52
+z = np.exp(-0.01*( (x-x0)*(x-x0) + (y-y0)*(y-y0) ))
+
+triangles = np.asarray([
+    [67,66, 1],[65, 2,66],[ 1,66, 2],[64, 2,65],[63, 3,64],[60,59,57],
+    [ 2,64, 3],[ 3,63, 4],[ 0,67, 1],[62, 4,63],[57,59,56],[59,58,56],
+    [61,60,69],[57,69,60],[ 4,62,68],[ 6, 5, 9],[61,68,62],[69,68,61],
+    [ 9, 5,70],[ 6, 8, 7],[ 4,70, 5],[ 8, 6, 9],[56,69,57],[69,56,52],
+    [70,10, 9],[54,53,55],[56,55,53],[68,70, 4],[52,56,53],[11,10,12],
+    [69,71,68],[68,13,70],[10,70,13],[51,50,52],[13,68,71],[52,71,69],
+    [12,10,13],[71,52,50],[71,14,13],[50,49,71],[49,48,71],[14,16,15],
+    [14,71,48],[17,19,18],[17,20,19],[48,16,14],[48,47,16],[47,46,16],
+    [16,46,45],[23,22,24],[21,24,22],[17,16,45],[20,17,45],[21,25,24],
+    [27,26,28],[20,72,21],[25,21,72],[45,72,20],[25,28,26],[44,73,45],
+    [72,45,73],[28,25,29],[29,25,31],[43,73,44],[73,43,40],[72,73,39],
+    [72,31,25],[42,40,43],[31,30,29],[39,73,40],[42,41,40],[72,33,31],
+    [32,31,33],[39,38,72],[33,72,38],[33,38,34],[37,35,38],[34,38,35],
+    [35,37,36] ])
+
+# Rather than create a Triangulation object, can simply pass x, y and triangles
+# arrays to tripcolor directly.  It would be better to use a Triangulation object
+# if the same triangulation was to be used more than once to save duplicated
+# calculations.
+plt.figure()
+plt.gca().set_aspect('equal')
+plt.tricontourf(x, y, triangles, z)
+plt.colorbar()
+plt.title('Contour plot of user-specified triangulation')
+plt.xlabel('Longitude (degrees)')
+plt.ylabel('Latitude (degrees)')
+
+plt.show()

examples/pylab_examples/tricontour_vs_griddata.py

@@ -0,0 +1,47 @@
+"""
+Comparison of griddata and tricontour for an unstructured triangular grid.
+"""
+import matplotlib.pyplot as plt
+import matplotlib.tri as tri
+import numpy as np
+from numpy.random import uniform, seed
+from matplotlib.mlab import griddata
+import time
+
+seed(0)
+npts = 200
+ngridx = 100
+ngridy = 200
+x = uniform(-2,2,npts)
+y = uniform(-2,2,npts)
+z = x*np.exp(-x**2-y**2)
+
+# griddata and contour.
+start = time.clock()
+plt.subplot(211)
+xi = np.linspace(-2.1,2.1,ngridx)
+yi = np.linspace(-2.1,2.1,ngridy)
+zi = griddata(x,y,z,xi,yi,interp='linear')
+plt.contour(xi,yi,zi,15,linewidths=0.5,colors='k')
+plt.contourf(xi,yi,zi,15,cmap=plt.cm.jet)
+plt.colorbar() # draw colorbar
+plt.plot(x, y, 'ko', ms=3)
+plt.xlim(-2,2)
+plt.ylim(-2,2)
+plt.title('griddata and contour (%d points, %d grid points)' % (npts, ngridx*ngridy))
+print 'griddata and contour seconds:', time.clock() - start
+
+# tricontour.
+start = time.clock()
+plt.subplot(212)
+triang = tri.Triangulation(x, y)
+plt.tricontour(x, y, z, 15, linewidths=0.5, colors='k')
+plt.tricontourf(x, y, z, 15, cmap=plt.cm.jet)
+plt.colorbar()
+plt.plot(x, y, 'ko', ms=3)
+plt.xlim(-2,2)
+plt.ylim(-2,2)
+plt.title('tricontour (%d points)' % npts)
+print 'tricontour seconds:', time.clock() - start
+
+plt.show()

examples/pylab_examples/tripcolor_demo.py

@@ -0,0 +1,98 @@
+"""
+Pseudocolor plots of unstructured triangular grids.
+"""
+import matplotlib.pyplot as plt
+import matplotlib.tri as tri
+import numpy as np
+import math
+
+# Creating a Triangulation without specifying the triangles results in the
+# Delaunay triangulation of the points.
+
+# First create the x and y coordinates of the points.
+n_angles = 36
+n_radii = 8
+min_radius = 0.25
+radii = np.linspace(min_radius, 0.95, n_radii)
+
+angles = np.linspace(0, 2*math.pi, n_angles, endpoint=False)
+angles = np.repeat(angles[...,np.newaxis], n_radii, axis=1)
+angles[:,1::2] += math.pi/n_angles
+
+x = (radii*np.cos(angles)).flatten()
+y = (radii*np.sin(angles)).flatten()
+z = (np.cos(radii)*np.cos(angles*3.0)).flatten()
+
+# Create the Triangulation; no triangles so Delaunay triangulation created.
+triang = tri.Triangulation(x, y)
+
+# Mask off unwanted triangles.
+xmid = x[triang.triangles].mean(axis=1)
+ymid = y[triang.triangles].mean(axis=1)
+mask = np.where(xmid*xmid + ymid*ymid < min_radius*min_radius, 1, 0)
+triang.set_mask(mask)
+
+# pcolor plot.
+plt.figure()
+plt.gca().set_aspect('equal')
+plt.tripcolor(triang, z, shading='faceted')
+plt.colorbar()
+plt.title('tripcolor of Delaunay triangulation')
+
+
+# You can specify your own triangulation rather than perform a Delaunay
+# triangulation of the points, where each triangle is given by the indices of
+# the three points that make up the triangle, ordered in either a clockwise or
+# anticlockwise manner.
+
+xy = np.asarray([
+    [-0.101,0.872],[-0.080,0.883],[-0.069,0.888],[-0.054,0.890],[-0.045,0.897],
+    [-0.057,0.895],[-0.073,0.900],[-0.087,0.898],[-0.090,0.904],[-0.069,0.907],
+    [-0.069,0.921],[-0.080,0.919],[-0.073,0.928],[-0.052,0.930],[-0.048,0.942],
+    [-0.062,0.949],[-0.054,0.958],[-0.069,0.954],[-0.087,0.952],[-0.087,0.959],
+    [-0.080,0.966],[-0.085,0.973],[-0.087,0.965],[-0.097,0.965],[-0.097,0.975],
+    [-0.092,0.984],[-0.101,0.980],[-0.108,0.980],[-0.104,0.987],[-0.102,0.993],
+    [-0.115,1.001],[-0.099,0.996],[-0.101,1.007],[-0.090,1.010],[-0.087,1.021],
+    [-0.069,1.021],[-0.052,1.022],[-0.052,1.017],[-0.069,1.010],[-0.064,1.005],
+    [-0.048,1.005],[-0.031,1.005],[-0.031,0.996],[-0.040,0.987],[-0.045,0.980],
+    [-0.052,0.975],[-0.040,0.973],[-0.026,0.968],[-0.020,0.954],[-0.006,0.947],
+    [ 0.003,0.935],[ 0.006,0.926],[ 0.005,0.921],[ 0.022,0.923],[ 0.033,0.912],
+    [ 0.029,0.905],[ 0.017,0.900],[ 0.012,0.895],[ 0.027,0.893],[ 0.019,0.886],
+    [ 0.001,0.883],[-0.012,0.884],[-0.029,0.883],[-0.038,0.879],[-0.057,0.881],
+    [-0.062,0.876],[-0.078,0.876],[-0.087,0.872],[-0.030,0.907],[-0.007,0.905],
+    [-0.057,0.916],[-0.025,0.933],[-0.077,0.990],[-0.059,0.993] ])
+x = xy[:,0]*180/3.14159
+y = xy[:,1]*180/3.14159
+x0 = -5
+y0 = 52
+z = np.exp(-0.01*( (x-x0)*(x-x0) + (y-y0)*(y-y0) ))
+
+triangles = np.asarray([
+    [67,66, 1],[65, 2,66],[ 1,66, 2],[64, 2,65],[63, 3,64],[60,59,57],
+    [ 2,64, 3],[ 3,63, 4],[ 0,67, 1],[62, 4,63],[57,59,56],[59,58,56],
+    [61,60,69],[57,69,60],[ 4,62,68],[ 6, 5, 9],[61,68,62],[69,68,61],
+    [ 9, 5,70],[ 6, 8, 7],[ 4,70, 5],[ 8, 6, 9],[56,69,57],[69,56,52],
+    [70,10, 9],[54,53,55],[56,55,53],[68,70, 4],[52,56,53],[11,10,12],
+    [69,71,68],[68,13,70],[10,70,13],[51,50,52],[13,68,71],[52,71,69],
+    [12,10,13],[71,52,50],[71,14,13],[50,49,71],[49,48,71],[14,16,15],
+    [14,71,48],[17,19,18],[17,20,19],[48,16,14],[48,47,16],[47,46,16],
+    [16,46,45],[23,22,24],[21,24,22],[17,16,45],[20,17,45],[21,25,24],
+    [27,26,28],[20,72,21],[25,21,72],[45,72,20],[25,28,26],[44,73,45],
+    [72,45,73],[28,25,29],[29,25,31],[43,73,44],[73,43,40],[72,73,39],
+    [72,31,25],[42,40,43],[31,30,29],[39,73,40],[42,41,40],[72,33,31],
+    [32,31,33],[39,38,72],[33,72,38],[33,38,34],[37,35,38],[34,38,35],
+    [35,37,36] ])
+
+# Rather than create a Triangulation object, can simply pass x, y and triangles
+# arrays to tripcolor directly.  It would be better to use a Triangulation object
+# if the same triangulation was to be used more than once to save duplicated
+# calculations.
+plt.figure()
+plt.gca().set_aspect('equal')
+plt.tripcolor(x, y, triangles, z, shading='faceted')
+plt.colorbar()
+plt.title('tripcolor of user-specified triangulation')
+plt.xlabel('Longitude (degrees)')
+plt.ylabel('Latitude (degrees)')
+
+plt.show()