SF.net SVN: matplotlib: [5326] trunk/htdocs/screenshots/ellipse_large.py

[<jd...@us...>]

Revision: 5326
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=5326&view=rev
Author:   jdh2358
Date:     2008-05-30 10:30:59 -0700 (Fri, 30 May 2008)

Log Message:
-----------
added ellipse demo

Added Paths:
-----------
    trunk/htdocs/screenshots/ellipse_large.py

Added: trunk/htdocs/screenshots/ellipse_large.py
===================================================================
--- trunk/htdocs/screenshots/ellipse_large.py	                        (rev 0)
+++ trunk/htdocs/screenshots/ellipse_large.py	2008-05-30 17:30:59 UTC (rev 5326)
@@ -0,0 +1,149 @@
+
+# This example can be boiled down to a more simplistic example
+# to show the problem, but bu including the upper and lower
+# bound ellipses, it demonstrates how significant this error
+# is to our plots.
+
+import math
+from pylab import *
+from matplotlib.patches import Ellipse, Arc
+
+# given a point x, y
+x = 2692.440
+y = 6720.850
+
+# get is the radius of a circle through this point
+r = math.sqrt( x*x+y*y )
+
+# show some comparative circles
+delta = 6
+
+
+##################################################
+def custom_ellipse( ax, x, y, major, minor, theta, numpoints = 750, **kwargs ):
+   xs = []
+   ys = []
+   incr = 2.0*math.pi / numpoints
+   incrTheta = 0.0
+   while incrTheta <= (2.0*math.pi):
+      a = major * math.cos( incrTheta )
+      b = minor * math.sin( incrTheta )
+      l = math.sqrt( ( a**2 ) + ( b**2 ) )
+      phi = math.atan2( b, a )
+      incrTheta += incr
+
+      xs.append( x + ( l * math.cos( theta + phi ) ) )
+      ys.append( y + ( l * math.sin( theta + phi ) ) )
+   # end while
+
+   incrTheta = 2.0*math.pi
+   a = major * math.cos( incrTheta )
+   b = minor * math.sin( incrTheta )
+   l = sqrt( ( a**2 ) + ( b**2 ) )
+   phi = math.atan2( b, a )
+   xs.append( x + ( l * math.cos( theta + phi ) ) )
+   ys.append( y + ( l * math.sin( theta + phi ) ) )
+
+   ellipseLine = ax.plot( xs, ys, **kwargs )
+
+
+
+
+##################################################
+# make the axes
+ax1 = subplot( 311, aspect='equal' )
+ax1.set_aspect( 'equal', 'datalim' )
+
+# make the lower-bound ellipse
+diam = (r - delta) * 2.0
+lower_ellipse = Ellipse( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkgreen" )
+ax1.add_patch( lower_ellipse )
+
+# make the target ellipse
+diam = r * 2.0
+target_ellipse = Ellipse( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkred" )
+ax1.add_patch( target_ellipse )
+
+# make the upper-bound ellipse
+diam = (r + delta) * 2.0
+upper_ellipse = Ellipse( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkblue" )
+ax1.add_patch( upper_ellipse )
+
+# make the target
+diam = delta * 2.0
+target = Ellipse( (x, y), diam, diam, 0.0, fill=False, edgecolor="#DD1208" )
+ax1.add_patch( target )
+
+# give it a big marker
+ax1.plot( [x], [y], marker='x', linestyle='None', mfc='red', mec='red', markersize=10 )
+
+##################################################
+# make the axes
+ax = subplot( 312, aspect='equal' , sharex=ax1, sharey=ax1)
+ax.set_aspect( 'equal', 'datalim' )
+
+# make the lower-bound arc
+diam = (r - delta) * 2.0
+lower_arc = Arc( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkgreen" )
+ax.add_patch( lower_arc )
+
+# make the target arc
+diam = r * 2.0
+target_arc = Arc( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkred" )
+ax.add_patch( target_arc )
+
+# make the upper-bound arc
+diam = (r + delta) * 2.0
+upper_arc = Arc( (0.0, 0.0), diam, diam, 0.0, fill=False, edgecolor="darkblue" )
+ax.add_patch( upper_arc )
+
+# make the target
+diam = delta * 2.0
+target = Arc( (x, y), diam, diam, 0.0, fill=False, edgecolor="#DD1208" )
+ax.add_patch( target )
+
+# give it a big marker
+ax.plot( [x], [y], marker='x', linestyle='None', mfc='red', mec='red', markersize=10 )
+
+
+
+
+
+##################################################
+# now lets do the same thing again using a custom ellipse function
+
+
+
+# make the axes
+ax = subplot( 313, aspect='equal', sharex=ax1, sharey=ax1 )
+ax.set_aspect( 'equal', 'datalim' )
+
+# make the lower-bound ellipse
+custom_ellipse( ax, 0.0, 0.0, r-delta, r-delta, 0.0, color="darkgreen" )
+
+# make the target ellipse
+custom_ellipse( ax, 0.0, 0.0, r, r, 0.0, color="darkred" )
+
+# make the upper-bound ellipse
+custom_ellipse( ax, 0.0, 0.0, r+delta, r+delta, 0.0, color="darkblue" )
+
+# make the target
+custom_ellipse( ax, x, y, delta, delta, 0.0, color="#BB1208" )
+
+# give it a big marker
+ax.plot( [x], [y], marker='x', linestyle='None', mfc='red', mec='red', markersize=10 )
+
+
+# give it a big marker
+ax.plot( [x], [y], marker='x', linestyle='None', mfc='red', mec='red', markersize=10 )
+
+##################################################
+# lets zoom in to see the area of interest
+
+ax1.set_xlim(2650, 2735)
+ax1.set_ylim(6705, 6735)
+
+savefig("ellipse")
+show()
+
+


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