Changeset 2451 in lmdz_wrf for trunk/tools/geometry_tools.py

Timestamp:

Apr 21, 2019, 9:43:59 PM (6 years ago)

Author:

lfita

Message:

Adding:

• `p_spiral': Function to provide a polygon of an Archimedean spiral
• `p_triangle': Function to provide the polygon of a triangle from its 3 vertices

File:

• trunk/tools/geometry_tools.py (modified) (2 diffs)

trunk/tools/geometry_tools.py

@@ -41 +41 @@
 # p_circle: Function to get a polygon of a circle
 # p_square: Function to get a polygon square
+# p_spiral: Function to provide a polygon of an Archimedean spiral
+# p_triangle: Function to provide the polygon of a triangle from its 3 vertices
 # surface_sphere: Function to provide an sphere as matrix of x,y,z coordinates
 
@@ -436 +438 @@
 
     return circle
+
+def p_triangle(p1, p2, p3, N=4):
+    """ Function to provide the polygon of a triangle from its 3 vertices
+      p1: vertex 1 [y,x]
+      p2: vertex 2 [y,x]
+      p3: vertex 3 [y,x]
+      N: number of vertices of the triangle
+    """
+    fname = 'p_triangle'
+
+    triangle = np.zeros((N,2), dtype=np.float)
+
+    N3 = N / 3
+    # 1-2
+    dx = (p2[1]-p1[1])/N3
+    dy = (p2[0]-p1[0])/N3
+    for ip in range(N3):
+        triangle[ip,:] = [p1[0]+ip*dy,p1[1]+ip*dx]
+    # 2-3
+    dx = (p3[1]-p2[1])/N3
+    dy = (p3[0]-p2[0])/N3
+    for ip in range(N3):
+        triangle[ip+N3,:] = [p2[0]+ip*dy,p2[1]+ip*dx]
+    # 3-1
+    N32 = N - 2*N/3
+    dx = (p1[1]-p3[1])/N32
+    dy = (p1[0]-p3[0])/N32
+    for ip in range(N32):
+        triangle[ip+2*N3,:] = [p3[0]+ip*dy,p3[1]+ip*dx]
+
+    triangle[N-1,:] = p1
+
+    return triangle
+
+def p_spiral(loops, eradii, N=1000):
+    """ Function to provide a polygon of an Archimedean spiral
+        FROM: https://en.wikipedia.org/wiki/Spiral
+      loops: number of loops of the spiral
+      eradii: length of the radii of the final spiral
+      N: number of points of the polygon
+    """
+    fname = 'p_spiral'
+
+    spiral = np.zeros((N,2), dtype=np.float)
+
+    dangle = 2.*np.pi*loops/(N-1)
+    dr = eradii/(N-1)
+
+    for ia in range(N):
+        radii = dr*ia
+        spiral[ia,:] = [radii*np.sin(ia*dangle), radii*np.cos(ia*dangle)]
+
+    return spiral
 
 # Combined objects