continued work on overlaying trajectories. see #15

routes.py

@@ -1,3 +1,35 @@
+import matplotlib.pyplot as plt
+import matplotlib.patches as patches
+import matplotlib.colors as colors
+import matplotlib.cm as cm
+from PIL import Image
+import numpy as np
+from itertools import tee, izip
+import random
+
+def pairwise(iterable):
+    """
+    	returns an iterator that can traverse over an iterable by pairs
+    	https://docs.python.org/3/library/itertools.html?highlight=pairwise
+    	ex: s -> (s0,s1), (s1,s2), (s2, s3), ...
+    """
+    a, b = tee(iterable)
+    next(b, None)
+    return izip(a, b)
+
+def unique_colors(vmin, vmax):
+	"""
+		create a generator for unique matplotlib colors
+	"""
+	color_convert = cm.ScalarMappable(norm=colors.Normalize(vmin=vmin, vmax=vmax), cmap=cm.hot)
+	seen = set({})
+	while True:
+		color = color_convert.to_rgba(random.uniform(0, 1))
+		if color in seen:
+			continue
+		seen.add(color)
+		yield color
+
 def routes(vid, tracks, output):
 	"""
 		plot the routes of individual ants on top of an image of their bridge
@@ -6,4 +38,30 @@ def routes(vid, tracks, output):
 			tracks - a np array containing ant tracks
 				with cols: x_pos, y_pos, width, height, ant_id
 			output - the path to the output dir
-	"""
+	"""
+	# import image as np array and add it to an AxesImage
+	im = np.array(Image.open(vid), dtype=np.uint8)
+	fig, ax = plt.subplots(1)
+	ax.imshow(im)
+	colors = unique_colors(-100, 100)
+	# add arrows for each ant
+	for ant in np.unique(tracks[:, 4]):
+		# get tracks for this ant
+		ant_tracks = tracks[tracks[:, 4] == ant]
+		# get a unique color for this ant
+		color = next(colors)
+		# iterate over each pair of rows in the dataframe
+		for track_pair in pairwise(ant_tracks):
+			# get origin and destination points
+			origin = track_pair[0]
+			dest = track_pair[1]
+			# create arrow from origin to destination
+			# note that destination must be provided as a delta value
+			arrow = patches.Arrow(
+				origin[0], origin[1],
+				dest[0]-origin[0], dest[1]-origin[1],
+				width = 1, edgecolor = color
+			)
+			# add arrow to AxesImage
+			ax.add_patch(arrow)
+	plt.show()