Visualization Test

- Add gps data
- Add gps plotting script

src/visualization/read_gps.py

@@ -0,0 +1,60 @@
+# !/usr/bin/python
+#
+# Example code to read and plot the gps data.
+#
+# To call:
+#
+#   python read_gps.py gps.csv
+#
+
+import sys
+import matplotlib.pyplot as plt
+import numpy as np
+
+def main(args):
+
+    if len(sys.argv) < 2:
+        print('Please specify gps file')
+        return 1
+
+    gps = np.loadtxt(sys.argv[1], delimiter = ",")
+
+    num_sats = gps[:, 2]
+    lat = gps[:, 3]
+    lng = gps[:, 4]
+    alt = gps[:, 5]
+
+    lat0 = lat[0]
+    lng0 = lng[0]
+
+    dLat = lat - lat0
+    dLng = lng - lng0
+
+    r = 6400000 # approx. radius of earth (m)
+    x = r * np.cos(lat0) * np.sin(dLng)
+    y = r * np.sin(dLat)
+
+    plt.figure()
+    plt.subplot(1, 2, 1)
+    plt.scatter(x, y, 1, c=alt, linewidth=0)
+    plt.axis('equal')
+    plt.title('By altitude')
+    plt.colorbar()
+
+    plt.subplot(1, 2, 2)
+    plt.scatter(x, y, c=num_sats, linewidth=0)
+    plt.axis('equal')
+    plt.title('By number of satellites')
+    plt.colorbar()
+
+    plt.show()
+
+    fig = plt.figure()
+    ax = fig.gca(projection='3d')
+    ax.scatter(x, y, alt, 'b.')
+    plt.show()
+
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))