SVMyRide

#!/usr/bin/python
"""
SVMyRide

Takes a gpx file, loads the points + calcs bearing, gets a matching SV image
Only produces images: convert to a video via ffmpeg, avidemux, etc
"""

import xml.etree.ElementTree as ET
import urllib, os, math

BOFFSET = 2 # averages out bearing over +- 2 points to stop video shaking
            # from side-to side. Should probably only look forward instead...

def calc_bearing(pointA, pointB):
    lat1 = math.radians(pointA[0])
    lat2 = math.radians(pointB[0])
    diffLong = math.radians(pointB[1] - pointA[1])

    x = math.sin(diffLong) * math.cos(lat2)
    y = math.cos(lat1) * math.sin(lat2) - (math.sin(lat1) * math.cos(lat2) * math.cos(diffLong))

    initial_bearing = math.atan2(x, y)
    initial_bearing = math.degrees(initial_bearing)
    compass_bearing = (initial_bearing + 360) % 360

    return compass_bearing

#filename is hard-coded (sorry!)
#also gpx data from non-Strava sources may need extra processing here
gpx_file = ET.parse('test.gpx')
gpx_trackseg = gpx_file.getroot()[1][1]
points = []
for point in gpx_trackseg:
    points.append(point)

#smooth/average out bearings: this should really be changed to only look forward
smoothBearing = []
for iPoint in range(len(points)):
    if BOFFSET <= iPoint < len(points)-BOFFSET:
        smoothBearing.append(int(calc_bearing((float(points[iPoint-BOFFSET].attrib['lat']),float(points[iPoint-BOFFSET].attrib['lon'])),(float(points[iPoint+BOFFSET].attrib['lat']),float(points[iPoint+BOFFSET].attrib['lon'])))))
points = points[BOFFSET:-BOFFSET]

iPoint = 1
while iPoint < len(points):
    # NB: YOU NEED TO ADD YOU OWN GOOGLE API KEY TO THE LINE BELOW:
    sUrl = 'http://maps.googleapis.com/maps/api/streetview?size=640x400&location=%f,%f&heading=%d&pitch=0&sensor=false&key=PUTYOURKEYHERE' % (float(points[iPoint].attrib['lat']),float(points[iPoint].attrib['lon']),smoothBearing[iPoint])
    urllib.urlretrieve(sUrl, '%05d.png' % iPoint)
    iPoint += 1