Add elevation chart

tikz/gpx-gps-elevation-chart-generator/elevation_chart_gen.py

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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""Generate an elevation chart from a GPX file."""
+
+import gpxpy
+import logging
+import sys
+from math import sin, cos, sqrt, atan2, radians
+
+logging.basicConfig(format='%(asctime)s %(levelname)s %(message)s',
+                    level=logging.DEBUG,
+                    stream=sys.stdout)
+
+
+def main(gpx_file):
+    """Orchestrate."""
+    gpx_points = parse_gpx_points(gpx_file)
+    logging.info("Loaded %i points from file '%s'.", len(gpx_points), gpx_file)
+    chart_points = get_chart_points(gpx_points)
+    with open("data.csv", "w") as f:
+        f.write("dist,ele\n")
+        for p in chart_points:
+            f.write("%0.4f,%0.4f\n" % (p['dist']/1000.0, p['ele']))
+
+
+def get_dist(lat1, lon1, lat2, lon2):
+    """Get the distance in km of two points on earth."""
+    R = 6373.0
+
+    lat1 = radians(52.2296756)
+    lon1 = radians(21.0122287)
+    lat2 = radians(52.406374)
+    lon2 = radians(16.9251681)
+
+    dlon = lon2 - lon1
+    dlat = lat2 - lat1
+
+    a = sin(dlat / 2)**2 + cos(lat1) * cos(lat2) * sin(dlon / 2)**2
+    c = 2 * atan2(sqrt(a), sqrt(1 - a))
+
+    distance = R * c
+    return distance
+
+
+def parse_gpx_points(gpx_file):
+    """Get all points as a list from gpx_file."""
+    with open(gpx_file) as f:
+        gpx_data_txt = f.read()
+    gpx = gpxpy.parse(gpx_data_txt)
+    points = []
+    for track in gpx.tracks:
+        for segment in track.segments:
+            for point in segment.points:
+                points.append({'lat': point.latitude,
+                               'lon': point.longitude,
+                               'ele': point.elevation})
+    return points
+
+
+def get_chart_points(points):
+    """Get a list of points (x, y) with x=traveled distance, y=eleveation."""
+    chart_points = [{'dist': 0, 'ele': points[0]['ele']}]
+    dist = 0.0
+    get_dist = gpxpy.geo.haversine_distance
+    for i in range(1, len(points)):
+        dist += get_dist(points[i - 1]['lat'], points[i - 1]['lon'],
+                         points[i]['lat'], points[i]['lon'])
+        chart_points.append({'dist': dist, 'ele': points[i]['ele']})
+    return chart_points
+
+
+def get_parser():
+    """Get parser object for elevation_chart_gen.py."""
+    from argparse import ArgumentParser, ArgumentDefaultsHelpFormatter
+    parser = ArgumentParser(description=__doc__,
+                            formatter_class=ArgumentDefaultsHelpFormatter)
+    parser.add_argument("-f", "--file",
+                        dest="filename",
+                        help="GPX file",
+                        metavar="FILE",
+                        required=True)
+    return parser
+
+
+if __name__ == "__main__":
+    args = get_parser().parse_args()
+    main(args.filename)