def _overlay_map(self):
print "\noverlaying relief map\n"
srtm = SRTMManager(srtm_format=self.srtm_format,
patch_mode=self.patch_mode)
c = 0 # just a counter to track completion
total_samples = self.lng_sample_points * self.lat_sample_points
for y in range(1, self.lat_sample_points):
for x in range(1, self.lng_sample_points):
sample_lat = self.south_lat + y * self.lat_interval
sample_lng = self.west_lng + x * self.lng_interval
alt = srtm.get_altitude(sample_lat, sample_lng)
if alt:
if alt < self.valley["alt"]:
self.valley["alt"] = alt
self.valley["lat"] = sample_lat
self.valley["lng"] = sample_lng
if alt > self.peak["alt"]:
self.peak["alt"] = alt
self.peak["lat"] = sample_lat
self.peak["lng"] = sample_lng
self.outfile[self.lat_sample_points - y][x] = alt
c += 1.0
if (c % 1000) == 0:
percent_complete = (c / total_samples) * 100.0
update_status(percent_complete)
self._save_cache()
def overlay_gps(self, gpx, thickness=2, elevation_delta=20):
print "\noverlaying gps\n"
srtm = SRTMManager(srtm_format=self.srtm_format,
patch_mode=self.patch_mode)
prev_pixel = None
prev_alt = 0
# get a circle to draw at every point
circ = filled_circle(int(thickness))
for track in gpx.tracks:
for segment in track.segments:
for point in segment.points:
p_lat, p_lng = point.latitude, point.longitude
alt = srtm.get_altitude(p_lat, p_lng)
if not alt:
alt = prev_alt
else:
prev_alt = alt
# we need to get the percentage of the map where the
# point is and convert it to number of pixels
lat_pt = abs(p_lat - self.south_lat)
lng_pt = abs(self.east_lng - p_lng)
if lat_pt < self.lat_delta and lng_pt < self.lng_delta:
lat_pct = lat_pt / self.lat_delta
lng_pct = lng_pt / self.lng_delta
pixel_lat = int(math.floor(lat_pct *
self.lat_sample_points))
pixel_lng = int(math.floor(lng_pct *
self.lng_sample_points))
# draw a line between the pixels
if prev_pixel:
coords = bresenham_line(
(pixel_lat, pixel_lng),
(prev_pixel['lat'], prev_pixel['lng']))
for pixel in coords:
x, y = pixel
pixel_y = self.lat_sample_points - x
pixel_x = self.lng_sample_points - y
for point in circ:
x, y = point
circ_x = pixel_x + x
circ_y = pixel_y + y
if circ_x >= self.lng_sample_points:
circ_x = self.lng_sample_points - 1
if circ_y >= self.lat_sample_points:
circ_y = self.lat_sample_points - 1
self.outfile[circ_y, circ_x] = alt + \
int(elevation_delta)
prev_pixel = {'lat': pixel_lat, 'lng': pixel_lng}
