def check_distances():
"""
check distance between lat-lon points with the different aggregation zones
"""
a_in = h5py.File('/homespace/gaubert/viirs/Mband-SDR/GMODO_npp_d20030125_t0847056_e0848301_b00015_c20090513182937526121_gisf_pop.h5')
lats = load_array(a_in['All_Data']['VIIRS-MOD-GEO_All']['Latitude'])
lons = load_array(a_in['All_Data']['VIIRS-MOD-GEO_All']['Longitude'])
index = 0
f_d = open("/tmp/distance_results", "w")
f_csv = open("/tmp/distance_results.csv", "w")
#write header
for j in xrange(1, len(lats[0])):
f_csv.write('pix(%d)-pix(%d), ' % (j, j-1))
f_csv.write('\n')
print("%s scan lines to write " % (len(lats)))
for lat_scan in lats:
lon_scan = lons[index]
print("======================== Scan line %d ========================\n" % index)
f_d.write("======================== Scan line %d ========================\n" % index)
for i in xrange(0,len(lat_scan)):
if i == 0:
continue
point1 = (lat_scan[i-1], lon_scan[i-1])
point2 = (lat_scan[i], lon_scan[i])
distance = geo_utils.distance(point1[0], point1[1], point2[0], point2[1])
str_to_write = 'distance(pix(%d)-pix(%d) = %f km' % (i-1, i, distance)
#print(str_to_write)
#f_d.write('%s\n' % str_to_write)
f_csv.write('%f,' % (distance))
index += 1
f_csv.write('\n')
def distance_array(lat1_arr, lon1_arr, lat2_arr, lon2_arr):
""" calculate the distance between each points """
if lat1_arr.size != lat2_arr.size:
raise Exception("Latitude arrays have different sizes")
if lon1_arr.size != lon2_arr.size:
raise Exception("Longitude arrays have different sizes")
results = numpy.empty(lat1_arr.size)
print("Compute distances for %d points\n" % (lat1_arr.size))
for x in xrange(0, lat1_arr.size):
results[x] = geo.distance(lat1_arr[x], lon1_arr[x], lat2_arr[x], lon2_arr[x])
#print("Calculate distance (%f) between p1:(%f,%f) and p2:(%f,%f)\n" %(results[x], lat1_arr[x], lon1_arr[x], lat2_arr[x], lon2_arr[x]))
return results
