pyhamtools/pyhamtools/locator.py
2015-12-30 19:55:51 +01:00

359 lines
11 KiB
Python

from __future__ import division
from math import pi, sin, cos, atan2, sqrt, radians, log, tan, degrees
from datetime import datetime
import pytz
import ephem
UTC = pytz.UTC
def latlong_to_locator (latitude, longitude):
"""converts WGS84 coordinates into the corresponding Maidenhead Locator
Args:
latitude (float): Latitude
longitude (float): Longitude
Returns:
string: Maidenhead locator
Raises:
ValueError: When called with wrong or invalid input args
TypeError: When args are non float values
Example:
The following example converts latitude and longitude into the Maidenhead locator
>>> from pyhamtools.locator import latlong_to_locator
>>> latitude = 48.5208333
>>> longitude = 9.375
>>> latlong_to_locator(latitude, longitude)
'JN48QM'
Note:
Latitude (negative = West, positive = East)
Longitude (negative = South, positive = North)
"""
if longitude >= 180 or longitude <= -180:
raise ValueError
if latitude >= 90 or latitude <= -90:
raise ValueError
longitude += 180;
latitude +=90;
locator = chr(ord('A') + int(longitude / 20))
locator += chr(ord('A') + int(latitude / 10))
locator += chr(ord('0') + int((longitude % 20) / 2))
locator += chr(ord('0') + int(latitude % 10))
locator += chr(ord('A') + int((longitude - int(longitude / 2) * 2) / (2 / 24)))
locator += chr(ord('A') + int((latitude - int(latitude / 1) * 1 ) / (1 / 24)))
return locator
def locator_to_latlong (locator):
"""converts Maidenhead locator in the corresponding WGS84 coordinates
Args:
locator (string): Locator, either 4 or 6 characters
Returns:
tuple (float, float): Latitude, Longitude
Raises:
ValueError: When called with wrong or invalid input arg
TypeError: When arg is not a string
Example:
The following example converts a Maidenhead locator into Latitude and Longitude
>>> from pyhamtools.locator import locator_to_latlong
>>> latitude, longitude = locator_to_latlong("JN48QM")
>>> print latitude, longitude
48.5208333333 9.375
Note:
Latitude (negative = West, positive = East)
Longitude (negative = South, positive = North)
"""
locator = locator.upper()
if len(locator) == 5 or len(locator) < 4:
raise ValueError
if ord(locator[0]) > ord('R') or ord(locator[0]) < ord('A'):
raise ValueError
if ord(locator[1]) > ord('R') or ord(locator[1]) < ord('A'):
raise ValueError
if ord(locator[2]) > ord('9') or ord(locator[2]) < ord('0'):
raise ValueError
if ord(locator[3]) > ord('9') or ord(locator[3]) < ord('0'):
raise ValueError
if len(locator) == 6:
if ord(locator[4]) > ord('X') or ord(locator[4]) < ord('A'):
raise ValueError
if ord (locator[5]) > ord('X') or ord(locator[5]) < ord('A'):
raise ValueError
longitude = (ord(locator[0]) - ord('A')) * 20 - 180
latitude = (ord(locator[1]) - ord('A')) * 10 - 90
longitude += (ord(locator[2]) - ord('0')) * 2
latitude += (ord(locator[3]) - ord('0'))
if len(locator) == 6:
longitude += ((ord(locator[4])) - ord('A')) * (2 / 24)
latitude += ((ord(locator[5])) - ord('A')) * (1 / 24)
# move to center of subsquare
longitude += 1 / 24
latitude += 0.5 / 24
else:
# move to center of square
longitude += 1;
latitude += 0.5;
return latitude, longitude
def calculate_distance(locator1, locator2):
"""calculates the (shortpath) distance between two Maidenhead locators
Args:
locator1 (string): Locator, either 4 or 6 characters
locator2 (string): Locator, either 4 or 6 characters
Returns:
float: Distance in km
Raises:
ValueError: When called with wrong or invalid input arg
AttributeError: When args are not a string
Example:
The following calculates the distance between two Maidenhead locators in km
>>> from pyhamtools.locator import calculate_distance
>>> calculate_distance("JN48QM", "QF67bf")
16466.413
"""
R = 6371 #earh radius
lat1, long1 = locator_to_latlong(locator1)
lat2, long2 = locator_to_latlong(locator2)
d_lat = radians(lat2) - radians(lat1)
d_long = radians(long2) - radians(long1)
r_lat1 = radians(lat1)
r_long1 = radians(long1)
r_lat2 = radians(lat2)
r_long2 = radians(long2)
a = sin(d_lat/2) * sin(d_lat/2) + cos(r_lat1) * cos(r_lat2) * sin(d_long/2) * sin(d_long/2)
c = 2 * atan2(sqrt(a), sqrt(1-a))
d = R * c #distance in km
return d;
def calculate_distance_longpath(locator1, locator2):
"""calculates the (longpath) distance between two Maidenhead locators
Args:
locator1 (string): Locator, either 4 or 6 characters
locator2 (string): Locator, either 4 or 6 characters
Returns:
float: Distance in km
Raises:
ValueError: When called with wrong or invalid input arg
AttributeError: When args are not a string
Example:
The following calculates the longpath distance between two Maidenhead locators in km
>>> from pyhamtools.locator import calculate_distance_longpath
>>> calculate_distance_longpath("JN48QM", "QF67bf")
23541.5867
"""
c = 40008 #[km] earth circumference
sp = calculate_distance(locator1, locator2)
return c - sp
def calculate_heading(locator1, locator2):
"""calculates the heading from the first to the second locator
Args:
locator1 (string): Locator, either 4 or 6 characters
locator2 (string): Locator, either 4 or 6 characters
Returns:
float: Heading in deg
Raises:
ValueError: When called with wrong or invalid input arg
AttributeError: When args are not a string
Example:
The following calculates the heading from locator1 to locator2
>>> from pyhamtools.locator import calculate_heading
>>> calculate_heading("JN48QM", "QF67bf")
74.3136
"""
lat1, long1 = locator_to_latlong(locator1)
lat2, long2 = locator_to_latlong(locator2)
r_lat1 = radians(lat1)
r_lon1 = radians(long1)
r_lat2 = radians(lat2)
r_lon2 = radians(long2)
d_lon = radians(long2 - long1)
b = atan2(sin(d_lon)*cos(r_lat2),cos(r_lat1)*sin(r_lat2)-sin(r_lat1)*cos(r_lat2)*cos(d_lon)) # bearing calc
bd = degrees(b)
br,bn = divmod(bd+360,360) # the bearing remainder and final bearing
return bn
def calculate_heading_longpath(locator1, locator2):
"""calculates the heading from the first to the second locator (long path)
Args:
locator1 (string): Locator, either 4 or 6 characters
locator2 (string): Locator, either 4 or 6 characters
Returns:
float: Long path heading in deg
Raises:
ValueError: When called with wrong or invalid input arg
AttributeError: When args are not a string
Example:
The following calculates the long path heading from locator1 to locator2
>>> from pyhamtools.locator import calculate_heading_longpath
>>> calculate_heading_longpath("JN48QM", "QF67bf")
254.3136
"""
heading = calculate_heading(locator1, locator2)
lp = (heading + 180)%360
return lp
def calculate_sunrise_sunset(locator, calc_date=datetime.utcnow()):
"""calculates the next sunset and sunrise for a Maidenhead locator at a give date & time
Args:
locator1 (string): Maidenhead Locator, either 4 or 6 characters
calc_date (datetime, optional): Starting datetime for the calculations (UTC)
Returns:
dict: Containing datetimes for morning_dawn, sunrise, evening_dawn, sunset
Raises:
ValueError: When called with wrong or invalid input arg
AttributeError: When args are not a string
Example:
The following calculates the next sunrise & sunset for JN48QM on the 1./Jan/2014
>>> from pyhamtools.locator import calculate_sunrise_sunset
>>> from datetime import datetime
>>> import pytz
>>> UTC = pytz.UTC
>>> myDate = datetime(year=2014, month=1, day=1, tzinfo=UTC)
>>> calculate_sunrise_sunset("JN48QM", myDate)
{
'morning_dawn': datetime.datetime(2014, 1, 1, 6, 36, 51, 710524, tzinfo=<UTC>),
'sunset': datetime.datetime(2014, 1, 1, 16, 15, 23, 31016, tzinfo=<UTC>),
'evening_dawn': datetime.datetime(2014, 1, 1, 15, 38, 8, 355315, tzinfo=<UTC>),
'sunrise': datetime.datetime(2014, 1, 1, 7, 14, 6, 162063, tzinfo=<UTC>)
}
"""
morning_dawn = None
sunrise = None
evening_dawn = None
sunset = None
latitude, longitude = locator_to_latlong(locator)
if type(calc_date) != datetime:
raise ValueError
sun = ephem.Sun()
home = ephem.Observer()
home.lat = str(latitude)
home.long = str(longitude)
home.date = calc_date
sun.compute(home)
try:
nextrise = home.next_rising(sun)
nextset = home.next_setting(sun)
home.horizon = '-6'
beg_twilight = home.next_rising(sun, use_center=True)
end_twilight = home.next_setting(sun, use_center=True)
morning_dawn = beg_twilight.datetime()
sunrise = nextrise.datetime()
evening_dawn = nextset.datetime()
sunset = end_twilight.datetime()
#if sun never sets or rises (e.g. at polar circles)
except ephem.AlwaysUpError as e:
morning_dawn = None
sunrise = None
evening_dawn = None
sunset = None
except ephem.NeverUpError as e:
morning_dawn = None
sunrise = None
evening_dawn = None
sunset = None
result = {}
result['morning_dawn'] = morning_dawn
result['sunrise'] = sunrise
result['evening_dawn'] = evening_dawn
result['sunset'] = sunset
if morning_dawn:
result['morning_dawn'] = morning_dawn.replace(tzinfo=UTC)
if sunrise:
result['sunrise'] = sunrise.replace(tzinfo=UTC)
if evening_dawn:
result['evening_dawn'] = evening_dawn.replace(tzinfo=UTC)
if sunset:
result['sunset'] = sunset.replace(tzinfo=UTC)
return result