102 lines
3.3 KiB
Python
102 lines
3.3 KiB
Python
# -*- coding: utf-8 -*-
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'''
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geodata.coordinates.conversion
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------------------------------
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Geographic coordinates typically come in two flavors: decimal and
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DMS (degree-minute-second). This module parses a coordinate string
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in just about any format. This was originally created for parsing
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lat/lons found on the web.
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Usage:
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>>> latlon_to_decimal('40°42′46″N', '74°00′21″W') # returns (40.71277777777778, 74.00583333333333)
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>>> latlon_to_decimal('40,74 N', '74,001 W') # returns (40.74, -74.001)
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'''
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import re
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from geodata.encoding import safe_decode
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beginning_re = re.compile('^[^0-9\-]+', re.UNICODE)
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end_re = re.compile('[^0-9]+$', re.UNICODE)
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latitude_dms_regex = re.compile(ur'^(-?[0-9]{1,2})[ ]*[ :°ºd][ ]*([0-5]?[0-9])?[ ]*[:\'\u2032m]?[ ]*([0-5]?[0-9](?:\.\d+)?)?[ ]*[:\?\"\u2033s]?[ ]*(N|n|S|s)?$', re.I | re.UNICODE)
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longitude_dms_regex = re.compile(ur'^(-?1[0-8][0-9]|0?[0-9]{1,2})[ ]*[ :°ºd][ ]*([0-5]?[0-9])?[ ]*[:\'\u2032m]?[ ]*([0-5]?[0-9](?:\.\d+)?)?[ ]*[:\?\"\u2033s]?[ ]*(E|e|W|w)?$', re.I | re.UNICODE)
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latitude_decimal_with_direction_regex = re.compile('^(-?[0-9][0-9](?:\.[0-9]+))[ ]*[ :°ºd]?[ ]*(N|n|S|s)$', re.I)
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longitude_decimal_with_direction_regex = re.compile('^(-?1[0-8][0-9]|0?[0-9][0-9](?:\.[0-9]+))[ ]*[ :°ºd]?[ ]*(E|e|W|w)$', re.I)
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direction_sign_map = {'n': 1, 's': -1, 'e': 1, 'w': -1}
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def direction_sign(d):
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if d is None:
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return 1
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d = d.lower().strip()
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if d in direction_sign_map:
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return direction_sign_map[d]
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else:
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raise ValueError('Invalid direction: {}'.format(d))
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def int_or_float(d):
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try:
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return int(d)
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except ValueError:
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return float(d)
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def degrees_to_decimal(degrees, minutes, seconds):
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degrees = int_or_float(degrees)
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minutes = int_or_float(minutes)
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seconds = int_or_float(seconds)
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return degrees + (minutes / 60.0) + (seconds / 3600.0)
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def latlon_to_decimal(latitude, longitude):
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have_lat = False
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have_lon = False
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latitude = safe_decode(latitude).strip(u' ,;|')
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longitude = safe_decode(longitude).strip(u' ,;|')
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latitude = latitude.replace(u',', u'.')
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longitude = longitude.replace(u',', u'.')
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lat_dms = latitude_dms_regex.match(latitude)
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lat_dir = latitude_decimal_with_direction_regex.match(latitude)
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if lat_dms:
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d, m, s, c = lat_dms.groups()
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sign = direction_sign(c)
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latitude = degrees_to_decimal(d or 0, m or 0, s or 0)
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have_lat = True
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elif lat_dir:
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d, c = lat_dir.groups()
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sign = direction_sign(c)
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latitude = float(d) * sign
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have_lat = True
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else:
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latitude = re.sub(beginning_re, u'', latitude)
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latitude = re.sub(end_re, u'', latitude)
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lon_dms = longitude_dms_regex.match(longitude)
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lon_dir = longitude_decimal_with_direction_regex.match(longitude)
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if lon_dms:
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d, m, s, c = lon_dms.groups()
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sign = direction_sign(c)
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longitude = degrees_to_decimal(d or 0, m or 0, s or 0)
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have_lon = True
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elif lon_dir:
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d, c = lon_dir.groups()
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sign = direction_sign(c)
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longitude = float(d) * sign
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have_lon = True
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else:
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longitude = re.sub(beginning_re, u'', longitude)
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longitude = re.sub(end_re, u'', longitude)
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return float(latitude), float(longitude)
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