Damien Picard
d43702d632
This module by Maximilian Hoegner [1] was licensed under GPL v3.0 or later, and we didn't get permission to relicense it. The change of license to GPL v2.0 or later simply came during migration to SPDX headers, likely by mistake. [1] https://hoegners.de/Maxi/geo/
180 lines
6.6 KiB
Python
180 lines
6.6 KiB
Python
#!/usr/bin/env python
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# SPDX-License-Identifier: GPL-3.0-or-later
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# Copyright 2010 Maximilian Hoegner <hp.maxi@hoegners.de>.
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# geo.py is a python module with no dependencies on extra packages,
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# providing some convenience functions for working with geographic
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# coordinates
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### Part one - Functions for dealing with points on a sphere ###
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### Part two - A tolerant parser for position strings ###
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import re
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class Parser:
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""" A parser class using regular expressions. """
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def __init__(self):
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self.patterns = {}
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self.raw_patterns = {}
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self.virtual = {}
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def add(self, name, pattern, virtual=False):
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""" Adds a new named pattern (regular expression) that can reference previously added patterns by %(pattern_name)s.
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Virtual patterns can be used to make expressions more compact but don't show up in the parse tree. """
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self.raw_patterns[name] = "(?:" + pattern + ")"
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self.virtual[name] = virtual
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try:
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self.patterns[name] = ("(?:" + pattern + ")") % self.patterns
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except KeyError as e:
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raise (Exception, "Unknown pattern name: %s" % str(e))
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def parse(self, pattern_name, text):
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""" Parses 'text' with pattern 'pattern_name' and returns parse tree """
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# build pattern with subgroups
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sub_dict = {}
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subpattern_names = []
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for s in re.finditer(r"%\(.*?\)s", self.raw_patterns[pattern_name]):
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subpattern_name = s.group()[2:-2]
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if not self.virtual[subpattern_name]:
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sub_dict[subpattern_name] = "(" + self.patterns[
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subpattern_name] + ")"
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subpattern_names.append(subpattern_name)
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else:
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sub_dict[subpattern_name] = self.patterns[subpattern_name]
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pattern = "^" + (self.raw_patterns[pattern_name] % sub_dict) + "$"
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# do matching
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m = re.match(pattern, text)
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if m is None:
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return None
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# build tree recursively by parsing subgroups
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tree = {"TEXT": text}
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for i in range(len(subpattern_names)):
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text_part = m.group(i + 1)
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if text_part is not None:
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subpattern = subpattern_names[i]
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tree[subpattern] = self.parse(subpattern, text_part)
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return tree
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position_parser = Parser()
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position_parser.add("direction_ns", r"[NSns]")
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position_parser.add("direction_ew", r"[EOWeow]")
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position_parser.add("decimal_separator", r"[\.,]", True)
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position_parser.add("sign", r"[+-]")
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position_parser.add("nmea_style_degrees", r"[0-9]{2,}")
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position_parser.add("nmea_style_minutes",
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r"[0-9]{2}(?:%(decimal_separator)s[0-9]*)?")
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position_parser.add(
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"nmea_style", r"%(sign)s?\s*%(nmea_style_degrees)s%(nmea_style_minutes)s")
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position_parser.add(
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"number",
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r"[0-9]+(?:%(decimal_separator)s[0-9]*)?|%(decimal_separator)s[0-9]+")
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position_parser.add("plain_degrees", r"(?:%(sign)s\s*)?%(number)s")
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position_parser.add("degree_symbol", r"°", True)
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position_parser.add("minutes_symbol", r"'|′|`|´", True)
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position_parser.add("seconds_symbol",
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r"%(minutes_symbol)s%(minutes_symbol)s|″|\"",
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True)
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position_parser.add("degrees", r"%(number)s\s*%(degree_symbol)s")
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position_parser.add("minutes", r"%(number)s\s*%(minutes_symbol)s")
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position_parser.add("seconds", r"%(number)s\s*%(seconds_symbol)s")
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position_parser.add(
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"degree_coordinates",
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r"(?:%(sign)s\s*)?%(degrees)s(?:[+\s]*%(minutes)s)?(?:[+\s]*%(seconds)s)?|(?:%(sign)s\s*)%(minutes)s(?:[+\s]*%(seconds)s)?|(?:%(sign)s\s*)%(seconds)s"
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)
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position_parser.add(
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"coordinates_ns",
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r"%(nmea_style)s|%(plain_degrees)s|%(degree_coordinates)s")
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position_parser.add(
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"coordinates_ew",
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r"%(nmea_style)s|%(plain_degrees)s|%(degree_coordinates)s")
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position_parser.add(
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"position", (
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r"\s*%(direction_ns)s\s*%(coordinates_ns)s[,;\s]*%(direction_ew)s\s*%(coordinates_ew)s\s*|"
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r"\s*%(direction_ew)s\s*%(coordinates_ew)s[,;\s]*%(direction_ns)s\s*%(coordinates_ns)s\s*|"
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r"\s*%(coordinates_ns)s\s*%(direction_ns)s[,;\s]*%(coordinates_ew)s\s*%(direction_ew)s\s*|"
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r"\s*%(coordinates_ew)s\s*%(direction_ew)s[,;\s]*%(coordinates_ns)s\s*%(direction_ns)s\s*|"
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r"\s*%(coordinates_ns)s[,;\s]+%(coordinates_ew)s\s*"
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))
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def get_number(b):
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""" Takes appropriate branch of parse tree and returns float. """
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s = b["TEXT"].replace(",", ".")
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return float(s)
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def get_coordinate(b):
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""" Takes appropriate branch of the parse tree and returns degrees as a float. """
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r = 0.
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if b.get("nmea_style"):
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if b["nmea_style"].get("nmea_style_degrees"):
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r += get_number(b["nmea_style"]["nmea_style_degrees"])
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if b["nmea_style"].get("nmea_style_minutes"):
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r += get_number(b["nmea_style"]["nmea_style_minutes"]) / 60.
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if b["nmea_style"].get(
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"sign") and b["nmea_style"]["sign"]["TEXT"] == "-":
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r *= -1.
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elif b.get("plain_degrees"):
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r += get_number(b["plain_degrees"]["number"])
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if b["plain_degrees"].get(
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"sign") and b["plain_degrees"]["sign"]["TEXT"] == "-":
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r *= -1.
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elif b.get("degree_coordinates"):
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if b["degree_coordinates"].get("degrees"):
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r += get_number(b["degree_coordinates"]["degrees"]["number"])
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if b["degree_coordinates"].get("minutes"):
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r += get_number(b["degree_coordinates"]["minutes"]["number"]) / 60.
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if b["degree_coordinates"].get("seconds"):
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r += get_number(
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b["degree_coordinates"]["seconds"]["number"]) / 3600.
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if b["degree_coordinates"].get(
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"sign") and b["degree_coordinates"]["sign"]["TEXT"] == "-":
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r *= -1.
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return r
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def parse_position(s):
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""" Takes a (utf8-encoded) string describing a position and returns a tuple of floats for latitude and longitude in degrees.
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Tries to be as tolerant as possible with input. Returns None if parsing doesn't succeed. """
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parse_tree = position_parser.parse("position", s)
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if parse_tree is None:
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return None
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lat_sign = +1.
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if parse_tree.get(
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"direction_ns") and parse_tree["direction_ns"]["TEXT"] in ("S",
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"s"):
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lat_sign = -1.
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lon_sign = +1.
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if parse_tree.get(
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"direction_ew") and parse_tree["direction_ew"]["TEXT"] in ("W",
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"w"):
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lon_sign = -1.
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lat = lat_sign * get_coordinate(parse_tree["coordinates_ns"])
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lon = lon_sign * get_coordinate(parse_tree["coordinates_ew"])
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return lat, lon
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