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Diffstat (limited to 'osm_parser.py')
| -rw-r--r-- | osm_parser.py | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/osm_parser.py b/osm_parser.py new file mode 100644 index 0000000..60754c9 --- /dev/null +++ b/osm_parser.py @@ -0,0 +1,201 @@ +# Henrik 'catears' Adolfsson, henad221@student.liu.se +# Date: 2014-11-09 +# Copyright (c) 2014 Henrik Adolfsson +# Licensed under MIT License (see bottom of file) + +""" +In this file you will find a class that can parse OpenStreetMap Node-data and OpenStreetMap Way-data. +There is a helper function for retrieving a default parser called get_default_parser(fname) +It provides you with a basic parser that can iterate over nodes and iterate over ways + +If you want to tweak the behaviour of the default parser you can change the +tags that will be returned with the tuples DEFAULT_NODE/WAY_TAGS under the Module Config-section + +The default parser will return edges with tags if they exist in "DEFAULT_WAY_TAGS". +You can tweak the behaviour of the default parser so that it will return all tags it encounters. +You do this by calling 'get_default_parser(fname, allow_all=True)' + +The only dependency of the module is the xml.etree.ElementTree which +is a part of the python library for both py2 and py3 +""" + +import xml.etree.ElementTree as ET +FILEEXT = ".osm" + + +########################################## +# Module config # +########################################## +DEFAULT_NODE_TAGS = ('id', 'lat', 'lon') +DEFAULT_WAY_TAGS = ('highway', 'name', 'oneway') + + +########################################## +# OSM Specific Keys # +########################################## +OSM_NODE = "node" +OSM_WAY = "way" +OSM_WAYNODE = "nd" +OSM_NODE_REFERENCE = "ref" +OSM_TAG = "tag" +OSM_WAY_ID = "id" +OSM_TAG_KEY = "k" +OSM_TAG_VALUE = "v" + + +########################################## +# Ouput keys for returned dictionary # +########################################## +OUT_EDGE_ID = "id" +OUT_EDGES_KEY = "road" +OUT_TAGS_KEY = "tags" + + +########################################## +# Parser implementation # +########################################## + +class OSMParser: + """ + A Parser that parses OSM data and enables iterating over + Nodes and Ways as well as selecting which tags to show from the data. + + One of the focuses of the parser has been to create something simple + that abstracts away as much object oriented features as possible from a normal user + + Essentially the parser will parse the XML file and convert each element present + in the XML file into a python dictionary. (since this key-value stuff is basically what xml is) + """ + + + def __init__(self, fname, all_way_tags): + """ + Initialize. if all_way_tags is True then the parser will return ways + with all tags, otherwise it will only choose specific tags + """ + if not FILEEXT in fname: + fname = fname + FILEEXT + + self.tree = ET.parse(fname) # ET, parse home + self.node_tags = set() + self.way_tags = set() + self.allow_all = all_way_tags + + + def add_node_tag(self, tag): + """ Adds a tag to be searched for when looking at nodes """ + self.node_tags.add(tag) + + + def add_way_tag(self, tag): + """ Adds a tag to be searched for when looking at ways (edges) """ + self.way_tags.add(tag) + + + def iter_nodes(self): + """ + Iterator-object for all nodes in osm-tree. + Returns a dictionary with the (manually) added tags + """ + # Root of xml tree + root = self.tree.getroot() + for node in root.iter(OSM_NODE): + + # yield a dictionary with all tags that are added to self.node_tags + yield { tag : node.attrib.get(tag, None) + for tag in self.node_tags + if tag in node.attrib } + + + def iter_ways(self): + """ + Iterator-object for all ways (edges) in osm-tree. + Returns a dictionary with the ways + """ + # Root of xml-tree + root = self.tree.getroot() + for way in root.iter(OSM_WAY): + + # Take out roads and tags + road = tuple( node.attrib[OSM_NODE_REFERENCE] + for node in way.iter(OSM_WAYNODE) ) + tags = { tag.attrib[OSM_TAG_KEY] : tag.attrib[OSM_TAG_VALUE] + for tag in way.iter(OSM_TAG) + if self.allow_all or tag.attrib[OSM_TAG_KEY] in self.way_tags} + + # Yield the edge id, the road and the tags + yield { + OUT_EDGE_ID : way.attrib[OSM_WAY_ID], + OUT_EDGES_KEY : road, + OUT_TAGS_KEY : tags, + } + + +########################################## +# Example Usage and Default Getter # +########################################## + +def get_default_parser(fname, allow_all=False, verbose=True): + """ + Returns a default parser + The config used can be tweaked inside the Module Config section + + allow_all sets if the parser should take all tags or if it should just + take the tags specified, in this case all tags inside DEFAULT_WAY_TAGS + """ + if verbose: + print("Parsing OSM data from: {}".format(fname)) + + parser = OSMParser(fname, allow_all) + + # Add default node and way tags + for tag in DEFAULT_NODE_TAGS: + parser.add_node_tag(tag) + + for tag in DEFAULT_WAY_TAGS: + parser.add_way_tag(tag) + + return parser + + +def print_osm_data(fname): + """ + Prints all the nodes and all the ways in the map + Good example of how to use the code =D + """ + # Create parser + parser = get_default_parser(fname) + + # Print all nodes + for node in parser.iter_nodes(): + print (node) + + # Print all ways that are tagged with highway + for way in parser.iter_ways(): + if 'highway' in way['tags']: + print (way) + + +""" +The MIT License + +Copyright (c) 2014 Henrik Adolfsson + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. +""" |