Merge pull request #2 from geopython/georss

GeoRSS

Author: constantinius

README.md

@@ -14,7 +14,7 @@ $ pip install pygml
 
 ## Features
 
-Parse GML 3.1, 3.2 and compact encoded GML 3.3 geometries to a [`__geo_interface__`](https://gist.github.com/sgillies/2217756) compliant class.
+Parse GML 3.1, 3.2, compact encoded GML 3.3 and GeoRSS geometries to a [`__geo_interface__`](https://gist.github.com/sgillies/2217756) compliant class.
 
 
 ```python
@@ -25,7 +25,7 @@ Parse GML 3.1, 3.2 and compact encoded GML 3.3 geometries to a [`__geo_interface
 ... </gml:Point>
 ... """)
 >>> print(geom)
-Geometry(geometry={'type': 'Point', 'coordinates': [1.0, 1.0]})
+Geometry(geometry={'type': 'Point', 'coordinates': (1.0, 1.0)})
 >>> print(geom.__geo_interface__)
-{'type': 'Point', 'coordinates': [1.0, 1.0]}
+{'type': 'Point', 'coordinates': (1.0, 1.0)}
 ```

pygml/basics.py

@@ -84,6 +84,12 @@ def parse_pos(value: str) -> Coordinate:
     return tuple(float(v) for v in value.split())
 
 
+def swap_coordinate_xy(coordinate: Coordinate) -> Coordinate:
+    """ Swaps the X and Y coordinates of a given coordinate
+    """
+    return (coordinate[1], coordinate[0], *coordinate[2:])
+
+
 def swap_coordinates_xy(coordinates: Coordinates) -> Coordinates:
     """ Swaps the X and Y coordinates of a given coordinates list
     """

pygml/georss.py

@@ -0,0 +1,122 @@
+# ------------------------------------------------------------------------------
+#
+# Project: pygml <https://github.com/geopython/pygml>
+# Authors: Fabian Schindler <[email protected]>
+#
+# ------------------------------------------------------------------------------
+# Copyright (C) 2021 EOX IT Services GmbH
+#
+# 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 of this Software or works derived from this 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.
+# ------------------------------------------------------------------------------
+
+from typing import List
+
+from lxml import etree
+
+from .basics import (
+    parse_pos, parse_poslist, swap_coordinate_xy, swap_coordinates_xy
+)
+from .types import GeomDict
+from .pre_v32 import NAMESPACE as NAMESPACE_PRE32, parse_pre_v32
+from .v32 import NAMESPACE as NAMESPACE_32, parse_v32
+from .v33 import NAMESPACE as NAMESPACE_33_CE, parse_v33_ce
+
+
+NAMESPACE = 'http://www.georss.org/georss'
+NSMAP = {'georss': NAMESPACE}
+
+
+Element = etree._Element
+Elements = List[Element]
+
+
+def parse_georss(element: Element) -> GeomDict:
+    """ Parses the GeoRSS basic elements to their respective GeoJSON
+        representation. As all coordinates in GeoRSS are expressed in
+        WGS84 and in Latitude/Longitude order, the coordinates are
+        swapped to XY order.
+
+        In case of georss:where, it is expected that it contains a
+        single GML element which is parsed as either GML 3.1.1, GML 3.2
+        or GML 3.3 CE.
+    """
+    qname = etree.QName(element.tag)
+    if qname.namespace != NAMESPACE:
+        raise ValueError(f'Unsupported namespace {qname.namespace}')
+
+    bbox = None
+    localname = qname.localname
+
+    if localname == 'point':
+        type_ = 'Point'
+        coordinates = swap_coordinate_xy(parse_pos(element.text))
+    elif localname == 'line':
+        type_ = 'LineString'
+        coordinates = swap_coordinates_xy(parse_poslist(element.text))
+    elif localname == 'box':
+        # boxes are expanded to Polygons, but store the 'bbox' value
+        type_ = 'Polygon'
+        low, high = swap_coordinates_xy(parse_poslist(element.text))
+        lx, ly = low
+        hx, hy = high
+        coordinates = [
+            [
+                (lx, ly),
+                (lx, hy),
+                (hx, hy),
+                (hx, ly),
+                (lx, ly),
+            ]
+        ]
+        bbox = (lx, ly, hx, hy)
+    elif localname == 'polygon':
+        type_ = 'Polygon'
+        coordinates = [swap_coordinates_xy(parse_poslist(element.text))]
+
+    elif localname == 'where':
+        # special handling here: defer to the gml definition. Although,
+        # only GML 3.1.1 is officially supported, we also allow GML 3.2 and 3.3
+        if not len(element) == 1:
+            raise ValueError(
+                'Invalid number of child elements in georss:where'
+            )
+        child = element[0]
+        child_namespace = etree.QName(child.tag).namespace
+
+        if child_namespace == NAMESPACE_PRE32:
+            return parse_pre_v32(child)
+        elif child_namespace == NAMESPACE_32:
+            return parse_v32(child)
+        elif child_namespace == NAMESPACE_33_CE:
+            return parse_v33_ce(child)
+        else:
+            raise ValueError(
+                f'Unsupported child element in georss:where: {child.tag}'
+            )
+    else:
+        raise ValueError(f'Unsupported georss element: {localname}')
+
+    result = {
+        'type': type_,
+        'coordinates': coordinates,
+    }
+    if bbox:
+        result['bbox'] = bbox
+
+    return result

pygml/parse.py

@@ -29,9 +29,10 @@
 from typing import Union
 from lxml import etree
 
-from .pre_v32 import parse_pre_v32
-from .v32 import parse_v32
-from .v33 import parse_v33_ce
+from .georss import NAMESPACE as NAMESPACE_GEORSS, parse_georss
+from .pre_v32 import NAMESPACE as NAMESPACE_PRE_v32, parse_pre_v32
+from .v32 import NAMESPACE as NAMESPACE_32, parse_v32
+from .v33 import NAMESPACE as NAMESPACE_33_CE, parse_v33_ce
 from .types import Geometry
 
 
@@ -45,11 +46,13 @@ def parse(source: Union[etree._Element, str]) -> Geometry:
         element = etree.fromstring(source)
 
     namespace = etree.QName(element.tag).namespace
-    if namespace == 'http://www.opengis.net/gml':
+    if namespace == NAMESPACE_PRE_v32:
         result = parse_pre_v32(element)
-    elif namespace == 'http://www.opengis.net/gml/3.2':
+    elif namespace == NAMESPACE_32:
         result = parse_v32(element)
-    elif namespace == 'http://www.opengis.net/gml/3.3/ce':
+    elif namespace == NAMESPACE_33_CE:
         result = parse_v33_ce(element)
+    elif namespace == NAMESPACE_GEORSS:
+        result = parse_georss(element)
 
     return Geometry(result)

pygml/pre_v32.py

@@ -26,5 +26,9 @@
 # ------------------------------------------------------------------------------
 
 
+NAMESPACE = 'http://www.opengis.net/gml'
+NSMAP = {'gml': NAMESPACE}
+
+
 def parse_pre_v32():
     pass

pygml/v33.py

@@ -26,5 +26,9 @@
 # ------------------------------------------------------------------------------
 
 
+NAMESPACE = 'http://www.opengis.net/gml/3.3/ce'
+NSMAP = {'gmlce': NAMESPACE}
+
+
 def parse_v33_ce():
     pass

tests/test_georss.py

@@ -0,0 +1,113 @@
+# ------------------------------------------------------------------------------
+#
+# Project: pygml <https://github.com/geopython/pygml>
+# Authors: Fabian Schindler <[email protected]>
+#
+# ------------------------------------------------------------------------------
+# Copyright (C) 2021 EOX IT Services GmbH
+#
+# 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 of this Software or works derived from this 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.
+# ------------------------------------------------------------------------------
+
+
+from lxml import etree
+
+from pygml.georss import parse_georss
+
+
+def test_parse_point():
+    # basic test
+    result = parse_georss(
+        etree.fromstring("""
+            <georss:point xmlns:georss="http://www.georss.org/georss">
+                1.0 1.0
+            </georss:point>
+        """)
+    )
+    assert result == {'type': 'Point', 'coordinates': (1.0, 1.0)}
+
+
+def test_parse_line():
+    # basic test
+    result = parse_georss(
+        etree.fromstring("""
+            <georss:line xmlns:georss="http://www.georss.org/georss">
+                1.0 2.0 2.0 1.0
+            </georss:line>
+        """)
+    )
+    assert result == {
+        'type': 'LineString',
+        'coordinates': [
+            (2.0, 1.0),
+            (1.0, 2.0)
+        ]
+    }
+
+
+def test_parse_box():
+    # basic test
+    result = parse_georss(
+        etree.fromstring("""
+            <georss:box xmlns:georss="http://www.georss.org/georss">
+                1.0 0.5 2.0 1.5
+            </georss:box>
+        """)
+    )
+    assert result == {
+        'type': 'Polygon',
+        'bbox': (0.5, 1.0, 1.5, 2.0),
+        'coordinates': [
+            [
+                (0.5, 1.0),
+                (0.5, 2.0),
+                (1.5, 2.0),
+                (1.5, 1.0),
+                (0.5, 1.0)
+            ]
+        ]
+    }
+
+
+def test_parse_polygon():
+    # basic test
+    result = parse_georss(
+        etree.fromstring("""
+            <georss:polygon xmlns:georss="http://www.georss.org/georss">
+                1.0 0.5 2.0 0.5 2.0 1.5 1.0 1.5 1.0 0.5
+            </georss:polygon>
+        """)
+    )
+    assert result == {
+        'type': 'Polygon',
+        'coordinates': [
+            [
+                (0.5, 1.0),
+                (0.5, 2.0),
+                (1.5, 2.0),
+                (1.5, 1.0),
+                (0.5, 1.0)
+            ]
+        ]
+    }
+
+
+def test_parse_where():
+    # TODO: add tests as soon as gml 3.1 is done
+    pass