from pathlib import Path
import os
+from steps.geometry_alias import ALIASES
+
class GeometryFactory:
- """ Provides functions to create geometries from scenes and data grids.
+ """ Provides functions to create geometries from coordinates and data grids.
"""
def __init__(self):
- defpath = Path(__file__) / '..' / '..' / '..' / 'scenes' / 'data'
- self.scene_path = os.environ.get('SCENE_PATH', defpath.resolve())
- self.scene_cache = {}
self.grid = {}
- def parse_geometry(self, geom, scene):
+ def parse_geometry(self, geom):
""" Create a WKT SQL term for the given geometry.
The function understands the following formats:
- [<scene>]:<name>
- Geometry from a scene. If the scene is omitted, use the
- default scene.
+ country:<country code>
+ Point geometry guaranteed to be in the given country
<P>
Point geometry
<P>,...,<P>
number. In the latter case it must refer to a point in
a previously defined grid.
"""
- if geom.find(':') >= 0:
- return "ST_SetSRID({}, 4326)".format(self.get_scene_geometry(scene, geom))
+ if geom.startswith('country:'):
+ ccode = geom[8:].upper()
+ assert ccode in ALIASES, "Geometry error: unknown country " + ccode
+ return "ST_SetSRID('POINT({} {})'::geometry, 4326)".format(*ALIASES[ccode])
if geom.find(',') < 0:
out = "POINT({})".format(self.mk_wkt_point(geom))
return "ST_SetSRID('{}'::geometry, 4326)".format(out)
+
def mk_wkt_point(self, point):
""" Parse a point description.
- The point may either consist of 'x y' cooordinates or a number
+ The point may either consist of 'x y' coordinates or a number
that refers to a grid setup.
"""
geom = point.strip()
assert pt is not None, "Scenario error: Point '{}' not found in grid".format(geom)
return "{} {}".format(*pt)
+
def mk_wkt_points(self, geom):
""" Parse a list of points.
The list must be a comma-separated list of points. Points
"""
return ','.join([self.mk_wkt_point(x) for x in geom.split(',')])
- def get_scene_geometry(self, default_scene, name):
- """ Load the geometry from a scene.
- """
- geoms = []
- for obj in name.split('+'):
- oname = obj.strip()
- if oname.startswith(':'):
- assert default_scene is not None, "Scenario error: You need to set a scene"
- defscene = self.load_scene(default_scene)
- wkt = defscene[oname[1:]]
- else:
- scene, obj = oname.split(':', 2)
- scene_geoms = self.load_scene(scene)
- wkt = scene_geoms[obj]
-
- geoms.append("'{}'::geometry".format(wkt))
-
- if len(geoms) == 1:
- return geoms[0]
-
- return 'ST_LineMerge(ST_Collect(ARRAY[{}]))'.format(','.join(geoms))
-
- def load_scene(self, name):
- """ Load a scene from a file.
- """
- if name in self.scene_cache:
- return self.scene_cache[name]
-
- scene = {}
- with open(Path(self.scene_path) / "{}.wkt".format(name), 'r') as fd:
- for line in fd:
- if line.strip():
- obj, wkt = line.split('|', 2)
- scene[obj.strip()] = wkt.strip()
- self.scene_cache[name] = scene
-
- return scene
def set_grid(self, lines, grid_step, origin=(0.0, 0.0)):
""" Replace the grid with one from the given lines.
x += grid_step
y += grid_step
+
def grid_node(self, nodeid):
""" Get the coordinates for the given grid node.
"""