Thuban/Model/data.py

# Copyright (C) 2003 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with the software for details.

"""Data source abstractions"""

__version__ = "$Revision$"
# $Source$
# $Id$

import os
import weakref
from math import ceil, log

import shapelib
import shptree
import table
import transientdb

from Thuban import _

# Shape type constants
SHAPETYPE_POLYGON = "polygon"
SHAPETYPE_ARC = "arc"
SHAPETYPE_POINT = "point"

# mapping from shapelib shapetype constants to our constants
shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
                       shapelib.SHPT_ARC: SHAPETYPE_ARC,
                       shapelib.SHPT_POINT: SHAPETYPE_POINT}


class Shape:

    """Represent one shape"""

    def __init__(self, points):
        self.points = points
        #self.compute_bbox()
        self.bbox = None

    def compute_bbox(self):
        if self.bbox is not None:
            return self.bbox

        xs = []
        ys = []
        for x, y in self.points:
            xs.append(x)
            ys.append(y)
        self.llx = min(xs)
        self.lly = min(ys)
        self.urx = max(xs)
        self.ury = max(ys)

        self.bbox = (self.llx, self.lly, self.urx, self.ury)

        return self.bbox

    def Points(self):
        return self.points


class ShapeTable(transientdb.AutoTransientTable):

    """A Table that depends on a ShapefileStore

    Intended use is by the ShapefileStore for the table associated with
    the shapefiles.
    """

    def __init__(self, store, db, table):
        """Initialize the ShapeTable.

        Parameters:
            store -- the ShapefileStore the table is to depend on
            db -- The transient database to use
            table -- the table
        """
        transientdb.AutoTransientTable.__init__(self, db, table)
        self.store = weakref.ref(store)

    def Dependencies(self):
        """Return a tuple containing the shapestore"""
        return (self.store(),)


class ShapefileStore:

    """Combine a shapefile and the corresponding DBF file into one object"""

    def __init__(self, session, filename):
        # Make the filename absolute. The filename will be
        # interpreted relative to that anyway, but when saving a
        # session we need to compare absolute paths and it's usually
        # safer to always work with absolute paths.
        self.filename = os.path.abspath(filename)

        self.shapefile = shapelib.ShapeFile(self.filename)
        self.dbftable = table.DBFTable(filename)
        self.table = ShapeTable(self, session.TransientDB(), self.dbftable)

        self.numshapes, shapetype, mins, maxs = self.shapefile.info()
        if self.numshapes:
            self.bbox = mins[:2] + maxs[:2]
        else:
            self.bbox = None
        self.shapetype = shapelib_shapetypes[shapetype]

        # estimate a good depth for the quad tree. Each depth multiplies
        # the number of nodes by four, therefore we basically take the
        # base 4 logarithm of the number of shapes.
        if self.numshapes < 4:
            maxdepth = 1
        else:
            maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))

        self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
                                         maxdepth)

    def Table(self):
        """Return the table containing the attribute data"""
        return self.table

    def Shapefile(self):
        """Return the shapefile object"""
        return self.shapefile

    def FileName(self):
        """Return the filename used to open the shapefile"""
        return self.filename

    def FileType(self):
        """Return the filetype. This is always the string 'shapefile'"""
        return "shapefile"

    def ShapeType(self):
        """Return the type of the shapes in the shapestore.

        This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
        """
        return self.shapetype

    def NumShapes(self):
        """Return the number of shapes in the shape store"""
        return self.numshapes

    def Dependencies(self):
        """Return the empty tuple.

        The ShapefileStore doesn't depend on anything else.
        """
        return ()

    def OrigShapeStore(self):
        """Return None.

        The ShapefileStore was not derived from another shapestore.
        """
        return None

    def BoundingBox(self):
        """Return the bounding box of the shapes in the shapestore.

        The coordinate system used is whatever was used in the shapefile.
        If the shapefile is empty, return None.
        """
        return self.bbox

    def ShapesInRegion(self, box):
        """Return the ids of the shapes that overlap the box.

        Box is a tuple (left, bottom, right, top) in the coordinate
        system used used in the shapefile.
        """
        left, bottom, right, top = box
        return self.shapetree.find_shapes((left, bottom), (right, top))

    def Shape(self, index):
        """Return the shape with index index"""
        shape = self.shapefile.read_object(index)

        if self.ShapeType() == SHAPETYPE_POINT:
            points = shape.vertices()
        else:
            #for poly in shape.vertices():
            poly = shape.vertices()[0]
            points = []
            for x, y in poly:
                points.append((x, y))

        return Shape(points)


class DerivedShapeStore:

    """A ShapeStore derived from other shapestores or tables"""

    def __init__(self, shapestore, table):
        """Initialize the derived shapestore.

        The arguments are a shapestore for the shapedata and a table for
        the tabular data.

        Raises ValueError if the number of shapes in the shapestore
        is different from the number of rows in the table.
        """

        numShapes = shapestore.Shapefile().info()[0]
        if numShapes != table.NumRows():
            raise ValueError(_("Table not compatible with shapestore."))

        self.shapestore = shapestore
        self.table = table

    def Table(self):
        """Return the table"""
        return self.table

    def Shapefile(self):
        """Return the shapefile of the underlying shapestore"""
        return self.shapestore.Shapefile()

    def Dependencies(self):
        """Return a tuple containing the shapestore and the table"""
        return (self.shapestore, self.table)

    def OrigShapeStore(self):
        """
        Return the original shapestore the derived store was instantiated with
        """
        return self.shapestore

    def Shape(self, index):
        """Return the shape with index index"""
        return self.shapestore.Shape(index)

    def ShapesInRegion(self, bbox):
        """Return the ids of the shapes that overlap the box.

        This method is simply delegated to the shapestore the
        DerivedShapeStore was instantiated with.
        """
        return self.shapestore.ShapesInRegion(bbox)

    def ShapeType(self):
        """Return the type of the shapes in the layer.

        This method is simply delegated to the shapestore the
        DerivedShapeStore was instantiated with.
        """
        return self.shapestore.ShapeType()

    def NumShapes(self):
        """Return the number of shapes in the shapestore."""
        return self.shapestore.NumShapes()

    def BoundingBox(self):
        """Return the bounding box of the shapes in the shapestore.

        This method is simply delegated to the shapestore the
        DerivedShapeStore was instantiated with.
        """
        return self.shapestore.BoundingBox()
1	bh	723	# Copyright (C) 2003 by Intevation GmbH
2			# Authors:
3			# Bernhard Herzog <[email protected]>
4			#
5			# This program is free software under the GPL (>=v2)
6			# Read the file COPYING coming with the software for details.
7
8			"""Data source abstractions"""
9
10			__version__ = "$Revision$"
11			# $Source$
12			# $Id$
13
14			import os
15	bh	984	import weakref
16	bh	1535	from math import ceil, log
17	bh	723
18			import shapelib
19	bh	1535	import shptree
20	bh	723	import table
21	bh	765	import transientdb
22	bh	723
23	jonathan	1261	from Thuban import _
24	bh	765
25	bh	1535	# Shape type constants
26			SHAPETYPE_POLYGON = "polygon"
27			SHAPETYPE_ARC = "arc"
28			SHAPETYPE_POINT = "point"
29	jonathan	1261
30	bh	1535	# mapping from shapelib shapetype constants to our constants
31			shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
32			shapelib.SHPT_ARC: SHAPETYPE_ARC,
33			shapelib.SHPT_POINT: SHAPETYPE_POINT}
34
35
36			class Shape:
37
38			"""Represent one shape"""
39
40			def __init__(self, points):
41			self.points = points
42			#self.compute_bbox()
43			self.bbox = None
44
45			def compute_bbox(self):
46			if self.bbox is not None:
47			return self.bbox
48
49			xs = []
50			ys = []
51			for x, y in self.points:
52			xs.append(x)
53			ys.append(y)
54			self.llx = min(xs)
55			self.lly = min(ys)
56			self.urx = max(xs)
57			self.ury = max(ys)
58
59			self.bbox = (self.llx, self.lly, self.urx, self.ury)
60
61			return self.bbox
62
63			def Points(self):
64			return self.points
65
66
67
68	bh	984	class ShapeTable(transientdb.AutoTransientTable):
69
70			"""A Table that depends on a ShapefileStore
71
72			Intended use is by the ShapefileStore for the table associated with
73			the shapefiles.
74			"""
75
76			def __init__(self, store, db, table):
77			"""Initialize the ShapeTable.
78
79			Parameters:
80			store -- the ShapefileStore the table is to depend on
81			db -- The transient database to use
82			table -- the table
83			"""
84			transientdb.AutoTransientTable.__init__(self, db, table)
85			self.store = weakref.ref(store)
86
87			def Dependencies(self):
88			"""Return a tuple containing the shapestore"""
89			return (self.store(),)
90
91
92	bh	723	class ShapefileStore:
93
94			"""Combine a shapefile and the corresponding DBF file into one object"""
95
96			def __init__(self, session, filename):
97			# Make the filename absolute. The filename will be
98			# interpreted relative to that anyway, but when saving a
99			# session we need to compare absolute paths and it's usually
100			# safer to always work with absolute paths.
101			self.filename = os.path.abspath(filename)
102
103			self.shapefile = shapelib.ShapeFile(self.filename)
104	bh	765	self.dbftable = table.DBFTable(filename)
105	bh	984	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
106	bh	723
107	bh	1535	self.numshapes, shapetype, mins, maxs = self.shapefile.info()
108			if self.numshapes:
109			self.bbox = mins[:2] + maxs[:2]
110			else:
111			self.bbox = None
112			self.shapetype = shapelib_shapetypes[shapetype]
113
114			# estimate a good depth for the quad tree. Each depth multiplies
115			# the number of nodes by four, therefore we basically take the
116			# base 4 logarithm of the number of shapes.
117			if self.numshapes < 4:
118			maxdepth = 1
119			else:
120			maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
121
122			self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
123			maxdepth)
124
125	bh	723	def Table(self):
126	bh	984	"""Return the table containing the attribute data"""
127	bh	723	return self.table
128
129			def Shapefile(self):
130	bh	984	"""Return the shapefile object"""
131	bh	723	return self.shapefile
132	bh	765
133	bh	984	def FileName(self):
134			"""Return the filename used to open the shapefile"""
135			return self.filename
136	bh	765
137	bh	984	def FileType(self):
138			"""Return the filetype. This is always the string 'shapefile'"""
139			return "shapefile"
140
141	bh	1535	def ShapeType(self):
142			"""Return the type of the shapes in the shapestore.
143
144			This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
145			"""
146			return self.shapetype
147
148			def NumShapes(self):
149			"""Return the number of shapes in the shape store"""
150			return self.numshapes
151
152	bh	984	def Dependencies(self):
153			"""Return the empty tuple.
154
155			The ShapefileStore doesn't depend on anything else.
156			"""
157			return ()
158
159	bh	1074	def OrigShapeStore(self):
160			"""Return None.
161	bh	984
162	bh	1074	The ShapefileStore was not derived from another shapestore.
163			"""
164			return None
165
166	bh	1535	def BoundingBox(self):
167			"""Return the bounding box of the shapes in the shapestore.
168	bh	1074
169	bh	1535	The coordinate system used is whatever was used in the shapefile.
170			If the shapefile is empty, return None.
171			"""
172			return self.bbox
173
174			def ShapesInRegion(self, box):
175			"""Return the ids of the shapes that overlap the box.
176
177			Box is a tuple (left, bottom, right, top) in the coordinate
178			system used used in the shapefile.
179			"""
180			left, bottom, right, top = box
181			return self.shapetree.find_shapes((left, bottom), (right, top))
182
183			def Shape(self, index):
184			"""Return the shape with index index"""
185			shape = self.shapefile.read_object(index)
186
187			if self.ShapeType() == SHAPETYPE_POINT:
188			points = shape.vertices()
189			else:
190			#for poly in shape.vertices():
191			poly = shape.vertices()[0]
192			points = []
193			for x, y in poly:
194			points.append((x, y))
195
196			return Shape(points)
197
198
199
200	bh	984	class DerivedShapeStore:
201
202			"""A ShapeStore derived from other shapestores or tables"""
203
204			def __init__(self, shapestore, table):
205			"""Initialize the derived shapestore.
206
207			The arguments are a shapestore for the shapedata and a table for
208			the tabular data.
209	jonathan	1261
210			Raises ValueError if the number of shapes in the shapestore
211			is different from the number of rows in the table.
212	bh	984	"""
213	jonathan	1261
214			numShapes = shapestore.Shapefile().info()[0]
215			if numShapes != table.NumRows():
216			raise ValueError(_("Table not compatible with shapestore."))
217
218	bh	984	self.shapestore = shapestore
219			self.table = table
220
221			def Table(self):
222			"""Return the table"""
223			return self.table
224
225			def Shapefile(self):
226	bh	1074	"""Return the shapefile of the underlying shapestore"""
227	bh	984	return self.shapestore.Shapefile()
228
229			def Dependencies(self):
230			"""Return a tuple containing the shapestore and the table"""
231			return (self.shapestore, self.table)
232
233	bh	1074	def OrigShapeStore(self):
234			"""
235			Return the original shapestore the derived store was instantiated with
236			"""
237			return self.shapestore
238	bh	1535
239			def Shape(self, index):
240			"""Return the shape with index index"""
241			return self.shapestore.Shape(index)
242
243			def ShapesInRegion(self, bbox):
244			"""Return the ids of the shapes that overlap the box.
245
246			This method is simply delegated to the shapestore the
247			DerivedShapeStore was instantiated with.
248			"""
249			return self.shapestore.ShapesInRegion(bbox)
250
251			def ShapeType(self):
252			"""Return the type of the shapes in the layer.
253
254			This method is simply delegated to the shapestore the
255			DerivedShapeStore was instantiated with.
256			"""
257			return self.shapestore.ShapeType()
258
259			def NumShapes(self):
260			"""Return the number of shapes in the shapestore."""
261			return self.shapestore.NumShapes()
262
263			def BoundingBox(self):
264			"""Return the bounding box of the shapes in the shapestore.
265
266			This method is simply delegated to the shapestore the
267			DerivedShapeStore was instantiated with.
268			"""
269			return self.shapestore.BoundingBox()
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision