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 part in self.points:
            for x, y in part:
                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:
            points = []
            for poly in shape.vertices():
                part = []
                for x, y in poly:
                    part.append((x, y))
                points.append(part)

        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	bh	1551	for part in self.points:
52			for x, y in part:
53			xs.append(x)
54			ys.append(y)
55	bh	1535	self.llx = min(xs)
56			self.lly = min(ys)
57			self.urx = max(xs)
58			self.ury = max(ys)
59
60			self.bbox = (self.llx, self.lly, self.urx, self.ury)
61
62			return self.bbox
63
64			def Points(self):
65			return self.points
66
67
68
69	bh	984	class ShapeTable(transientdb.AutoTransientTable):
70
71			"""A Table that depends on a ShapefileStore
72
73			Intended use is by the ShapefileStore for the table associated with
74			the shapefiles.
75			"""
76
77			def __init__(self, store, db, table):
78			"""Initialize the ShapeTable.
79
80			Parameters:
81			store -- the ShapefileStore the table is to depend on
82			db -- The transient database to use
83			table -- the table
84			"""
85			transientdb.AutoTransientTable.__init__(self, db, table)
86			self.store = weakref.ref(store)
87
88			def Dependencies(self):
89			"""Return a tuple containing the shapestore"""
90			return (self.store(),)
91
92
93	bh	723	class ShapefileStore:
94
95			"""Combine a shapefile and the corresponding DBF file into one object"""
96
97			def __init__(self, session, filename):
98			# Make the filename absolute. The filename will be
99			# interpreted relative to that anyway, but when saving a
100			# session we need to compare absolute paths and it's usually
101			# safer to always work with absolute paths.
102			self.filename = os.path.abspath(filename)
103
104			self.shapefile = shapelib.ShapeFile(self.filename)
105	bh	765	self.dbftable = table.DBFTable(filename)
106	bh	984	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
107	bh	723
108	bh	1535	self.numshapes, shapetype, mins, maxs = self.shapefile.info()
109			if self.numshapes:
110			self.bbox = mins[:2] + maxs[:2]
111			else:
112			self.bbox = None
113			self.shapetype = shapelib_shapetypes[shapetype]
114
115			# estimate a good depth for the quad tree. Each depth multiplies
116			# the number of nodes by four, therefore we basically take the
117			# base 4 logarithm of the number of shapes.
118			if self.numshapes < 4:
119			maxdepth = 1
120			else:
121			maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
122
123			self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
124			maxdepth)
125
126	bh	723	def Table(self):
127	bh	984	"""Return the table containing the attribute data"""
128	bh	723	return self.table
129
130			def Shapefile(self):
131	bh	984	"""Return the shapefile object"""
132	bh	723	return self.shapefile
133	bh	765
134	bh	984	def FileName(self):
135			"""Return the filename used to open the shapefile"""
136			return self.filename
137	bh	765
138	bh	984	def FileType(self):
139			"""Return the filetype. This is always the string 'shapefile'"""
140			return "shapefile"
141
142	bh	1535	def ShapeType(self):
143			"""Return the type of the shapes in the shapestore.
144
145			This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
146			"""
147			return self.shapetype
148
149			def NumShapes(self):
150			"""Return the number of shapes in the shape store"""
151			return self.numshapes
152
153	bh	984	def Dependencies(self):
154			"""Return the empty tuple.
155
156			The ShapefileStore doesn't depend on anything else.
157			"""
158			return ()
159
160	bh	1074	def OrigShapeStore(self):
161			"""Return None.
162	bh	984
163	bh	1074	The ShapefileStore was not derived from another shapestore.
164			"""
165			return None
166
167	bh	1535	def BoundingBox(self):
168			"""Return the bounding box of the shapes in the shapestore.
169	bh	1074
170	bh	1535	The coordinate system used is whatever was used in the shapefile.
171			If the shapefile is empty, return None.
172			"""
173			return self.bbox
174
175			def ShapesInRegion(self, box):
176			"""Return the ids of the shapes that overlap the box.
177
178			Box is a tuple (left, bottom, right, top) in the coordinate
179			system used used in the shapefile.
180			"""
181			left, bottom, right, top = box
182			return self.shapetree.find_shapes((left, bottom), (right, top))
183
184			def Shape(self, index):
185			"""Return the shape with index index"""
186			shape = self.shapefile.read_object(index)
187
188			if self.ShapeType() == SHAPETYPE_POINT:
189	bh	1551	points = [shape.vertices()]
190	bh	1535	else:
191			points = []
192	bh	1551	for poly in shape.vertices():
193			part = []
194			for x, y in poly:
195			part.append((x, y))
196			points.append(part)
197	bh	1535
198			return Shape(points)
199
200
201
202	bh	984	class DerivedShapeStore:
203
204			"""A ShapeStore derived from other shapestores or tables"""
205
206			def __init__(self, shapestore, table):
207			"""Initialize the derived shapestore.
208
209			The arguments are a shapestore for the shapedata and a table for
210			the tabular data.
211	jonathan	1261
212			Raises ValueError if the number of shapes in the shapestore
213			is different from the number of rows in the table.
214	bh	984	"""
215	jonathan	1261
216			numShapes = shapestore.Shapefile().info()[0]
217			if numShapes != table.NumRows():
218			raise ValueError(_("Table not compatible with shapestore."))
219
220	bh	984	self.shapestore = shapestore
221			self.table = table
222
223			def Table(self):
224			"""Return the table"""
225			return self.table
226
227			def Shapefile(self):
228	bh	1074	"""Return the shapefile of the underlying shapestore"""
229	bh	984	return self.shapestore.Shapefile()
230
231			def Dependencies(self):
232			"""Return a tuple containing the shapestore and the table"""
233			return (self.shapestore, self.table)
234
235	bh	1074	def OrigShapeStore(self):
236			"""
237			Return the original shapestore the derived store was instantiated with
238			"""
239			return self.shapestore
240	bh	1535
241			def Shape(self, index):
242			"""Return the shape with index index"""
243			return self.shapestore.Shape(index)
244
245			def ShapesInRegion(self, bbox):
246			"""Return the ids of the shapes that overlap the box.
247
248			This method is simply delegated to the shapestore the
249			DerivedShapeStore was instantiated with.
250			"""
251			return self.shapestore.ShapesInRegion(bbox)
252
253			def ShapeType(self):
254			"""Return the type of the shapes in the layer.
255
256			This method is simply delegated to the shapestore the
257			DerivedShapeStore was instantiated with.
258			"""
259			return self.shapestore.ShapeType()
260
261			def NumShapes(self):
262			"""Return the number of shapes in the shapestore."""
263			return self.shapestore.NumShapes()
264
265			def BoundingBox(self):
266			"""Return the bounding box of the shapes in the shapestore.
267
268			This method is simply delegated to the shapestore the
269			DerivedShapeStore was instantiated with.
270			"""
271			return self.shapestore.BoundingBox()
Name	Value
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svn:keywords	Author Date Id Revision