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"""

from __future__ import generators

__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}

#
# Raw shape data formats
#

# Raw data is the same as that returned by the points method.
RAW_PYTHON = "RAW_PYTHON"

# Raw data is a shapefile. The Shape object will use the shapeid as the
# raw data.
RAW_SHAPEFILE = "RAW_SHAPEFILE"

# Raw data in well-known text format
RAW_WKT = "RAW_WKT"


class ShapefileShape:

    """Represent one shape of a shapefile"""

    def __init__(self, shapefile, shapeid):
        self.shapefile = shapefile
        self.shapeid = shapeid

    def compute_bbox(self):
        """
        Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
        """
        xs = []
        ys = []
        for part in self.Points():
            for x, y in part:
                xs.append(x)
                ys.append(y)
        return (min(xs), min(ys), max(xs), max(ys))

    def ShapeID(self):
        return self.shapeid

    def Points(self):
        """Return the coordinates of the shape as a list of lists of pairs"""
        shape = self.shapefile.read_object(self.shapeid)
        points = shape.vertices()
        if self.shapefile.info()[1] == shapelib.SHPT_POINT:
            points = [points]
        return points

    def RawData(self):
        """Return the shape id to use with the shapefile"""
        return self.shapeid

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


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 RawShapeFormat(self):
        """Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
        return RAW_SHAPEFILE

    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, bbox):
        """Return an iterable over the shapes that overlap the bounding box.

        The bbox parameter should be the bounding box as a tuple in the
        form (minx, miny, maxx, maxy) in the coordinate system of the
        shape store.
        """
        # Bind a few globals to locals to make it a bit faster
        cls = ShapefileShape
        shapefile = self.shapefile

        left, bottom, right, top = bbox
        for i in self.shapetree.find_shapes((left, bottom), (right, top)):
            yield cls(shapefile, i)

    def AllShapes(self):
        """Return an iterable over the shapes in the shape store."""
        for i in xrange(self.NumShapes()):
            yield ShapefileShape(self.shapefile, i)

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


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 AllShapes(self):
        """Return an iterable over the shapes in the shape store.

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

    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 RawShapeFormat(self):
        """Return the raw data format of the shapes.

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

    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	bh	1593	from __future__ import generators
11
12	bh	723	__version__ = "$Revision$"
13			# $Source$
14			# $Id$
15
16			import os
17	bh	984	import weakref
18	bh	1535	from math import ceil, log
19	bh	723
20			import shapelib
21	bh	1535	import shptree
22	bh	723	import table
23	bh	765	import transientdb
24	bh	723
25	jonathan	1261	from Thuban import _
26	bh	765
27	bh	1535	# Shape type constants
28			SHAPETYPE_POLYGON = "polygon"
29			SHAPETYPE_ARC = "arc"
30			SHAPETYPE_POINT = "point"
31	jonathan	1261
32	bh	1535	# mapping from shapelib shapetype constants to our constants
33			shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
34			shapelib.SHPT_ARC: SHAPETYPE_ARC,
35			shapelib.SHPT_POINT: SHAPETYPE_POINT}
36
37	bh	1559	#
38			# Raw shape data formats
39			#
40	bh	1535
41	bh	1559	# Raw data is the same as that returned by the points method.
42			RAW_PYTHON = "RAW_PYTHON"
43	bh	1535
44	bh	1559	# Raw data is a shapefile. The Shape object will use the shapeid as the
45			# raw data.
46			RAW_SHAPEFILE = "RAW_SHAPEFILE"
47	bh	1535
48	bh	1605	# Raw data in well-known text format
49			RAW_WKT = "RAW_WKT"
50	bh	1535
51	bh	1605
52	bh	1559	class ShapefileShape:
53
54			"""Represent one shape of a shapefile"""
55
56			def __init__(self, shapefile, shapeid):
57			self.shapefile = shapefile
58			self.shapeid = shapeid
59
60	bh	1535	def compute_bbox(self):
61	bh	1559	"""
62			Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
63			"""
64	bh	1535	xs = []
65			ys = []
66	bh	1559	for part in self.Points():
67	bh	1551	for x, y in part:
68			xs.append(x)
69			ys.append(y)
70	bh	1559	return (min(xs), min(ys), max(xs), max(ys))
71	bh	1535
72	bh	1593	def ShapeID(self):
73			return self.shapeid
74
75	bh	1559	def Points(self):
76			"""Return the coordinates of the shape as a list of lists of pairs"""
77			shape = self.shapefile.read_object(self.shapeid)
78			points = shape.vertices()
79			if self.shapefile.info()[1] == shapelib.SHPT_POINT:
80			points = [points]
81			return points
82	bh	1535
83	bh	1559	def RawData(self):
84			"""Return the shape id to use with the shapefile"""
85			return self.shapeid
86	bh	1535
87	bh	1559	def Shapefile(self):
88			"""Return the shapefile object"""
89			return self.shapefile
90	bh	1535
91
92	bh	984	class ShapeTable(transientdb.AutoTransientTable):
93
94			"""A Table that depends on a ShapefileStore
95
96			Intended use is by the ShapefileStore for the table associated with
97			the shapefiles.
98			"""
99
100			def __init__(self, store, db, table):
101			"""Initialize the ShapeTable.
102
103			Parameters:
104			store -- the ShapefileStore the table is to depend on
105			db -- The transient database to use
106			table -- the table
107			"""
108			transientdb.AutoTransientTable.__init__(self, db, table)
109			self.store = weakref.ref(store)
110
111			def Dependencies(self):
112			"""Return a tuple containing the shapestore"""
113			return (self.store(),)
114
115
116	bh	723	class ShapefileStore:
117
118			"""Combine a shapefile and the corresponding DBF file into one object"""
119
120			def __init__(self, session, filename):
121			# Make the filename absolute. The filename will be
122			# interpreted relative to that anyway, but when saving a
123			# session we need to compare absolute paths and it's usually
124			# safer to always work with absolute paths.
125			self.filename = os.path.abspath(filename)
126
127			self.shapefile = shapelib.ShapeFile(self.filename)
128	bh	765	self.dbftable = table.DBFTable(filename)
129	bh	984	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
130	bh	723
131	bh	1535	self.numshapes, shapetype, mins, maxs = self.shapefile.info()
132			if self.numshapes:
133			self.bbox = mins[:2] + maxs[:2]
134			else:
135			self.bbox = None
136			self.shapetype = shapelib_shapetypes[shapetype]
137
138			# estimate a good depth for the quad tree. Each depth multiplies
139			# the number of nodes by four, therefore we basically take the
140			# base 4 logarithm of the number of shapes.
141			if self.numshapes < 4:
142			maxdepth = 1
143			else:
144			maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
145
146			self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
147			maxdepth)
148
149	bh	723	def Table(self):
150	bh	984	"""Return the table containing the attribute data"""
151	bh	723	return self.table
152
153			def Shapefile(self):
154	bh	984	"""Return the shapefile object"""
155	bh	723	return self.shapefile
156	bh	765
157	bh	984	def FileName(self):
158			"""Return the filename used to open the shapefile"""
159			return self.filename
160	bh	765
161	bh	984	def FileType(self):
162			"""Return the filetype. This is always the string 'shapefile'"""
163			return "shapefile"
164
165	bh	1535	def ShapeType(self):
166			"""Return the type of the shapes in the shapestore.
167
168			This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
169			"""
170			return self.shapetype
171
172	bh	1559	def RawShapeFormat(self):
173			"""Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
174			return RAW_SHAPEFILE
175
176	bh	1535	def NumShapes(self):
177			"""Return the number of shapes in the shape store"""
178			return self.numshapes
179
180	bh	984	def Dependencies(self):
181			"""Return the empty tuple.
182
183			The ShapefileStore doesn't depend on anything else.
184			"""
185			return ()
186
187	bh	1074	def OrigShapeStore(self):
188			"""Return None.
189	bh	984
190	bh	1074	The ShapefileStore was not derived from another shapestore.
191			"""
192			return None
193
194	bh	1535	def BoundingBox(self):
195			"""Return the bounding box of the shapes in the shapestore.
196	bh	1074
197	bh	1535	The coordinate system used is whatever was used in the shapefile.
198			If the shapefile is empty, return None.
199			"""
200			return self.bbox
201
202	bh	1593	def ShapesInRegion(self, bbox):
203			"""Return an iterable over the shapes that overlap the bounding box.
204	bh	1535
205	bh	1593	The bbox parameter should be the bounding box as a tuple in the
206			form (minx, miny, maxx, maxy) in the coordinate system of the
207			shape store.
208	bh	1535	"""
209	bh	1921	# Bind a few globals to locals to make it a bit faster
210			cls = ShapefileShape
211			shapefile = self.shapefile
212
213	bh	1593	left, bottom, right, top = bbox
214			for i in self.shapetree.find_shapes((left, bottom), (right, top)):
215	bh	1921	yield cls(shapefile, i)
216	bh	1535
217	bh	1593	def AllShapes(self):
218			"""Return an iterable over the shapes in the shape store."""
219			for i in xrange(self.NumShapes()):
220			yield ShapefileShape(self.shapefile, i)
221
222	bh	1535	def Shape(self, index):
223			"""Return the shape with index index"""
224	bh	1559	return ShapefileShape(self.shapefile, index)
225	bh	1535
226
227
228	bh	984	class DerivedShapeStore:
229
230			"""A ShapeStore derived from other shapestores or tables"""
231
232			def __init__(self, shapestore, table):
233			"""Initialize the derived shapestore.
234
235			The arguments are a shapestore for the shapedata and a table for
236			the tabular data.
237	jonathan	1261
238			Raises ValueError if the number of shapes in the shapestore
239			is different from the number of rows in the table.
240	bh	984	"""
241	jonathan	1261
242			numShapes = shapestore.Shapefile().info()[0]
243			if numShapes != table.NumRows():
244			raise ValueError(_("Table not compatible with shapestore."))
245
246	bh	984	self.shapestore = shapestore
247			self.table = table
248
249			def Table(self):
250			"""Return the table"""
251			return self.table
252
253			def Shapefile(self):
254	bh	1074	"""Return the shapefile of the underlying shapestore"""
255	bh	984	return self.shapestore.Shapefile()
256
257			def Dependencies(self):
258			"""Return a tuple containing the shapestore and the table"""
259			return (self.shapestore, self.table)
260
261	bh	1074	def OrigShapeStore(self):
262			"""
263			Return the original shapestore the derived store was instantiated with
264			"""
265			return self.shapestore
266	bh	1535
267			def Shape(self, index):
268			"""Return the shape with index index"""
269			return self.shapestore.Shape(index)
270
271			def ShapesInRegion(self, bbox):
272			"""Return the ids of the shapes that overlap the box.
273
274			This method is simply delegated to the shapestore the
275			DerivedShapeStore was instantiated with.
276			"""
277			return self.shapestore.ShapesInRegion(bbox)
278
279	bh	1593	def AllShapes(self):
280			"""Return an iterable over the shapes in the shape store.
281
282			This method is simply delegated to the shapestore the
283			DerivedShapeStore was instantiated with.
284			"""
285			return self.shapestore.AllShapes()
286
287	bh	1535	def ShapeType(self):
288			"""Return the type of the shapes in the layer.
289
290			This method is simply delegated to the shapestore the
291			DerivedShapeStore was instantiated with.
292			"""
293			return self.shapestore.ShapeType()
294
295	bh	1564	def RawShapeFormat(self):
296			"""Return the raw data format of the shapes.
297
298			This method is simply delegated to the shapestore the
299			DerivedShapeStore was instantiated with.
300			"""
301			return self.shapestore.RawShapeFormat()
302
303	bh	1535	def NumShapes(self):
304			"""Return the number of shapes in the shapestore."""
305			return self.shapestore.NumShapes()
306
307			def BoundingBox(self):
308			"""Return the bounding box of the shapes in the shapestore.
309
310			This method is simply delegated to the shapestore the
311			DerivedShapeStore was instantiated with.
312			"""
313			return self.shapestore.BoundingBox()
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision