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	# 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	from __future__ import generators
11
12	__version__ = "$Revision$"
13	# $Source$
14	# $Id$
15
16	import os
17	import weakref
18	from math import ceil, log
19
20	import shapelib
21	import shptree
22	import table
23	import transientdb
24
25	from Thuban import _
26
27	# Shape type constants
28	SHAPETYPE_POLYGON = "polygon"
29	SHAPETYPE_ARC = "arc"
30	SHAPETYPE_POINT = "point"
31
32	# 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	#
38	# Raw shape data formats
39	#
40
41	# Raw data is the same as that returned by the points method.
42	RAW_PYTHON = "RAW_PYTHON"
43
44	# Raw data is a shapefile. The Shape object will use the shapeid as the
45	# raw data.
46	RAW_SHAPEFILE = "RAW_SHAPEFILE"
47
48	# Raw data in well-known text format
49	RAW_WKT = "RAW_WKT"
50
51
52	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	def compute_bbox(self):
61	"""
62	Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
63	"""
64	xs = []
65	ys = []
66	for part in self.Points():
67	for x, y in part:
68	xs.append(x)
69	ys.append(y)
70	return (min(xs), min(ys), max(xs), max(ys))
71
72	def ShapeID(self):
73	return self.shapeid
74
75	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
83	def RawData(self):
84	"""Return the shape id to use with the shapefile"""
85	return self.shapeid
86
87	def Shapefile(self):
88	"""Return the shapefile object"""
89	return self.shapefile
90
91
92	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	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	self.dbftable = table.DBFTable(filename)
129	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
130
131	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	def Table(self):
150	"""Return the table containing the attribute data"""
151	return self.table
152
153	def Shapefile(self):
154	"""Return the shapefile object"""
155	return self.shapefile
156
157	def FileName(self):
158	"""Return the filename used to open the shapefile"""
159	return self.filename
160
161	def FileType(self):
162	"""Return the filetype. This is always the string 'shapefile'"""
163	return "shapefile"
164
165	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	def RawShapeFormat(self):
173	"""Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
174	return RAW_SHAPEFILE
175
176	def NumShapes(self):
177	"""Return the number of shapes in the shape store"""
178	return self.numshapes
179
180	def Dependencies(self):
181	"""Return the empty tuple.
182
183	The ShapefileStore doesn't depend on anything else.
184	"""
185	return ()
186
187	def OrigShapeStore(self):
188	"""Return None.
189
190	The ShapefileStore was not derived from another shapestore.
191	"""
192	return None
193
194	def BoundingBox(self):
195	"""Return the bounding box of the shapes in the shapestore.
196
197	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	def ShapesInRegion(self, bbox):
203	"""Return an iterable over the shapes that overlap the bounding box.
204
205	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	"""
209	# Bind a few globals to locals to make it a bit faster
210	cls = ShapefileShape
211	shapefile = self.shapefile
212
213	left, bottom, right, top = bbox
214	for i in self.shapetree.find_shapes((left, bottom), (right, top)):
215	yield cls(shapefile, i)
216
217	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	def Shape(self, index):
223	"""Return the shape with index index"""
224	return ShapefileShape(self.shapefile, index)
225
226
227
228	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
238	Raises ValueError if the number of shapes in the shapestore
239	is different from the number of rows in the table.
240	"""
241
242	numShapes = shapestore.Shapefile().info()[0]
243	if numShapes != table.NumRows():
244	raise ValueError(_("Table not compatible with shapestore."))
245
246	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	"""Return the shapefile of the underlying shapestore"""
255	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	def OrigShapeStore(self):
262	"""
263	Return the original shapestore the derived store was instantiated with
264	"""
265	return self.shapestore
266
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	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	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	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	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