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.dbftable = table.DBFTable(filename)
        self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
        self._open_shapefile()

    def _open_shapefile(self):
        self.shapefile = shapelib.ShapeFile(self.filename)
        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.dbftable = table.DBFTable(filename)
128	self.table = ShapeTable(self, session.TransientDB(), self.dbftable)
129	self._open_shapefile()
130
131	def _open_shapefile(self):
132	self.shapefile = shapelib.ShapeFile(self.filename)
133	self.numshapes, shapetype, mins, maxs = self.shapefile.info()
134	if self.numshapes:
135	self.bbox = mins[:2] + maxs[:2]
136	else:
137	self.bbox = None
138	self.shapetype = shapelib_shapetypes[shapetype]
139
140	# estimate a good depth for the quad tree. Each depth multiplies
141	# the number of nodes by four, therefore we basically take the
142	# base 4 logarithm of the number of shapes.
143	if self.numshapes < 4:
144	maxdepth = 1
145	else:
146	maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
147
148	self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
149	maxdepth)
150
151	def Table(self):
152	"""Return the table containing the attribute data"""
153	return self.table
154
155	def Shapefile(self):
156	"""Return the shapefile object"""
157	return self.shapefile
158
159	def FileName(self):
160	"""Return the filename used to open the shapefile"""
161	return self.filename
162
163	def FileType(self):
164	"""Return the filetype. This is always the string 'shapefile'"""
165	return "shapefile"
166
167	def ShapeType(self):
168	"""Return the type of the shapes in the shapestore.
169
170	This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
171	"""
172	return self.shapetype
173
174	def RawShapeFormat(self):
175	"""Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
176	return RAW_SHAPEFILE
177
178	def NumShapes(self):
179	"""Return the number of shapes in the shape store"""
180	return self.numshapes
181
182	def Dependencies(self):
183	"""Return the empty tuple.
184
185	The ShapefileStore doesn't depend on anything else.
186	"""
187	return ()
188
189	def OrigShapeStore(self):
190	"""Return None.
191
192	The ShapefileStore was not derived from another shapestore.
193	"""
194	return None
195
196	def BoundingBox(self):
197	"""Return the bounding box of the shapes in the shapestore.
198
199	The coordinate system used is whatever was used in the shapefile.
200	If the shapefile is empty, return None.
201	"""
202	return self.bbox
203
204	def ShapesInRegion(self, bbox):
205	"""Return an iterable over the shapes that overlap the bounding box.
206
207	The bbox parameter should be the bounding box as a tuple in the
208	form (minx, miny, maxx, maxy) in the coordinate system of the
209	shape store.
210	"""
211	# Bind a few globals to locals to make it a bit faster
212	cls = ShapefileShape
213	shapefile = self.shapefile
214
215	left, bottom, right, top = bbox
216	for i in self.shapetree.find_shapes((left, bottom), (right, top)):
217	yield cls(shapefile, i)
218
219	def AllShapes(self):
220	"""Return an iterable over the shapes in the shape store."""
221	for i in xrange(self.NumShapes()):
222	yield ShapefileShape(self.shapefile, i)
223
224	def Shape(self, index):
225	"""Return the shape with index index"""
226	return ShapefileShape(self.shapefile, index)
227
228
229
230	class DerivedShapeStore:
231
232	"""A ShapeStore derived from other shapestores or tables"""
233
234	def __init__(self, shapestore, table):
235	"""Initialize the derived shapestore.
236
237	The arguments are a shapestore for the shapedata and a table for
238	the tabular data.
239
240	Raises ValueError if the number of shapes in the shapestore
241	is different from the number of rows in the table.
242	"""
243
244	numShapes = shapestore.Shapefile().info()[0]
245	if numShapes != table.NumRows():
246	raise ValueError(_("Table not compatible with shapestore."))
247
248	self.shapestore = shapestore
249	self.table = table
250
251	def Table(self):
252	"""Return the table"""
253	return self.table
254
255	def Shapefile(self):
256	"""Return the shapefile of the underlying shapestore"""
257	return self.shapestore.Shapefile()
258
259	def Dependencies(self):
260	"""Return a tuple containing the shapestore and the table"""
261	return (self.shapestore, self.table)
262
263	def OrigShapeStore(self):
264	"""
265	Return the original shapestore the derived store was instantiated with
266	"""
267	return self.shapestore
268
269	def Shape(self, index):
270	"""Return the shape with index index"""
271	return self.shapestore.Shape(index)
272
273	def ShapesInRegion(self, bbox):
274	"""Return the ids of the shapes that overlap the box.
275
276	This method is simply delegated to the shapestore the
277	DerivedShapeStore was instantiated with.
278	"""
279	return self.shapestore.ShapesInRegion(bbox)
280
281	def AllShapes(self):
282	"""Return an iterable over the shapes in the shape store.
283
284	This method is simply delegated to the shapestore the
285	DerivedShapeStore was instantiated with.
286	"""
287	return self.shapestore.AllShapes()
288
289	def ShapeType(self):
290	"""Return the type of the shapes in the layer.
291
292	This method is simply delegated to the shapestore the
293	DerivedShapeStore was instantiated with.
294	"""
295	return self.shapestore.ShapeType()
296
297	def RawShapeFormat(self):
298	"""Return the raw data format of the shapes.
299
300	This method is simply delegated to the shapestore the
301	DerivedShapeStore was instantiated with.
302	"""
303	return self.shapestore.RawShapeFormat()
304
305	def NumShapes(self):
306	"""Return the number of shapes in the shapestore."""
307	return self.shapestore.NumShapes()
308
309	def BoundingBox(self):
310	"""Return the bounding box of the shapes in the shapestore.
311
312	This method is simply delegated to the shapestore the
313	DerivedShapeStore was instantiated with.
314	"""
315	return self.shapestore.BoundingBox()
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision