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}

#
# 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"


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