Thuban/Model/data.py

# Copyright (C) 2003, 2005 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(),)

# XXX: (this statement should be kept in mind when re-engeneering)
#
# From a desing POV it was wrong to distinguish between table and
# shapestore.  In hindsight the only reason for doing so was that the
# shapelib has different objects for the shapefile(s) and the dbf file,
# which of course matches the way the data is organized into different
# files.  So the distinction between shapestore and table is an artifact
# of the shapefile format.  When we added the postgis support we should
# have adopted the table interface for the entire shape store, making the
# geometry data an additional column for those shape stores that don't
# store the geometries in columns in the first place.

class FileShapeStore:

    """The base class to derive any file-based ShapeStore from.

    This class contains all information that is needed by a
    loader routine to actually load the shapestore.
    This essentially means that the class contains all required information
    to save the shapestore specification (i.e. in a .thuban file).
    """

    def __init__(self, filename, sublayer_name = None):
        """Initialize the base class with main parameters.

        filename  -- the source filename.
                     This filename will be converted to an absolute filename.
                     The filename will be interpreted relative to the .thuban file anyway,
                     but when saving a session we need to compare absolute paths
                     and it's usually safer to always work with absolute paths.
        sublayer_name -- a string representing a layer within the file shape store.
                     Some file formats support to contain several layers, or
                     at least the ogr library says so.
                     For those filetypes who don't, the sublayer_name can be ignored
                     and by default it is None.
        """
        self._filename = os.path.abspath(filename)
        self._sublayer_name = sublayer_name

    def FileName(self):
        """Return the filename used to open the shapestore.

        The filename can only be set via __init__ method.
        """
        return self._filename

    def FileType(self):
        """Return the filetype.

        The filetype has to be set in all derived classes.
        It must be string.
        Known and used types are: "shapefile"
        """
        raise NotImplementedError

    def SublayerName(self):
        """Return the sublayer_name.

        This could be None if the shapestore type only supports a single
        layer.
        """
        return self._sublayer_name

    # Design/Implementation note:
    # It is not a good idea to have a implementation for a
    # "setBoundingBox" or BoundingBox in this base class.
    # In future this data might change during
    # a Thuban session and thus can not be kept statically here.
    # It is expected that for many derived classes the bbox must
    # be retrieved each time anew.

    def BoundingBox(self):
        """Return the bounding box of the shapes in the shape store.

        The coordinate system used is whatever was used in the shape store.
        If the shape store is empty, return None.
        """
        raise NotImplementedError

class ShapefileStore(FileShapeStore):

    """Combine a shapefile and the corresponding DBF file into one object"""

    def __init__(self, session, filename):
        FileShapeStore.__init__(self, filename)

        self.dbftable = table.DBFTable(filename)
        self._table = ShapeTable(self, session.TransientDB(), self.dbftable)
        self._bbox = None
        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 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 shapefile"""
        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 shapefile.

        The coordinate system used is whatever was used in the shapefile.
        If the shapefileis 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
        shapefile.
        """
        # 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 shapefile."""
        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 shapefile.

        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, 2005 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	# XXX: (this statement should be kept in mind when re-engeneering)
116	#
117	# From a desing POV it was wrong to distinguish between table and
118	# shapestore. In hindsight the only reason for doing so was that the
119	# shapelib has different objects for the shapefile(s) and the dbf file,
120	# which of course matches the way the data is organized into different
121	# files. So the distinction between shapestore and table is an artifact
122	# of the shapefile format. When we added the postgis support we should
123	# have adopted the table interface for the entire shape store, making the
124	# geometry data an additional column for those shape stores that don't
125	# store the geometries in columns in the first place.
126
127	class FileShapeStore:
128
129	"""The base class to derive any file-based ShapeStore from.
130
131	This class contains all information that is needed by a
132	loader routine to actually load the shapestore.
133	This essentially means that the class contains all required information
134	to save the shapestore specification (i.e. in a .thuban file).
135	"""
136
137	def __init__(self, filename, sublayer_name = None):
138	"""Initialize the base class with main parameters.
139
140	filename -- the source filename.
141	This filename will be converted to an absolute filename.
142	The filename will be interpreted relative to the .thuban file anyway,
143	but when saving a session we need to compare absolute paths
144	and it's usually safer to always work with absolute paths.
145	sublayer_name -- a string representing a layer within the file shape store.
146	Some file formats support to contain several layers, or
147	at least the ogr library says so.
148	For those filetypes who don't, the sublayer_name can be ignored
149	and by default it is None.
150	"""
151	self._filename = os.path.abspath(filename)
152	self._sublayer_name = sublayer_name
153
154	def FileName(self):
155	"""Return the filename used to open the shapestore.
156
157	The filename can only be set via __init__ method.
158	"""
159	return self._filename
160
161	def FileType(self):
162	"""Return the filetype.
163
164	The filetype has to be set in all derived classes.
165	It must be string.
166	Known and used types are: "shapefile"
167	"""
168	raise NotImplementedError
169
170	def SublayerName(self):
171	"""Return the sublayer_name.
172
173	This could be None if the shapestore type only supports a single
174	layer.
175	"""
176	return self._sublayer_name
177
178	# Design/Implementation note:
179	# It is not a good idea to have a implementation for a
180	# "setBoundingBox" or BoundingBox in this base class.
181	# In future this data might change during
182	# a Thuban session and thus can not be kept statically here.
183	# It is expected that for many derived classes the bbox must
184	# be retrieved each time anew.
185
186	def BoundingBox(self):
187	"""Return the bounding box of the shapes in the shape store.
188
189	The coordinate system used is whatever was used in the shape store.
190	If the shape store is empty, return None.
191	"""
192	raise NotImplementedError
193
194	class ShapefileStore(FileShapeStore):
195
196	"""Combine a shapefile and the corresponding DBF file into one object"""
197
198	def __init__(self, session, filename):
199	FileShapeStore.__init__(self, filename)
200
201	self.dbftable = table.DBFTable(filename)
202	self._table = ShapeTable(self, session.TransientDB(), self.dbftable)
203	self._bbox = None
204	self._open_shapefile()
205
206	def _open_shapefile(self):
207	self.shapefile = shapelib.ShapeFile(self.FileName())
208	self.numshapes, shapetype, mins, maxs = self.shapefile.info()
209	if self.numshapes:
210	self._bbox = mins[:2] + maxs[:2]
211	else:
212	self._bbox = None
213	self.shapetype = shapelib_shapetypes[shapetype]
214
215	# estimate a good depth for the quad tree. Each depth multiplies
216	# the number of nodes by four, therefore we basically take the
217	# base 4 logarithm of the number of shapes.
218	if self.numshapes < 4:
219	maxdepth = 1
220	else:
221	maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
222
223	self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
224	maxdepth)
225
226	def Table(self):
227	"""Return the table containing the attribute data."""
228	return self._table
229
230	def Shapefile(self):
231	"""Return the shapefile object"""
232	return self.shapefile
233
234	def FileType(self):
235	"""Return the filetype. This is always the string 'shapefile'"""
236	return "shapefile"
237
238	def ShapeType(self):
239	"""Return the type of the shapes in the shapestore.
240
241	This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
242	"""
243	return self.shapetype
244
245	def RawShapeFormat(self):
246	"""Return the raw data format of the shape data, i.e. RAW_SHAPEFILE"""
247	return RAW_SHAPEFILE
248
249	def NumShapes(self):
250	"""Return the number of shapes in the shapefile"""
251	return self.numshapes
252
253	def Dependencies(self):
254	"""Return the empty tuple.
255
256	The ShapefileStore doesn't depend on anything else.
257	"""
258	return ()
259
260	def OrigShapeStore(self):
261	"""Return None.
262
263	The ShapefileStore was not derived from another shapestore.
264	"""
265	return None
266
267	def BoundingBox(self):
268	"""Return the bounding box of the shapes in the shapefile.
269
270	The coordinate system used is whatever was used in the shapefile.
271	If the shapefileis empty, return None.
272	"""
273	return self._bbox
274
275	def ShapesInRegion(self, bbox):
276	"""Return an iterable over the shapes that overlap the bounding box.
277
278	The bbox parameter should be the bounding box as a tuple in the
279	form (minx, miny, maxx, maxy) in the coordinate system of the
280	shapefile.
281	"""
282	# Bind a few globals to locals to make it a bit faster
283	cls = ShapefileShape
284	shapefile = self.shapefile
285
286	left, bottom, right, top = bbox
287	for i in self.shapetree.find_shapes((left, bottom), (right, top)):
288	yield cls(shapefile, i)
289
290	def AllShapes(self):
291	"""Return an iterable over the shapes in the shapefile."""
292	for i in xrange(self.NumShapes()):
293	yield ShapefileShape(self.shapefile, i)
294
295	def Shape(self, index):
296	"""Return the shape with index index"""
297	return ShapefileShape(self.shapefile, index)
298
299
300	class DerivedShapeStore:
301
302	"""A ShapeStore derived from other shapestores or tables"""
303
304	def __init__(self, shapestore, table):
305	"""Initialize the derived shapestore.
306
307	The arguments are a shapestore for the shapedata and a table for
308	the tabular data.
309
310	Raises ValueError if the number of shapes in the shapestore
311	is different from the number of rows in the table.
312	"""
313
314	numShapes = shapestore.Shapefile().info()[0]
315	if numShapes != table.NumRows():
316	raise ValueError(_("Table not compatible with shapestore."))
317
318	self.shapestore = shapestore
319	self.table = table
320
321	def Table(self):
322	"""Return the table"""
323	return self.table
324
325	def Shapefile(self):
326	"""Return the shapefile of the underlying shapestore"""
327	return self.shapestore.Shapefile()
328
329	def Dependencies(self):
330	"""Return a tuple containing the shapestore and the table"""
331	return (self.shapestore, self.table)
332
333	def OrigShapeStore(self):
334	"""
335	Return the original shapestore the derived store was instantiated with
336	"""
337	return self.shapestore
338
339	def Shape(self, index):
340	"""Return the shape with index index"""
341	return self.shapestore.Shape(index)
342
343	def ShapesInRegion(self, bbox):
344	"""Return the ids of the shapes that overlap the box.
345
346	This method is simply delegated to the shapestore the
347	DerivedShapeStore was instantiated with.
348	"""
349	return self.shapestore.ShapesInRegion(bbox)
350
351	def AllShapes(self):
352	"""Return an iterable over the shapes in the shapefile.
353
354	This method is simply delegated to the shapestore the
355	DerivedShapeStore was instantiated with.
356	"""
357	return self.shapestore.AllShapes()
358
359	def ShapeType(self):
360	"""Return the type of the shapes in the layer.
361
362	This method is simply delegated to the shapestore the
363	DerivedShapeStore was instantiated with.
364	"""
365	return self.shapestore.ShapeType()
366
367	def RawShapeFormat(self):
368	"""Return the raw data format of the shapes.
369
370	This method is simply delegated to the shapestore the
371	DerivedShapeStore was instantiated with.
372	"""
373	return self.shapestore.RawShapeFormat()
374
375	def NumShapes(self):
376	"""Return the number of shapes in the shapestore."""
377	return self.shapestore.NumShapes()
378
379	def BoundingBox(self):
380	"""Return the bounding box of the shapes in the shapestore.
381
382	This method is simply delegated to the shapestore the
383	DerivedShapeStore was instantiated with.
384	"""
385	return self.shapestore.BoundingBox()
Name	Value
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svn:keywords	Author Date Id Revision