Thuban/Model/layer.py

# Copyright (c) 2001, 2002 by Intevation GmbH
# Authors:
# Bernhard Herzog <[email protected]>
# Jonathan Coles <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with Thuban for details.

__version__ = "$Revision$"

import os
from math import log, ceil

from Thuban import _

import shapelib, shptree

from messages import LAYER_PROJECTION_CHANGED, LAYER_LEGEND_CHANGED, \
     LAYER_VISIBILITY_CHANGED

from color import Color

import classification

from table import Table

from base import TitledObject, Modifiable

class Shape:

    """Represent one shape"""

    def __init__(self, points):
        self.points = points
        #self.compute_bbox()

    def compute_bbox(self):
        xs = []
        ys = []
        for x, y in self.points:
            xs.append(x)
            ys.append(y)
        self.llx = min(xs)
        self.lly = min(ys)
        self.urx = max(xs)
        self.ury = max(ys)

    def Points(self):
        return self.points


# 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}

shapetype_names = {SHAPETYPE_POINT: "Point",
                   SHAPETYPE_ARC: "Arc",
                   SHAPETYPE_POLYGON: "Polygon"}

class BaseLayer(TitledObject, Modifiable):

    """Base class for the layers."""

    def __init__(self, title, visible = 1):
        """Initialize the layer.

        title -- the title
        visible -- boolean. If true the layer is visible.
        """
        TitledObject.__init__(self, title)
        Modifiable.__init__(self)
        self.visible = visible

    def Visible(self):
        """Return true if layer is visible"""
        return self.visible

    def SetVisible(self, visible):
        """Set the layer's visibility."""
        self.visible = visible
        self.issue(LAYER_VISIBILITY_CHANGED, self)


class Layer(BaseLayer):

    """Represent the information of one geodata file (currently a shapefile)

    All children of the layer have the same type.

    A layer has fill and stroke colors. Colors should be instances of
    Color. They can also be None, indicating no fill or no stroke.

    The layer objects send the following events, all of which have the
    layer object as parameter:

        TITLE_CHANGED -- The title has changed.
        LAYER_PROJECTION_CHANGED -- the projection has changed.
        LAYER_LEGEND_CHANGED -- the fill or stroke attributes have changed

    """

    def __init__(self, title, filename, projection = None,
                 fill = Color.None, 
                 stroke = Color.Black, 
                 lineWidth = 1, 
                 visible = 1):
        """Initialize the layer.

        title -- the title
        filename -- the name of the shapefile
        projection -- the projection object. Its Inverse method is
               assumed to map the layer's coordinates to lat/long
               coordinates
        fill -- the fill color or Color.None if the shapes are not filled
        stroke -- the stroke color or Color.None if the shapes are not stroked
        visible -- boolean. If true the layer is visible.

        colors are expected to be instances of Color class
        """
        BaseLayer.__init__(self, title, visible = visible)

        # 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.projection = projection
        self.shapefile = None
        self.shapetree = None
        self.open_shapefile()
        # shapetable is the table associated with the shapefile, while
        # table is the default table used to look up attributes for
        # display
        self.shapetable = Table(filename)
        self.table = self.shapetable

        #
        # this is really important so that when the classification class
        # tries to set its parent layer the variable will exist
        #
        self.__classification = None 
        self.__setClassLock = False


        self.SetClassification(None)

        self.__classification.SetDefaultLineColor(stroke)
        self.__classification.SetDefaultLineWidth(lineWidth)
        self.__classification.SetDefaultFill(fill)
        self.__classification.SetLayer(self)

        self.UnsetModified()

    def open_shapefile(self):
        if self.shapefile is None:
            self.shapefile = shapelib.ShapeFile(self.filename)
            numshapes, shapetype, mins, maxs = self.shapefile.info()
            self.numshapes = numshapes
            self.shapetype = shapelib_shapetypes[shapetype]

            # if there are shapes, set the bbox accordinly. Otherwise
            # set it to None.
            if self.numshapes:
                self.bbox = mins[:2] + maxs[:2]
            else:
                self.bbox = None

            # 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 Destroy(self):
        BaseLayer.Destroy(self)
        if self.shapefile is not None:
            self.shapefile.close()
            self.shapefile = None
            self.shapetree = None
        self.SetClassification(None)
        self.table.Destroy()

    def BoundingBox(self):
        """Return the layer's bounding box in the intrinsic coordinate system.

        If the layer has no shapes, return None.
        """
        # The bbox will be set by open_shapefile just as we need it
        # here.
        self.open_shapefile()
        return self.bbox

    def LatLongBoundingBox(self):
        """Return the layer's bounding box in lat/long coordinates.

        Return None, if the layer doesn't contain any shapes.
        """
        bbox = self.BoundingBox()
        if bbox is not None:
            llx, lly, urx, ury = bbox
            if self.projection is not None:
                llx, lly = self.projection.Inverse(llx, lly)
                urx, ury = self.projection.Inverse(urx, ury)
            return llx, lly, urx, ury
        else:
            return None

    def GetFieldType(self, fieldName):
        self.open_shapefile()
        info = self.table.field_info_by_name(fieldName)
        if info is not None:
            return info[0]
        else:
            return None

    def NumShapes(self):
        """Return the number of shapes in the layer"""
        self.open_shapefile()
        return self.numshapes

    def ShapeType(self):
        """Return the type of the shapes in the layer.
        This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
        """
        self.open_shapefile()
        return self.shapetype

    def Shape(self, index):
        """Return the shape with index index"""
        self.open_shapefile()
        shape = self.shapefile.read_object(index)

        if self.shapetype == SHAPETYPE_POINT:
            points = shape.vertices()
        else:
            #for poly in shape.vertices():
            poly = shape.vertices()[0]
            points = []
            for x, y in poly:
                points.append((x, y))

        return Shape(points)

    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 by the layer's shapefile.
        """
        left, bottom, right, top = box
        return self.shapetree.find_shapes((left, bottom), (right, top))

    def SetProjection(self, projection):
        """Set the layer's projection"""
        self.projection = projection
        self.changed(LAYER_PROJECTION_CHANGED, self)

    def GetClassification(self):
        return self.__classification

    def SetClassification(self, clazz):
        """Set the classification to 'clazz'

        If 'clazz' is None a default classification is created
        """

        # prevent infinite recursion when calling SetLayer()
        if self.__setClassLock: return

        self.__setClassLock = True

        if clazz is None:
            if self.__classification is not None:
                self.__classification.SetLayer(None)
            self.__classification = classification.Classification()
        else:
            self.__classification = clazz
            try:
                self.__classification.SetLayer(self)
            except ValueError:
                self.__setClassLock = False
                raise ValueError

        self.changed(LAYER_LEGEND_CHANGED, self)

        self.__setClassLock = False

    def ClassChanged(self):
        """Called from the classification object when it has changed."""
        self.changed(LAYER_LEGEND_CHANGED, self)
 
    def TreeInfo(self):
        items = []

        if self.Visible():
            items.append(_("Shown"))
        else:
            items.append(_("Hidden"))
        items.append(_("Shapes: %d") % self.NumShapes())

        bbox = self.LatLongBoundingBox()
        if bbox is not None:
            items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
        else:
            items.append(_("Extent (lat-lon):"))
        items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()])

        items.append(self.__classification)

        return (_("Layer '%s'") % self.Title(), items)

1	# Copyright (c) 2001, 2002 by Intevation GmbH
2	# Authors:
3	# Bernhard Herzog <[email protected]>
4	# Jonathan Coles <[email protected]>
5	#
6	# This program is free software under the GPL (>=v2)
7	# Read the file COPYING coming with Thuban for details.
8
9	__version__ = "$Revision$"
10
11	import os
12	from math import log, ceil
13
14	from Thuban import _
15
16	import shapelib, shptree
17
18	from messages import LAYER_PROJECTION_CHANGED, LAYER_LEGEND_CHANGED, \
19	LAYER_VISIBILITY_CHANGED
20
21	from color import Color
22
23	import classification
24
25	from table import Table
26
27	from base import TitledObject, Modifiable
28
29	class Shape:
30
31	"""Represent one shape"""
32
33	def __init__(self, points):
34	self.points = points
35	#self.compute_bbox()
36
37	def compute_bbox(self):
38	xs = []
39	ys = []
40	for x, y in self.points:
41	xs.append(x)
42	ys.append(y)
43	self.llx = min(xs)
44	self.lly = min(ys)
45	self.urx = max(xs)
46	self.ury = max(ys)
47
48	def Points(self):
49	return self.points
50
51
52
53	# Shape type constants
54	SHAPETYPE_POLYGON = "polygon"
55	SHAPETYPE_ARC = "arc"
56	SHAPETYPE_POINT = "point"
57
58	# mapping from shapelib shapetype constants to our constants
59	shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
60	shapelib.SHPT_ARC: SHAPETYPE_ARC,
61	shapelib.SHPT_POINT: SHAPETYPE_POINT}
62
63	shapetype_names = {SHAPETYPE_POINT: "Point",
64	SHAPETYPE_ARC: "Arc",
65	SHAPETYPE_POLYGON: "Polygon"}
66
67	class BaseLayer(TitledObject, Modifiable):
68
69	"""Base class for the layers."""
70
71	def __init__(self, title, visible = 1):
72	"""Initialize the layer.
73
74	title -- the title
75	visible -- boolean. If true the layer is visible.
76	"""
77	TitledObject.__init__(self, title)
78	Modifiable.__init__(self)
79	self.visible = visible
80
81	def Visible(self):
82	"""Return true if layer is visible"""
83	return self.visible
84
85	def SetVisible(self, visible):
86	"""Set the layer's visibility."""
87	self.visible = visible
88	self.issue(LAYER_VISIBILITY_CHANGED, self)
89
90
91	class Layer(BaseLayer):
92
93	"""Represent the information of one geodata file (currently a shapefile)
94
95	All children of the layer have the same type.
96
97	A layer has fill and stroke colors. Colors should be instances of
98	Color. They can also be None, indicating no fill or no stroke.
99
100	The layer objects send the following events, all of which have the
101	layer object as parameter:
102
103	TITLE_CHANGED -- The title has changed.
104	LAYER_PROJECTION_CHANGED -- the projection has changed.
105	LAYER_LEGEND_CHANGED -- the fill or stroke attributes have changed
106
107	"""
108
109	def __init__(self, title, filename, projection = None,
110	fill = Color.None,
111	stroke = Color.Black,
112	lineWidth = 1,
113	visible = 1):
114	"""Initialize the layer.
115
116	title -- the title
117	filename -- the name of the shapefile
118	projection -- the projection object. Its Inverse method is
119	assumed to map the layer's coordinates to lat/long
120	coordinates
121	fill -- the fill color or Color.None if the shapes are not filled
122	stroke -- the stroke color or Color.None if the shapes are not stroked
123	visible -- boolean. If true the layer is visible.
124
125	colors are expected to be instances of Color class
126	"""
127	BaseLayer.__init__(self, title, visible = visible)
128
129	# Make the filename absolute. The filename will be
130	# interpreted relative to that anyway, but when saving a
131	# session we need to compare absolute paths and it's usually
132	# safer to always work with absolute paths.
133	self.filename = os.path.abspath(filename)
134
135	self.projection = projection
136	self.shapefile = None
137	self.shapetree = None
138	self.open_shapefile()
139	# shapetable is the table associated with the shapefile, while
140	# table is the default table used to look up attributes for
141	# display
142	self.shapetable = Table(filename)
143	self.table = self.shapetable
144
145	#
146	# this is really important so that when the classification class
147	# tries to set its parent layer the variable will exist
148	#
149	self.__classification = None
150	self.__setClassLock = False
151
152
153	self.SetClassification(None)
154
155	self.__classification.SetDefaultLineColor(stroke)
156	self.__classification.SetDefaultLineWidth(lineWidth)
157	self.__classification.SetDefaultFill(fill)
158	self.__classification.SetLayer(self)
159
160	self.UnsetModified()
161
162	def open_shapefile(self):
163	if self.shapefile is None:
164	self.shapefile = shapelib.ShapeFile(self.filename)
165	numshapes, shapetype, mins, maxs = self.shapefile.info()
166	self.numshapes = numshapes
167	self.shapetype = shapelib_shapetypes[shapetype]
168
169	# if there are shapes, set the bbox accordinly. Otherwise
170	# set it to None.
171	if self.numshapes:
172	self.bbox = mins[:2] + maxs[:2]
173	else:
174	self.bbox = None
175
176	# estimate a good depth for the quad tree. Each depth
177	# multiplies the number of nodes by four, therefore we
178	# basically take the base 4 logarithm of the number of
179	# shapes.
180	if self.numshapes < 4:
181	maxdepth = 1
182	else:
183	maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
184
185	self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
186	maxdepth)
187
188	def Destroy(self):
189	BaseLayer.Destroy(self)
190	if self.shapefile is not None:
191	self.shapefile.close()
192	self.shapefile = None
193	self.shapetree = None
194	self.SetClassification(None)
195	self.table.Destroy()
196
197	def BoundingBox(self):
198	"""Return the layer's bounding box in the intrinsic coordinate system.
199
200	If the layer has no shapes, return None.
201	"""
202	# The bbox will be set by open_shapefile just as we need it
203	# here.
204	self.open_shapefile()
205	return self.bbox
206
207	def LatLongBoundingBox(self):
208	"""Return the layer's bounding box in lat/long coordinates.
209
210	Return None, if the layer doesn't contain any shapes.
211	"""
212	bbox = self.BoundingBox()
213	if bbox is not None:
214	llx, lly, urx, ury = bbox
215	if self.projection is not None:
216	llx, lly = self.projection.Inverse(llx, lly)
217	urx, ury = self.projection.Inverse(urx, ury)
218	return llx, lly, urx, ury
219	else:
220	return None
221
222	def GetFieldType(self, fieldName):
223	self.open_shapefile()
224	info = self.table.field_info_by_name(fieldName)
225	if info is not None:
226	return info[0]
227	else:
228	return None
229
230	def NumShapes(self):
231	"""Return the number of shapes in the layer"""
232	self.open_shapefile()
233	return self.numshapes
234
235	def ShapeType(self):
236	"""Return the type of the shapes in the layer.
237	This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
238	"""
239	self.open_shapefile()
240	return self.shapetype
241
242	def Shape(self, index):
243	"""Return the shape with index index"""
244	self.open_shapefile()
245	shape = self.shapefile.read_object(index)
246
247	if self.shapetype == SHAPETYPE_POINT:
248	points = shape.vertices()
249	else:
250	#for poly in shape.vertices():
251	poly = shape.vertices()[0]
252	points = []
253	for x, y in poly:
254	points.append((x, y))
255
256	return Shape(points)
257
258	def ShapesInRegion(self, box):
259	"""Return the ids of the shapes that overlap the box.
260
261	Box is a tuple (left, bottom, right, top) in the coordinate
262	system used by the layer's shapefile.
263	"""
264	left, bottom, right, top = box
265	return self.shapetree.find_shapes((left, bottom), (right, top))
266
267	def SetProjection(self, projection):
268	"""Set the layer's projection"""
269	self.projection = projection
270	self.changed(LAYER_PROJECTION_CHANGED, self)
271
272	def GetClassification(self):
273	return self.__classification
274
275	def SetClassification(self, clazz):
276	"""Set the classification to 'clazz'
277
278	If 'clazz' is None a default classification is created
279	"""
280
281	# prevent infinite recursion when calling SetLayer()
282	if self.__setClassLock: return
283
284	self.__setClassLock = True
285
286	if clazz is None:
287	if self.__classification is not None:
288	self.__classification.SetLayer(None)
289	self.__classification = classification.Classification()
290	else:
291	self.__classification = clazz
292	try:
293	self.__classification.SetLayer(self)
294	except ValueError:
295	self.__setClassLock = False
296	raise ValueError
297
298	self.changed(LAYER_LEGEND_CHANGED, self)
299
300	self.__setClassLock = False
301
302	def ClassChanged(self):
303	"""Called from the classification object when it has changed."""
304	self.changed(LAYER_LEGEND_CHANGED, self)
305
306	def TreeInfo(self):
307	items = []
308
309	if self.Visible():
310	items.append(_("Shown"))
311	else:
312	items.append(_("Hidden"))
313	items.append(_("Shapes: %d") % self.NumShapes())
314
315	bbox = self.LatLongBoundingBox()
316	if bbox is not None:
317	items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
318	else:
319	items.append(_("Extent (lat-lon):"))
320	items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()])
321
322	items.append(self.__classification)
323
324	return (_("Layer '%s'") % self.Title(), items)
325
Name	Value
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svn:keywords	Author Date Id Revision