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.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.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
        """

        if clazz is None:
            self.__classification = classification.Classification()
        else:
 
            # prevent infinite recursion when calling SetLayer()
            if clazz == self.__classification:
                return

            self.__classification = clazz
            self.__classification.SetLayer(self)

        self.changed(LAYER_LEGEND_CHANGED, self)

    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
151
152	self.SetClassification(None)
153
154	self.__classification.SetDefaultLineColor(stroke)
155	self.__classification.SetDefaultLineWidth(lineWidth)
156	self.__classification.SetDefaultFill(fill)
157	self.__classification.SetLayer(self)
158
159	self.UnsetModified()
160
161	def open_shapefile(self):
162	if self.shapefile is None:
163	self.shapefile = shapelib.ShapeFile(self.filename)
164	numshapes, shapetype, mins, maxs = self.shapefile.info()
165	self.numshapes = numshapes
166	self.shapetype = shapelib_shapetypes[shapetype]
167
168	# if there are shapes, set the bbox accordinly. Otherwise
169	# set it to None.
170	if self.numshapes:
171	self.bbox = mins[:2] + maxs[:2]
172	else:
173	self.bbox = None
174
175	# estimate a good depth for the quad tree. Each depth
176	# multiplies the number of nodes by four, therefore we
177	# basically take the base 4 logarithm of the number of
178	# shapes.
179	if self.numshapes < 4:
180	maxdepth = 1
181	else:
182	maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
183
184	self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
185	maxdepth)
186
187	def Destroy(self):
188	BaseLayer.Destroy(self)
189	if self.shapefile is not None:
190	self.shapefile.close()
191	self.shapefile = None
192	self.shapetree = None
193	self.table.Destroy()
194
195	def BoundingBox(self):
196	"""Return the layer's bounding box in the intrinsic coordinate system.
197
198	If the layer has no shapes, return None.
199	"""
200	# The bbox will be set by open_shapefile just as we need it
201	# here.
202	self.open_shapefile()
203	return self.bbox
204
205	def LatLongBoundingBox(self):
206	"""Return the layer's bounding box in lat/long coordinates.
207
208	Return None, if the layer doesn't contain any shapes.
209	"""
210	bbox = self.BoundingBox()
211	if bbox is not None:
212	llx, lly, urx, ury = bbox
213	if self.projection is not None:
214	llx, lly = self.projection.Inverse(llx, lly)
215	urx, ury = self.projection.Inverse(urx, ury)
216	return llx, lly, urx, ury
217	else:
218	return None
219
220	def GetFieldType(self, fieldName):
221	self.open_shapefile()
222	info = self.table.field_info_by_name(fieldName)
223	if info is not None:
224	return info[0]
225	else:
226	return None
227
228	def NumShapes(self):
229	"""Return the number of shapes in the layer"""
230	self.open_shapefile()
231	return self.numshapes
232
233	def ShapeType(self):
234	"""Return the type of the shapes in the layer.
235	This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
236	"""
237	self.open_shapefile()
238	return self.shapetype
239
240	def Shape(self, index):
241	"""Return the shape with index index"""
242	self.open_shapefile()
243	shape = self.shapefile.read_object(index)
244
245	if self.shapetype == SHAPETYPE_POINT:
246	points = shape.vertices()
247	else:
248	#for poly in shape.vertices():
249	poly = shape.vertices()[0]
250	points = []
251	for x, y in poly:
252	points.append((x, y))
253
254	return Shape(points)
255
256	def ShapesInRegion(self, box):
257	"""Return the ids of the shapes that overlap the box.
258
259	Box is a tuple (left, bottom, right, top) in the coordinate
260	system used by the layer's shapefile.
261	"""
262	left, bottom, right, top = box
263	return self.shapetree.find_shapes((left, bottom), (right, top))
264
265	def SetProjection(self, projection):
266	"""Set the layer's projection"""
267	self.projection = projection
268	self.changed(LAYER_PROJECTION_CHANGED, self)
269
270	def GetClassification(self):
271	return self.__classification
272
273	def SetClassification(self, clazz):
274	"""Set the classification to 'clazz'
275
276	If 'clazz' is None a default classification is created
277	"""
278
279	if clazz is None:
280	self.__classification = classification.Classification()
281	else:
282
283	# prevent infinite recursion when calling SetLayer()
284	if clazz == self.__classification:
285	return
286
287	self.__classification = clazz
288	self.__classification.SetLayer(self)
289
290	self.changed(LAYER_LEGEND_CHANGED, self)
291
292	def ClassChanged(self):
293	"""Called from the classification object when it has changed."""
294	self.changed(LAYER_LEGEND_CHANGED, self)
295
296	def TreeInfo(self):
297	items = []
298
299	if self.Visible():
300	items.append(_("Shown"))
301	else:
302	items.append(_("Hidden"))
303	items.append(_("Shapes: %d") % self.NumShapes())
304
305	bbox = self.LatLongBoundingBox()
306	if bbox is not None:
307	items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
308	else:
309	items.append(_("Extent (lat-lon):"))
310	items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()])
311
312	items.append(self.__classification)
313
314	return (_("Layer '%s'") % self.Title(), items)
315
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svn:keywords	Author Date Id Revision