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(classification.Classification(self))
        self.__classification.SetDefaultLineColor(stroke)
        self.__classification.SetDefaultLineWidth(lineWidth)
        self.__classification.SetDefaultFill(fill)

        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):

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