Thuban/Model/layer.py

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

__version__ = "$Revision$"

from math import log, ceil

import shapelib, shptree

from messages import LAYER_PROJECTION_CHANGED, LAYER_LEGEND_CHANGED, \
     LAYER_VISIBILITY_CHANGED

from color import Color
# Some predefined colors for internal use
_black = Color(0, 0, 0)


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 = None, stroke = _black, stroke_width = 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 None if the shapes are not filled
        stroke -- the stroke color or 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)
        self.filename = filename
        self.projection = projection
        self.fill = fill
        self.stroke = stroke
        self.stroke_width = stroke_width
        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

    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]
            self.bbox = mins[:2] + maxs[:2]

            # 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 BoundingBox(self):
        """Return the bounding box of the layer's shapes in their default
        coordinate system"""
        self.open_shapefile()
        return self.bbox

    def LatLongBoundingBox(self):
        """Return the layer's bounding box in lat/long coordinates"""
        llx, lly, urx, ury = self.BoundingBox()
        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

    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 SetFill(self, fill):
        """Set the layer's fill color. None means the shapes are not filled"""
        self.fill = fill
        self.changed(LAYER_LEGEND_CHANGED, self)

    def SetStroke(self, stroke):
        """Set the layer's stroke color. None means the shapes are not
        stroked."""
        self.stroke = stroke
        self.changed(LAYER_LEGEND_CHANGED, self)

    def SetStrokeWidth(self, width):
        """Set the layer's stroke width."""
        self.stroke_width = width
        self.changed(LAYER_LEGEND_CHANGED, self)
1	# Copyright (c) 2001, 2002 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 Thuban for details.
7
8	__version__ = "$Revision$"
9
10	from math import log, ceil
11
12	import shapelib, shptree
13
14	from messages import LAYER_PROJECTION_CHANGED, LAYER_LEGEND_CHANGED, \
15	LAYER_VISIBILITY_CHANGED
16
17	from color import Color
18	# Some predefined colors for internal use
19	_black = Color(0, 0, 0)
20
21
22	from table import Table
23
24	from base import TitledObject, Modifiable
25
26	class Shape:
27
28	"""Represent one shape"""
29
30	def __init__(self, points):
31	self.points = points
32	#self.compute_bbox()
33
34	def compute_bbox(self):
35	xs = []
36	ys = []
37	for x, y in self.points:
38	xs.append(x)
39	ys.append(y)
40	self.llx = min(xs)
41	self.lly = min(ys)
42	self.urx = max(xs)
43	self.ury = max(ys)
44
45	def Points(self):
46	return self.points
47
48
49
50	# Shape type constants
51	SHAPETYPE_POLYGON = "polygon"
52	SHAPETYPE_ARC = "arc"
53	SHAPETYPE_POINT = "point"
54
55	# mapping from shapelib shapetype constants to our constants
56	shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
57	shapelib.SHPT_ARC: SHAPETYPE_ARC,
58	shapelib.SHPT_POINT: SHAPETYPE_POINT}
59
60	shapetype_names = {SHAPETYPE_POINT: "Point",
61	SHAPETYPE_ARC: "Arc",
62	SHAPETYPE_POLYGON: "Polygon"}
63
64	class BaseLayer(TitledObject, Modifiable):
65
66	"""Base class for the layers."""
67
68	def __init__(self, title, visible = 1):
69	"""Initialize the layer.
70
71	title -- the title
72	visible -- boolean. If true the layer is visible.
73	"""
74	TitledObject.__init__(self, title)
75	Modifiable.__init__(self)
76	self.visible = visible
77
78	def Visible(self):
79	"""Return true if layer is visible"""
80	return self.visible
81
82	def SetVisible(self, visible):
83	"""Set the layer's visibility."""
84	self.visible = visible
85	self.issue(LAYER_VISIBILITY_CHANGED, self)
86
87
88	class Layer(BaseLayer):
89
90	"""Represent the information of one geodata file (currently a shapefile)
91
92	All children of the layer have the same type.
93
94	A layer has fill and stroke colors. Colors should be instances of
95	Color. They can also be None, indicating no fill or no stroke.
96
97	The layer objects send the following events, all of which have the
98	layer object as parameter:
99
100	TITLE_CHANGED -- The title has changed.
101	LAYER_PROJECTION_CHANGED -- the projection has changed.
102	LAYER_LEGEND_CHANGED -- the fill or stroke attributes have changed
103
104	"""
105
106	def __init__(self, title, filename, projection = None,
107	fill = None, stroke = _black, stroke_width = 1, visible = 1):
108	"""Initialize the layer.
109
110	title -- the title
111	filename -- the name of the shapefile
112	projection -- the projection object. Its Inverse method is
113	assumed to map the layer's coordinates to lat/long
114	coordinates
115	fill -- the fill color or None if the shapes are not filled
116	stroke -- the stroke color or None if the shapes are not stroked
117	visible -- boolean. If true the layer is visible.
118
119	colors are expected to be instances of Color class
120	"""
121	BaseLayer.__init__(self, title, visible = visible)
122	self.filename = filename
123	self.projection = projection
124	self.fill = fill
125	self.stroke = stroke
126	self.stroke_width = stroke_width
127	self.shapefile = None
128	self.shapetree = None
129	self.open_shapefile()
130	# shapetable is the table associated with the shapefile, while
131	# table is the default table used to look up attributes for
132	# display
133	self.shapetable = Table(filename)
134	self.table = self.shapetable
135
136	def open_shapefile(self):
137	if self.shapefile is None:
138	self.shapefile = shapelib.ShapeFile(self.filename)
139	numshapes, shapetype, mins, maxs = self.shapefile.info()
140	self.numshapes = numshapes
141	self.shapetype = shapelib_shapetypes[shapetype]
142	self.bbox = mins[:2] + maxs[:2]
143
144	# estimate a good depth for the quad tree. Each depth
145	# multiplies the number of nodes by four, therefore we
146	# basically take the base 4 logarithm of the number of
147	# shapes.
148	if self.numshapes < 4:
149	maxdepth = 1
150	else:
151	maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
152
153	self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
154	maxdepth)
155
156	def BoundingBox(self):
157	"""Return the bounding box of the layer's shapes in their default
158	coordinate system"""
159	self.open_shapefile()
160	return self.bbox
161
162	def LatLongBoundingBox(self):
163	"""Return the layer's bounding box in lat/long coordinates"""
164	llx, lly, urx, ury = self.BoundingBox()
165	if self.projection is not None:
166	llx, lly = self.projection.Inverse(llx, lly)
167	urx, ury = self.projection.Inverse(urx, ury)
168	return llx, lly, urx, ury
169
170	def NumShapes(self):
171	"""Return the number of shapes in the layer"""
172	self.open_shapefile()
173	return self.numshapes
174
175	def ShapeType(self):
176	"""Return the type of the shapes in the layer.
177	This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
178	"""
179	self.open_shapefile()
180	return self.shapetype
181
182	def Shape(self, index):
183	"""Return the shape with index index"""
184	self.open_shapefile()
185	shape = self.shapefile.read_object(index)
186	if self.shapetype == SHAPETYPE_POINT:
187	points = shape.vertices()
188	else:
189	#for poly in shape.vertices():
190	poly = shape.vertices()[0]
191	points = []
192	for x, y in poly:
193	points.append((x, y))
194	return Shape(points)
195
196	def ShapesInRegion(self, box):
197	"""Return the ids of the shapes that overlap the box.
198
199	Box is a tuple (left, bottom, right, top) in the coordinate
200	system used by the layer's shapefile.
201	"""
202	left, bottom, right, top = box
203	return self.shapetree.find_shapes((left, bottom), (right, top))
204
205	def SetProjection(self, projection):
206	"""Set the layer's projection"""
207	self.projection = projection
208	self.changed(LAYER_PROJECTION_CHANGED, self)
209
210	def SetFill(self, fill):
211	"""Set the layer's fill color. None means the shapes are not filled"""
212	self.fill = fill
213	self.changed(LAYER_LEGEND_CHANGED, self)
214
215	def SetStroke(self, stroke):
216	"""Set the layer's stroke color. None means the shapes are not
217	stroked."""
218	self.stroke = stroke
219	self.changed(LAYER_LEGEND_CHANGED, self)
220
221	def SetStrokeWidth(self, width):
222	"""Set the layer's stroke width."""
223	self.stroke_width = width
224	self.changed(LAYER_LEGEND_CHANGED, self)
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision