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]

            # 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 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 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	bh	73	# Copyright (c) 2001, 2002 by Intevation GmbH
2	bh	6	# 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	bh	171	from math import log, ceil
11
12	bh	143	import shapelib, shptree
13	bh	6
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	bh	73	fill = None, stroke = _black, stroke_width = 1, visible = 1):
108	bh	6	"""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	bh	73	self.stroke_width = stroke_width
127	bh	6	self.shapefile = None
128	bh	143	self.shapetree = None
129	bh	21	self.open_shapefile()
130	bh	6	# 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
143	bh	179	# if there are shapes, set the bbox accordinly. Otherwise
144			# set it to None.
145			if self.numshapes:
146			self.bbox = mins[:2] + maxs[:2]
147			else:
148			self.bbox = None
149
150	bh	171	# estimate a good depth for the quad tree. Each depth
151			# multiplies the number of nodes by four, therefore we
152			# basically take the base 4 logarithm of the number of
153			# shapes.
154			if self.numshapes < 4:
155			maxdepth = 1
156			else:
157			maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
158
159			self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
160			maxdepth)
161
162	bh	6	def BoundingBox(self):
163	bh	179	"""Return the layer's bounding box in the intrinsic coordinate system.
164
165			If the layer has no shapes, return None.
166			"""
167			# The bbox will be set by open_shapefile just as we need it
168			# here.
169	bh	6	self.open_shapefile()
170			return self.bbox
171
172			def LatLongBoundingBox(self):
173	bh	179	"""Return the layer's bounding box in lat/long coordinates.
174	bh	6
175	bh	179	Return None, if the layer doesn't contain any shapes.
176			"""
177			bbox = self.BoundingBox()
178			if bbox is not None:
179			llx, lly, urx, ury = bbox
180			if self.projection is not None:
181			llx, lly = self.projection.Inverse(llx, lly)
182			urx, ury = self.projection.Inverse(urx, ury)
183			return llx, lly, urx, ury
184			else:
185			return None
186
187	bh	6	def NumShapes(self):
188			"""Return the number of shapes in the layer"""
189			self.open_shapefile()
190			return self.numshapes
191
192			def ShapeType(self):
193			"""Return the type of the shapes in the layer.
194			This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
195			"""
196			self.open_shapefile()
197			return self.shapetype
198
199			def Shape(self, index):
200			"""Return the shape with index index"""
201			self.open_shapefile()
202			shape = self.shapefile.read_object(index)
203			if self.shapetype == SHAPETYPE_POINT:
204			points = shape.vertices()
205			else:
206			#for poly in shape.vertices():
207			poly = shape.vertices()[0]
208			points = []
209			for x, y in poly:
210	bh	82	points.append((x, y))
211	bh	6	return Shape(points)
212
213	bh	143	def ShapesInRegion(self, box):
214			"""Return the ids of the shapes that overlap the box.
215
216			Box is a tuple (left, bottom, right, top) in the coordinate
217			system used by the layer's shapefile.
218			"""
219			left, bottom, right, top = box
220	bh	147	return self.shapetree.find_shapes((left, bottom), (right, top))
221	bh	143
222	bh	6	def SetProjection(self, projection):
223			"""Set the layer's projection"""
224			self.projection = projection
225			self.changed(LAYER_PROJECTION_CHANGED, self)
226
227			def SetFill(self, fill):
228			"""Set the layer's fill color. None means the shapes are not filled"""
229			self.fill = fill
230			self.changed(LAYER_LEGEND_CHANGED, self)
231
232			def SetStroke(self, stroke):
233			"""Set the layer's stroke color. None means the shapes are not
234			stroked."""
235			self.stroke = stroke
236			self.changed(LAYER_LEGEND_CHANGED, self)
237	bh	73
238			def SetStrokeWidth(self, width):
239			"""Set the layer's stroke width."""
240			self.stroke_width = width
241			self.changed(LAYER_LEGEND_CHANGED, self)
Name	Value
svn:eol-style	native
svn:keywords	Author Date Id Revision