Thuban/Model/layer.py

# Copyright (c) 2001, 2002, 2003 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__ = "$Revision$"

from math import log, ceil

from Thuban import _

import shapelib, shptree

import gdal
from gdalconst import GA_ReadOnly

from messages import LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED, \
     LAYER_CHANGED

from color import Color

import classification

from base import TitledObject, Modifiable


class Shape:

    """Represent one shape"""

    def __init__(self, points):
        self.points = points
        #self.compute_bbox()
        self.bbox = None

    def compute_bbox(self):
        if self.bbox is not None:
            return self.bbox

        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)

        self.bbox = (self.llx, self.lly, self.urx, self.ury)

        return self.bbox

    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 = True, projection = None):
        """Initialize the layer.

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

    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)

    def HasClassification(self):
        """Determine if this layer support classifications."""
        return False

    def GetProjection(self):
        """Return the layer's projection."""
        return self.projection

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

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

        title -- the title
        data -- datastore object for the shape data shown by the layer
        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.Transparent if the shapes are 
                not filled
        stroke -- the stroke color or Color.Transparent 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,
                                 projection = projection)

        #
        # 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.SetShapeStore(data)

        self.SetClassification(None)

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

        self.UnsetModified()


    def SetShapeStore(self, store):
        self.store = store
        self.shapefile = self.store.Shapefile()
        self.shapetable = self.store.Table()
        self.filename = self.store.filename
        self.table = self.shapetable

        numshapes, shapetype, mins, maxs = self.shapefile.info()
        self.numshapes = numshapes
        self.shapetype = shapelib_shapetypes[shapetype]

        # if there are shapes, set the bbox accordingly. 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)
        if self.__classification is not None:
            fieldname = self.__classification.GetField()
            if fieldname is not None and \
               not self.store.Table().HasColumn(fieldname):
                self.SetClassification(None)
        self.changed(LAYER_CHANGED, self)

    def ShapeStore(self):
        return self.store

    def Destroy(self):
        BaseLayer.Destroy(self)
        self.SetClassification(None)

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

        If the layer has no shapes, return None.
        """
        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 ShapesBoundingBox(self, shapes):
        """Return a bounding box in lat/long coordinates for the given
        list of shape ids.

        If shapes is None or empty, return None.
        """

        if shapes is None or len(shapes) == 0: return None

        llx = []
        lly = []
        urx = []
        ury = []

        if self.projection is not None:
            inverse = lambda x, y: self.projection.Inverse(x, y)
        else:
            inverse = lambda x, y: (x, y)

        for id in shapes:
            left, bottom, right, top = self.Shape(id).compute_bbox()

            left, bottom = inverse(left, bottom)
            right, top   = inverse(right, top)

            llx.append(left)
            lly.append(bottom)
            urx.append(right)
            ury.append(top)

        return (min(llx), min(lly), max(urx), max(ury))

    def GetFieldType(self, fieldName):
        if self.table.HasColumn(fieldName):
            return self.table.Column(fieldName).type
        return None

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

    def Shape(self, index):
        """Return the shape with index index"""
        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 unprojected coordinates.
        """
        left, bottom, right, top = box

        if self.projection is not None:
            left,  bottom = self.projection.Forward(left, bottom)
            right, top    = self.projection.Forward(right, top)

        return self.shapetree.find_shapes((left, bottom), (right, top))

    def HasClassification(self):
        return True

    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_CHANGED, self)

        self.__setClassLock = False

    def ClassChanged(self):
        """Called from the classification object when it has changed."""
        self.changed(LAYER_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()])

        if self.projection and len(self.projection.params) > 0:
            items.append((_("Projection"),
                        [str(param) for param in self.projection.params]))

        items.append(self.__classification)

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


class RasterLayer(BaseLayer):

    def __init__(self, title, filename, projection = None, visible = True):
        """Initialize the Raster Layer.

        title -- title for the layer.

        filename -- file name of the source image.

        projection -- Projection object describing the projection which
                      the source image is in.

        visible -- True is the layer should initially be visible.

        Throws IOError if the filename is invalid or points to a file that
        is not in a format GDAL can use.
        """

        BaseLayer.__init__(self, title, visible = visible)

        self.projection = projection
        self.filename = filename

        self.bbox = -1

        #
        # temporarily open the file so that GDAL can test if it's valid.
        #
        dataset = gdal.Open(self.filename, GA_ReadOnly)

        if dataset is None:
            raise IOError()

        self.UnsetModified()

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

        If the layer has no shapes, return None.
        """
        if self.bbox == -1:
            dataset = gdal.Open(self.filename, GA_ReadOnly)
            if dataset is None:
                self.bbox = None
            else:
                geotransform = dataset.GetGeoTransform()
                if geotransform is None:
                    return None

                x = 0
                y = dataset.RasterYSize
                left = geotransform[0] +        \
                       geotransform[1] * x +    \
                       geotransform[2] * y

                bottom = geotransform[3] +      \
                         geotransform[4] * x +  \
                         geotransform[5] * y

                x = dataset.RasterXSize
                y = 0
                right = geotransform[0] +       \
                        geotransform[1] * x +   \
                        geotransform[2] * y

                top = geotransform[3] +         \
                      geotransform[4] * x +     \
                      geotransform[5] * y

                self.bbox = (left, bottom, right, top)

        return self.bbox

    def LatLongBoundingBox(self):
        bbox = self.BoundingBox()
        if bbox is None:
            return 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

    def GetImageFilename(self):
        return self.filename

    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):"))

        if self.projection and len(self.projection.params) > 0:
            items.append((_("Projection"),
                        [str(param) for param in self.projection.params]))

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

1	bh	701	# Copyright (c) 2001, 2002, 2003 by Intevation GmbH
2	bh	6	# Authors:
3			# Bernhard Herzog <[email protected]>
4	jonathan	412	# Jonathan Coles <[email protected]>
5	bh	6	#
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	bh	171	from math import log, ceil
12
13	jan	374	from Thuban import _
14
15	bh	143	import shapelib, shptree
16	bh	6
17	jonathan	929	import gdal
18			from gdalconst import GA_ReadOnly
19
20	bh	701	from messages import LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED, \
21			LAYER_CHANGED
22	bh	6
23			from color import Color
24
25	jonathan	437	import classification
26	bh	6
27			from base import TitledObject, Modifiable
28
29	bh	723
30	bh	6	class Shape:
31
32			"""Represent one shape"""
33
34			def __init__(self, points):
35			self.points = points
36			#self.compute_bbox()
37	jonathan	828	self.bbox = None
38	bh	6
39			def compute_bbox(self):
40	jonathan	828	if self.bbox is not None:
41			return self.bbox
42
43	bh	6	xs = []
44			ys = []
45			for x, y in self.points:
46			xs.append(x)
47			ys.append(y)
48			self.llx = min(xs)
49			self.lly = min(ys)
50			self.urx = max(xs)
51			self.ury = max(ys)
52
53	jonathan	828	self.bbox = (self.llx, self.lly, self.urx, self.ury)
54
55			return self.bbox
56
57	bh	6	def Points(self):
58			return self.points
59
60
61
62			# Shape type constants
63			SHAPETYPE_POLYGON = "polygon"
64			SHAPETYPE_ARC = "arc"
65			SHAPETYPE_POINT = "point"
66
67			# mapping from shapelib shapetype constants to our constants
68			shapelib_shapetypes = {shapelib.SHPT_POLYGON: SHAPETYPE_POLYGON,
69			shapelib.SHPT_ARC: SHAPETYPE_ARC,
70			shapelib.SHPT_POINT: SHAPETYPE_POINT}
71
72			shapetype_names = {SHAPETYPE_POINT: "Point",
73			SHAPETYPE_ARC: "Arc",
74			SHAPETYPE_POLYGON: "Polygon"}
75
76			class BaseLayer(TitledObject, Modifiable):
77
78			"""Base class for the layers."""
79
80	jonathan	929	def __init__(self, title, visible = True, projection = None):
81	bh	6	"""Initialize the layer.
82
83			title -- the title
84			visible -- boolean. If true the layer is visible.
85			"""
86			TitledObject.__init__(self, title)
87			Modifiable.__init__(self)
88			self.visible = visible
89	jonathan	929	self.projection = projection
90	bh	6
91			def Visible(self):
92			"""Return true if layer is visible"""
93			return self.visible
94
95			def SetVisible(self, visible):
96			"""Set the layer's visibility."""
97			self.visible = visible
98			self.issue(LAYER_VISIBILITY_CHANGED, self)
99	bh	276
100	jonathan	929	def HasClassification(self):
101			"""Determine if this layer support classifications."""
102			return False
103	bh	276
104	jonathan	929	def GetProjection(self):
105			"""Return the layer's projection."""
106			return self.projection
107
108			def SetProjection(self, projection):
109			"""Set the layer's projection"""
110			self.projection = projection
111			self.changed(LAYER_PROJECTION_CHANGED, self)
112
113	bh	6	class Layer(BaseLayer):
114
115			"""Represent the information of one geodata file (currently a shapefile)
116
117			All children of the layer have the same type.
118
119			A layer has fill and stroke colors. Colors should be instances of
120			Color. They can also be None, indicating no fill or no stroke.
121
122			The layer objects send the following events, all of which have the
123			layer object as parameter:
124
125			TITLE_CHANGED -- The title has changed.
126			LAYER_PROJECTION_CHANGED -- the projection has changed.
127			"""
128
129	bh	723	def __init__(self, title, data, projection = None,
130	jonathan	610	fill = Color.Transparent,
131	jonathan	412	stroke = Color.Black,
132	jonathan	464	lineWidth = 1,
133	jonathan	771	visible = True):
134	bh	6	"""Initialize the layer.
135
136			title -- the title
137	bh	723	data -- datastore object for the shape data shown by the layer
138	bh	6	projection -- the projection object. Its Inverse method is
139			assumed to map the layer's coordinates to lat/long
140			coordinates
141	jonathan	610	fill -- the fill color or Color.Transparent if the shapes are
142			not filled
143			stroke -- the stroke color or Color.Transparent if the shapes
144			are not stroked
145	bh	6	visible -- boolean. If true the layer is visible.
146
147			colors are expected to be instances of Color class
148			"""
149	jonathan	929	BaseLayer.__init__(self, title,
150			visible = visible,
151			projection = projection)
152	bh	276
153	jonathan	481	#
154			# this is really important so that when the classification class
155			# tries to set its parent layer the variable will exist
156			#
157	bh	723	self.__classification = None
158	jonathan	529	self.__setClassLock = False
159	jonathan	481
160	bh	723	self.SetShapeStore(data)
161	jonathan	492
162			self.SetClassification(None)
163
164	jonathan	464	self.__classification.SetDefaultLineColor(stroke)
165			self.__classification.SetDefaultLineWidth(lineWidth)
166	jonathan	412	self.__classification.SetDefaultFill(fill)
167	jonathan	492	self.__classification.SetLayer(self)
168	jonathan	364
169	jonathan	389	self.UnsetModified()
170
171	bh	6
172	bh	723	def SetShapeStore(self, store):
173			self.store = store
174			self.shapefile = self.store.Shapefile()
175			self.shapetable = self.store.Table()
176			self.filename = self.store.filename
177			self.table = self.shapetable
178	bh	179
179	bh	723	numshapes, shapetype, mins, maxs = self.shapefile.info()
180			self.numshapes = numshapes
181			self.shapetype = shapelib_shapetypes[shapetype]
182	bh	171
183	bh	723	# if there are shapes, set the bbox accordingly. Otherwise
184			# set it to None.
185			if self.numshapes:
186			self.bbox = mins[:2] + maxs[:2]
187			else:
188			self.bbox = None
189	bh	171
190	bh	723	# estimate a good depth for the quad tree. Each depth
191			# multiplies the number of nodes by four, therefore we
192			# basically take the base 4 logarithm of the number of
193			# shapes.
194			if self.numshapes < 4:
195			maxdepth = 1
196			else:
197			maxdepth = int(ceil(log(self.numshapes / 4.0) / log(4)))
198
199			self.shapetree = shptree.SHPTree(self.shapefile.cobject(), 2,
200			maxdepth)
201			if self.__classification is not None:
202			fieldname = self.__classification.GetField()
203	jan	791	if fieldname is not None and \
204	bh	839	not self.store.Table().HasColumn(fieldname):
205	bh	723	self.SetClassification(None)
206			self.changed(LAYER_CHANGED, self)
207
208			def ShapeStore(self):
209			return self.store
210
211	bh	258	def Destroy(self):
212	bh	260	BaseLayer.Destroy(self)
213	jonathan	529	self.SetClassification(None)
214	bh	258
215	bh	6	def BoundingBox(self):
216	bh	179	"""Return the layer's bounding box in the intrinsic coordinate system.
217
218			If the layer has no shapes, return None.
219			"""
220	bh	6	return self.bbox
221
222			def LatLongBoundingBox(self):
223	bh	179	"""Return the layer's bounding box in lat/long coordinates.
224	bh	6
225	bh	179	Return None, if the layer doesn't contain any shapes.
226			"""
227			bbox = self.BoundingBox()
228			if bbox is not None:
229			llx, lly, urx, ury = bbox
230			if self.projection is not None:
231			llx, lly = self.projection.Inverse(llx, lly)
232			urx, ury = self.projection.Inverse(urx, ury)
233			return llx, lly, urx, ury
234			else:
235			return None
236
237	jonathan	828	def ShapesBoundingBox(self, shapes):
238			"""Return a bounding box in lat/long coordinates for the given
239			list of shape ids.
240
241			If shapes is None or empty, return None.
242			"""
243
244			if shapes is None or len(shapes) == 0: return None
245
246			llx = []
247			lly = []
248			urx = []
249			ury = []
250
251			if self.projection is not None:
252			inverse = lambda x, y: self.projection.Inverse(x, y)
253			else:
254			inverse = lambda x, y: (x, y)
255
256			for id in shapes:
257			left, bottom, right, top = self.Shape(id).compute_bbox()
258
259			left, bottom = inverse(left, bottom)
260			right, top = inverse(right, top)
261
262			llx.append(left)
263			lly.append(bottom)
264			urx.append(right)
265			ury.append(top)
266
267			return (min(llx), min(lly), max(urx), max(ury))
268
269	jonathan	464	def GetFieldType(self, fieldName):
270	bh	839	if self.table.HasColumn(fieldName):
271			return self.table.Column(fieldName).type
272			return None
273	jonathan	464
274	bh	6	def NumShapes(self):
275			"""Return the number of shapes in the layer"""
276			return self.numshapes
277
278			def ShapeType(self):
279			"""Return the type of the shapes in the layer.
280			This is either SHAPETYPE_POINT, SHAPETYPE_ARC or SHAPETYPE_POLYGON.
281			"""
282			return self.shapetype
283
284			def Shape(self, index):
285			"""Return the shape with index index"""
286			shape = self.shapefile.read_object(index)
287	jonathan	364
288	bh	6	if self.shapetype == SHAPETYPE_POINT:
289			points = shape.vertices()
290			else:
291			#for poly in shape.vertices():
292			poly = shape.vertices()[0]
293			points = []
294			for x, y in poly:
295	bh	82	points.append((x, y))
296	jonathan	364
297	bh	6	return Shape(points)
298
299	bh	143	def ShapesInRegion(self, box):
300			"""Return the ids of the shapes that overlap the box.
301
302	jonathan	794	Box is a tuple (left, bottom, right, top) in unprojected coordinates.
303	bh	143	"""
304			left, bottom, right, top = box
305	jonathan	794
306			if self.projection is not None:
307			left, bottom = self.projection.Forward(left, bottom)
308			right, top = self.projection.Forward(right, top)
309
310	bh	147	return self.shapetree.find_shapes((left, bottom), (right, top))
311	bh	143
312	jonathan	929	def HasClassification(self):
313			return True
314	jonathan	725
315	jonathan	412	def GetClassification(self):
316			return self.__classification
317
318			def SetClassification(self, clazz):
319	jonathan	492	"""Set the classification to 'clazz'
320	jonathan	481
321	jonathan	492	If 'clazz' is None a default classification is created
322			"""
323	jonathan	481
324	jonathan	529	# prevent infinite recursion when calling SetLayer()
325			if self.__setClassLock: return
326
327			self.__setClassLock = True
328
329	jonathan	492	if clazz is None:
330	jonathan	529	if self.__classification is not None:
331			self.__classification.SetLayer(None)
332	jonathan	492	self.__classification = classification.Classification()
333			else:
334			self.__classification = clazz
335	jonathan	529	try:
336			self.__classification.SetLayer(self)
337			except ValueError:
338			self.__setClassLock = False
339			raise ValueError
340	jonathan	492
341	jonathan	545	self.changed(LAYER_CHANGED, self)
342	jonathan	412
343	jonathan	529	self.__setClassLock = False
344
345	jonathan	492	def ClassChanged(self):
346			"""Called from the classification object when it has changed."""
347	jonathan	558	self.changed(LAYER_CHANGED, self)
348	jonathan	492
349	bh	217	def TreeInfo(self):
350			items = []
351
352			if self.Visible():
353	jan	374	items.append(_("Shown"))
354	bh	217	else:
355	jan	374	items.append(_("Hidden"))
356			items.append(_("Shapes: %d") % self.NumShapes())
357	bh	217
358			bbox = self.LatLongBoundingBox()
359			if bbox is not None:
360	jan	374	items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
361	bh	217	else:
362	jan	374	items.append(_("Extent (lat-lon):"))
363			items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()])
364	bh	217
365	jonathan	736	if self.projection and len(self.projection.params) > 0:
366			items.append((_("Projection"),
367			[str(param) for param in self.projection.params]))
368
369	jonathan	412	items.append(self.__classification)
370	bh	217
371	jan	374	return (_("Layer '%s'") % self.Title(), items)
372	jonathan	382
373	jonathan	736
374	jonathan	929	class RasterLayer(BaseLayer):
375
376			def __init__(self, title, filename, projection = None, visible = True):
377			"""Initialize the Raster Layer.
378
379			title -- title for the layer.
380
381			filename -- file name of the source image.
382
383			projection -- Projection object describing the projection which
384			the source image is in.
385
386			visible -- True is the layer should initially be visible.
387	jonathan	961
388			Throws IOError if the filename is invalid or points to a file that
389			is not in a format GDAL can use.
390	jonathan	929	"""
391
392			BaseLayer.__init__(self, title, visible = visible)
393
394			self.projection = projection
395			self.filename = filename
396
397			self.bbox = -1
398
399	jonathan	961	#
400			# temporarily open the file so that GDAL can test if it's valid.
401			#
402			dataset = gdal.Open(self.filename, GA_ReadOnly)
403
404			if dataset is None:
405			raise IOError()
406
407	jonathan	929	self.UnsetModified()
408
409			def BoundingBox(self):
410			"""Return the layer's bounding box in the intrinsic coordinate system.
411
412			If the layer has no shapes, return None.
413			"""
414			if self.bbox == -1:
415			dataset = gdal.Open(self.filename, GA_ReadOnly)
416			if dataset is None:
417			self.bbox = None
418			else:
419	jonathan	961	geotransform = dataset.GetGeoTransform()
420			if geotransform is None:
421			return None
422
423			x = 0
424			y = dataset.RasterYSize
425			left = geotransform[0] + \
426			geotransform[1] * x + \
427			geotransform[2] * y
428
429			bottom = geotransform[3] + \
430			geotransform[4] * x + \
431			geotransform[5] * y
432
433			x = dataset.RasterXSize
434			y = 0
435			right = geotransform[0] + \
436			geotransform[1] * x + \
437			geotransform[2] * y
438
439			top = geotransform[3] + \
440			geotransform[4] * x + \
441			geotransform[5] * y
442
443	jonathan	929	self.bbox = (left, bottom, right, top)
444
445			return self.bbox
446
447			def LatLongBoundingBox(self):
448			bbox = self.BoundingBox()
449	jonathan	961	if bbox is None:
450	jonathan	929	return None
451
452	jonathan	961	llx, lly, urx, ury = bbox
453			if self.projection is not None:
454			llx, lly = self.projection.Inverse(llx, lly)
455			urx, ury = self.projection.Inverse(urx, ury)
456
457			return llx, lly, urx, ury
458
459	jonathan	929	def GetImageFilename(self):
460			return self.filename
461
462			def TreeInfo(self):
463			items = []
464
465			if self.Visible():
466			items.append(_("Shown"))
467			else:
468			items.append(_("Hidden"))
469			items.append(_("Shapes: %d") % self.NumShapes())
470
471			bbox = self.LatLongBoundingBox()
472			if bbox is not None:
473			items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
474			else:
475			items.append(_("Extent (lat-lon):"))
476
477			if self.projection and len(self.projection.params) > 0:
478			items.append((_("Projection"),
479			[str(param) for param in self.projection.params]))
480
481			return (_("Layer '%s'") % self.Title(), items)
482
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svn:keywords	Author Date Id Revision