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__ = "$Revision$"

import warnings

from Thuban import _

from messages import LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED, \
     LAYER_CHANGED, LAYER_SHAPESTORE_REPLACED, CLASS_CHANGED

import classification

from color import Transparent, Black
from base import TitledObject, Modifiable
from data import SHAPETYPE_POLYGON, SHAPETYPE_ARC, SHAPETYPE_POINT

import resource


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 HasShapes(self):
        """Determine if this layer supports shapes."""
        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 Transparent, 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 = Transparent, 
                 stroke = 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 Transparent if the shapes are 
                not filled
        stroke -- the stroke color or 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)

        self.__classification = None
        self.store = None

        self.SetShapeStore(data)

        self.classification_column = None
        self.SetClassificationColumn(None)
        self.SetClassification(None)

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

        self.UnsetModified()

    def __getattr__(self, attr):
        """Access to some attributes for backwards compatibility

        The attributes implemented here are now held by the shapestore
        if at all. For backwards compatibility pretend that they are
        still there but issue a DeprecationWarning when they are
        accessed.
        """
        if attr in ("table", "shapetable"):
            value = self.store.Table()
        elif attr == "shapefile":
            value = self.store.Shapefile()
        elif attr == "filename":
            value = self.store.FileName()
        else:
            raise AttributeError, attr
        warnings.warn("The Layer attribute %r is deprecated."
                      " It's value can be accessed through the shapestore"
                      % attr, DeprecationWarning, stacklevel = 2)
        return value

    def SetShapeStore(self, store):
        # Set the classification to None if there is a classification
        # and the new shapestore doesn't have a table with a suitable
        # column, i.e one with the same name and type as before
        # FIXME: Maybe we should keep it the same if the type is
        # compatible enough such as FIELDTYPE_DOUBLE and FIELDTYPE_INT
        if self.__classification is not None:
            columnname = self.classification_column
            columntype = self.GetFieldType(columnname)
            table = store.Table()
            if (columnname is not None
                and (not table.HasColumn(columnname)
                     or table.Column(columnname).type != columntype)):
                self.SetClassification(None)

        self.store = store

        self.changed(LAYER_SHAPESTORE_REPLACED, self)

    def ShapeStore(self):
        return self.store

    def Destroy(self):
        BaseLayer.Destroy(self)
        if self.__classification is not None:
            self.__classification.Unsubscribe(CLASS_CHANGED,
                                              self._classification_changed)

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

        If the layer has no shapes, return None.
        """
        return self.store.BoundingBox()

    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.store:
            table = self.store.Table()
            if table.HasColumn(fieldName):
                return table.Column(fieldName).type
        return None

    def HasShapes(self):
        return True

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

    def ShapeType(self):
        """Return the type of the shapes in the layer.

        The return value is one of the SHAPETYPE_* constants defined in
        Thuban.Model.data.
        """
        return self.store.ShapeType()

    def Shape(self, index):
        """Return the shape with index index"""
        return self.store.Shape(index)

    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.store.ShapesInRegion((left, bottom, right, top))

    def GetClassificationColumn(self):
        return self.classification_column

    def SetClassificationColumn(self, column):
        """Set the column to classifiy on, or None. If column is not None
        and the column does not exist in the table, raise a ValueError.
        """
        if column:
            columnType = self.GetFieldType(column)
            if columnType is None:
                raise ValueError()
        changed = self.classification_column != column
        self.classification_column = column
        if changed:
            self.changed(LAYER_CHANGED, self)

    def HasClassification(self):
        return True

    def GetClassification(self):
        return self.__classification

    def SetClassification(self, clazz):
        """Set the classification used by this layer to 'clazz'

        If 'clazz' is None a default classification is created.

        This issues a LAYER_CHANGED event.
        """

        if self.__classification is not None:
            self.__classification.Unsubscribe(CLASS_CHANGED,
                                              self._classification_changed)

        if clazz is None:
            clazz = classification.Classification()

        self.__classification = clazz
        self.__classification.Subscribe(CLASS_CHANGED,
                                        self._classification_changed)

        self._classification_changed()

    def _classification_changed(self):
        """Called from the classification object when it has changed."""
        self.changed(LAYER_CHANGED, self)
 
    def TreeInfo(self):
        items = []

        items.append(_("Filename: %s") % self.ShapeStore().FileName())

        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)


if resource.has_gdal_support():
    import gdal
    from gdalconst import GA_ReadOnly

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

        if resource.has_gdal_support():
            #
            # 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 there is no support for images, or the file cannot
        be read, or there is no geographics information available, return None.
        """
        if not resource.has_gdal_support():
            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 = []

        items.append(_("Filename: %s") % self.GetImageFilename())

        if self.Visible():
            items.append(_("Shown"))
        else:
            items.append(_("Hidden"))

        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	1219	import warnings
12	bh	171
13	jan	374	from Thuban import _
14	bh	6
15	bh	701	from messages import LAYER_PROJECTION_CHANGED, LAYER_VISIBILITY_CHANGED, \
16	jonathan	1427	LAYER_CHANGED, LAYER_SHAPESTORE_REPLACED, CLASS_CHANGED
17	bh	6
18	jonathan	437	import classification
19	bh	6
20	jonathan	1338	from color import Transparent, Black
21	bh	6	from base import TitledObject, Modifiable
22	bh	1558	from data import SHAPETYPE_POLYGON, SHAPETYPE_ARC, SHAPETYPE_POINT
23	bh	6
24	jonathan	1158	import resource
25	bh	723
26	jonathan	1158
27	bh	6	shapetype_names = {SHAPETYPE_POINT: "Point",
28			SHAPETYPE_ARC: "Arc",
29			SHAPETYPE_POLYGON: "Polygon"}
30
31			class BaseLayer(TitledObject, Modifiable):
32
33			"""Base class for the layers."""
34
35	jonathan	929	def __init__(self, title, visible = True, projection = None):
36	bh	6	"""Initialize the layer.
37
38			title -- the title
39			visible -- boolean. If true the layer is visible.
40			"""
41			TitledObject.__init__(self, title)
42			Modifiable.__init__(self)
43			self.visible = visible
44	jonathan	929	self.projection = projection
45	bh	6
46			def Visible(self):
47			"""Return true if layer is visible"""
48			return self.visible
49
50			def SetVisible(self, visible):
51			"""Set the layer's visibility."""
52			self.visible = visible
53			self.issue(LAYER_VISIBILITY_CHANGED, self)
54	bh	276
55	jonathan	929	def HasClassification(self):
56			"""Determine if this layer support classifications."""
57			return False
58	bh	276
59	jonathan	1273	def HasShapes(self):
60			"""Determine if this layer supports shapes."""
61			return False
62
63	jonathan	929	def GetProjection(self):
64			"""Return the layer's projection."""
65			return self.projection
66
67			def SetProjection(self, projection):
68			"""Set the layer's projection"""
69			self.projection = projection
70			self.changed(LAYER_PROJECTION_CHANGED, self)
71
72	bh	6	class Layer(BaseLayer):
73
74			"""Represent the information of one geodata file (currently a shapefile)
75
76			All children of the layer have the same type.
77
78			A layer has fill and stroke colors. Colors should be instances of
79	jonathan	1338	Color. They can also be Transparent, indicating no fill or no stroke.
80	bh	6
81			The layer objects send the following events, all of which have the
82			layer object as parameter:
83
84			TITLE_CHANGED -- The title has changed.
85			LAYER_PROJECTION_CHANGED -- the projection has changed.
86			"""
87
88	bh	723	def __init__(self, title, data, projection = None,
89	jonathan	1338	fill = Transparent,
90			stroke = Black,
91	jonathan	464	lineWidth = 1,
92	jonathan	771	visible = True):
93	bh	6	"""Initialize the layer.
94
95			title -- the title
96	bh	723	data -- datastore object for the shape data shown by the layer
97	bh	6	projection -- the projection object. Its Inverse method is
98			assumed to map the layer's coordinates to lat/long
99			coordinates
100	jonathan	1338	fill -- the fill color or Transparent if the shapes are
101	jonathan	610	not filled
102	jonathan	1338	stroke -- the stroke color or Transparent if the shapes
103	jonathan	610	are not stroked
104	bh	6	visible -- boolean. If true the layer is visible.
105
106			colors are expected to be instances of Color class
107			"""
108	jonathan	929	BaseLayer.__init__(self, title,
109			visible = visible,
110			projection = projection)
111	bh	276
112	bh	723	self.__classification = None
113	jonathan	1427	self.store = None
114	jonathan	481
115	bh	723	self.SetShapeStore(data)
116	jonathan	492
117	bh	1452	self.classification_column = None
118			self.SetClassificationColumn(None)
119	jonathan	492	self.SetClassification(None)
120
121	jonathan	464	self.__classification.SetDefaultLineColor(stroke)
122			self.__classification.SetDefaultLineWidth(lineWidth)
123	jonathan	412	self.__classification.SetDefaultFill(fill)
124	jonathan	364
125	jonathan	389	self.UnsetModified()
126
127	bh	1219	def __getattr__(self, attr):
128			"""Access to some attributes for backwards compatibility
129	bh	6
130	bh	1219	The attributes implemented here are now held by the shapestore
131			if at all. For backwards compatibility pretend that they are
132			still there but issue a DeprecationWarning when they are
133			accessed.
134			"""
135			if attr in ("table", "shapetable"):
136			value = self.store.Table()
137			elif attr == "shapefile":
138			value = self.store.Shapefile()
139			elif attr == "filename":
140			value = self.store.FileName()
141			else:
142			raise AttributeError, attr
143			warnings.warn("The Layer attribute %r is deprecated."
144			" It's value can be accessed through the shapestore"
145			% attr, DeprecationWarning, stacklevel = 2)
146			return value
147
148	bh	723	def SetShapeStore(self, store):
149	jonathan	1427	# Set the classification to None if there is a classification
150			# and the new shapestore doesn't have a table with a suitable
151			# column, i.e one with the same name and type as before
152			# FIXME: Maybe we should keep it the same if the type is
153			# compatible enough such as FIELDTYPE_DOUBLE and FIELDTYPE_INT
154			if self.__classification is not None:
155	bh	1452	columnname = self.classification_column
156			columntype = self.GetFieldType(columnname)
157	jonathan	1427	table = store.Table()
158	bh	1452	if (columnname is not None
159			and (not table.HasColumn(columnname)
160			or table.Column(columnname).type != columntype)):
161	jonathan	1427	self.SetClassification(None)
162
163	bh	723	self.store = store
164	bh	179
165	bh	1142	self.changed(LAYER_SHAPESTORE_REPLACED, self)
166	bh	723
167			def ShapeStore(self):
168			return self.store
169
170	bh	258	def Destroy(self):
171	bh	260	BaseLayer.Destroy(self)
172	jonathan	1427	if self.__classification is not None:
173	bh	1452	self.__classification.Unsubscribe(CLASS_CHANGED,
174			self._classification_changed)
175	bh	258
176	bh	6	def BoundingBox(self):
177	bh	179	"""Return the layer's bounding box in the intrinsic coordinate system.
178
179			If the layer has no shapes, return None.
180			"""
181	bh	1535	return self.store.BoundingBox()
182	bh	6
183			def LatLongBoundingBox(self):
184	bh	179	"""Return the layer's bounding box in lat/long coordinates.
185	bh	6
186	bh	179	Return None, if the layer doesn't contain any shapes.
187			"""
188			bbox = self.BoundingBox()
189			if bbox is not None:
190			llx, lly, urx, ury = bbox
191			if self.projection is not None:
192			llx, lly = self.projection.Inverse(llx, lly)
193			urx, ury = self.projection.Inverse(urx, ury)
194			return llx, lly, urx, ury
195			else:
196			return None
197
198	jonathan	828	def ShapesBoundingBox(self, shapes):
199			"""Return a bounding box in lat/long coordinates for the given
200			list of shape ids.
201
202			If shapes is None or empty, return None.
203			"""
204
205			if shapes is None or len(shapes) == 0: return None
206
207			llx = []
208			lly = []
209			urx = []
210			ury = []
211
212			if self.projection is not None:
213			inverse = lambda x, y: self.projection.Inverse(x, y)
214			else:
215			inverse = lambda x, y: (x, y)
216
217			for id in shapes:
218			left, bottom, right, top = self.Shape(id).compute_bbox()
219
220			left, bottom = inverse(left, bottom)
221			right, top = inverse(right, top)
222
223			llx.append(left)
224			lly.append(bottom)
225			urx.append(right)
226			ury.append(top)
227
228			return (min(llx), min(lly), max(urx), max(ury))
229
230	jonathan	464	def GetFieldType(self, fieldName):
231	jonathan	1427	if self.store:
232			table = self.store.Table()
233			if table.HasColumn(fieldName):
234			return table.Column(fieldName).type
235	bh	839	return None
236	jonathan	464
237	jonathan	1273	def HasShapes(self):
238			return True
239
240	bh	6	def NumShapes(self):
241			"""Return the number of shapes in the layer"""
242	bh	1535	return self.store.NumShapes()
243	bh	6
244			def ShapeType(self):
245			"""Return the type of the shapes in the layer.
246	bh	1535
247			The return value is one of the SHAPETYPE_* constants defined in
248			Thuban.Model.data.
249	bh	6	"""
250	bh	1535	return self.store.ShapeType()
251	bh	6
252			def Shape(self, index):
253			"""Return the shape with index index"""
254	bh	1535	return self.store.Shape(index)
255	jonathan	364
256	bh	143	def ShapesInRegion(self, box):
257			"""Return the ids of the shapes that overlap the box.
258
259	jonathan	794	Box is a tuple (left, bottom, right, top) in unprojected coordinates.
260	bh	143	"""
261			left, bottom, right, top = box
262	jonathan	794
263			if self.projection is not None:
264			left, bottom = self.projection.Forward(left, bottom)
265			right, top = self.projection.Forward(right, top)
266
267	bh	1535	return self.store.ShapesInRegion((left, bottom, right, top))
268	bh	143
269	bh	1452	def GetClassificationColumn(self):
270			return self.classification_column
271	jonathan	1427
272	bh	1452	def SetClassificationColumn(self, column):
273			"""Set the column to classifiy on, or None. If column is not None
274			and the column does not exist in the table, raise a ValueError.
275	jonathan	1427	"""
276	bh	1452	if column:
277			columnType = self.GetFieldType(column)
278			if columnType is None:
279	jonathan	1427	raise ValueError()
280	bh	1452	changed = self.classification_column != column
281			self.classification_column = column
282			if changed:
283			self.changed(LAYER_CHANGED, self)
284	jonathan	1427
285	jonathan	929	def HasClassification(self):
286			return True
287	jonathan	725
288	jonathan	412	def GetClassification(self):
289			return self.__classification
290
291			def SetClassification(self, clazz):
292	jonathan	1338	"""Set the classification used by this layer to 'clazz'
293	jonathan	481
294	jonathan	1338	If 'clazz' is None a default classification is created.
295
296	jonathan	1427	This issues a LAYER_CHANGED event.
297	jonathan	492	"""
298	jonathan	481
299	jonathan	1427	if self.__classification is not None:
300	bh	1452	self.__classification.Unsubscribe(CLASS_CHANGED,
301			self._classification_changed)
302	jonathan	529
303	jonathan	1338	if clazz is None:
304			clazz = classification.Classification()
305	jonathan	529
306	jonathan	1427	self.__classification = clazz
307	bh	1452	self.__classification.Subscribe(CLASS_CHANGED,
308			self._classification_changed)
309	jonathan	1338
310	bh	1452	self._classification_changed()
311	jonathan	492
312	bh	1452	def _classification_changed(self):
313	jonathan	492	"""Called from the classification object when it has changed."""
314	jonathan	558	self.changed(LAYER_CHANGED, self)
315	jonathan	492
316	bh	217	def TreeInfo(self):
317			items = []
318
319	jonathan	1338	items.append(_("Filename: %s") % self.ShapeStore().FileName())
320	jan	1012
321	bh	217	if self.Visible():
322	jan	374	items.append(_("Shown"))
323	bh	217	else:
324	jan	374	items.append(_("Hidden"))
325			items.append(_("Shapes: %d") % self.NumShapes())
326	bh	217
327			bbox = self.LatLongBoundingBox()
328			if bbox is not None:
329	jan	374	items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
330	bh	217	else:
331	jan	374	items.append(_("Extent (lat-lon):"))
332			items.append(_("Shapetype: %s") % shapetype_names[self.ShapeType()])
333	bh	217
334	jonathan	736	if self.projection and len(self.projection.params) > 0:
335			items.append((_("Projection"),
336			[str(param) for param in self.projection.params]))
337
338	jonathan	412	items.append(self.__classification)
339	bh	217
340	jan	374	return (_("Layer '%s'") % self.Title(), items)
341	jonathan	382
342	jonathan	736
343	jonathan	1158	if resource.has_gdal_support():
344			import gdal
345			from gdalconst import GA_ReadOnly
346
347	jonathan	929	class RasterLayer(BaseLayer):
348
349			def __init__(self, title, filename, projection = None, visible = True):
350			"""Initialize the Raster Layer.
351
352			title -- title for the layer.
353
354			filename -- file name of the source image.
355
356			projection -- Projection object describing the projection which
357			the source image is in.
358
359			visible -- True is the layer should initially be visible.
360	jonathan	961
361			Throws IOError if the filename is invalid or points to a file that
362			is not in a format GDAL can use.
363	jonathan	929	"""
364
365			BaseLayer.__init__(self, title, visible = visible)
366
367			self.projection = projection
368			self.filename = filename
369
370			self.bbox = -1
371
372	jonathan	1158	if resource.has_gdal_support():
373			#
374			# temporarily open the file so that GDAL can test if it's valid.
375			#
376			dataset = gdal.Open(self.filename, GA_ReadOnly)
377	jonathan	961
378	jonathan	1158	if dataset is None:
379			raise IOError()
380	jonathan	961
381	jonathan	929	self.UnsetModified()
382
383			def BoundingBox(self):
384			"""Return the layer's bounding box in the intrinsic coordinate system.
385
386	jonathan	1338	If the there is no support for images, or the file cannot
387			be read, or there is no geographics information available, return None.
388	jonathan	929	"""
389	jonathan	1158	if not resource.has_gdal_support():
390			return None
391
392	jonathan	929	if self.bbox == -1:
393			dataset = gdal.Open(self.filename, GA_ReadOnly)
394			if dataset is None:
395			self.bbox = None
396			else:
397	jonathan	961	geotransform = dataset.GetGeoTransform()
398			if geotransform is None:
399			return None
400
401			x = 0
402			y = dataset.RasterYSize
403			left = geotransform[0] + \
404			geotransform[1] * x + \
405			geotransform[2] * y
406
407			bottom = geotransform[3] + \
408			geotransform[4] * x + \
409			geotransform[5] * y
410
411			x = dataset.RasterXSize
412			y = 0
413			right = geotransform[0] + \
414			geotransform[1] * x + \
415			geotransform[2] * y
416
417			top = geotransform[3] + \
418			geotransform[4] * x + \
419			geotransform[5] * y
420
421	jonathan	929	self.bbox = (left, bottom, right, top)
422
423			return self.bbox
424
425			def LatLongBoundingBox(self):
426			bbox = self.BoundingBox()
427	jonathan	961	if bbox is None:
428	jonathan	929	return None
429
430	jonathan	961	llx, lly, urx, ury = bbox
431			if self.projection is not None:
432			llx, lly = self.projection.Inverse(llx, lly)
433			urx, ury = self.projection.Inverse(urx, ury)
434
435			return llx, lly, urx, ury
436
437	jonathan	929	def GetImageFilename(self):
438			return self.filename
439
440			def TreeInfo(self):
441			items = []
442
443	jonathan	1338	items.append(_("Filename: %s") % self.GetImageFilename())
444
445	jonathan	929	if self.Visible():
446			items.append(_("Shown"))
447			else:
448			items.append(_("Hidden"))
449
450			bbox = self.LatLongBoundingBox()
451			if bbox is not None:
452			items.append(_("Extent (lat-lon): (%g, %g, %g, %g)") % bbox)
453			else:
454			items.append(_("Extent (lat-lon):"))
455
456			if self.projection and len(self.projection.params) > 0:
457			items.append((_("Projection"),
458			[str(param) for param in self.projection.params]))
459
460			return (_("Layer '%s'") % self.Title(), items)
461
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svn:keywords	Author Date Id Revision