Extensions/ogr/ogrshapes.py

# Copyright (C) 2004 by Intevation GmbH
# Authors:
# Nina Hueffmeyer <[email protected]>
#
# This program is free software under the GPL (>=v2)
# Read the file COPYING coming with the software for details.

__version__ = "$Revision$"
# $Source$
# $Id$

from __future__ import generators

try:
    import ogr
except ImportError:
    ogr = None

import os

from Thuban import _
from Thuban.Model import table
from Thuban.Model import transientdb
from Thuban.Model.transientdb import  TransientDatabase

from Thuban.Model.data import SHAPETYPE_POLYGON, SHAPETYPE_ARC, SHAPETYPE_POINT
from Thuban.Model.data import RAW_PYTHON, RAW_SHAPEFILE, RAW_WKT

def has_ogr_support():
    """Return whether this Thuban instance supports ogr file formats

    Having OGR support means that the ogr module can be
    imported.
    """
    return ogr is not None

if ogr is not None:
    SHAPETYPE_UNKNOWN = ogr.wkbUnknown
    SHAPETYPE_GEOMCOLL = ogr.wkbGeometryCollection
    SHAPETYPE_NONE = ogr.wkbNone

    # mapping from ogr-lib shapetypes and table constants to our constants
    ogrlib_shapetypes = {ogr.wkbPolygon: SHAPETYPE_POLYGON,
                ogr.wkbLineString: SHAPETYPE_ARC,
                ogr.wkbPoint: SHAPETYPE_POINT,
                ogr.wkbUnknown: SHAPETYPE_UNKNOWN,
                ogr.wkbNone: SHAPETYPE_NONE,
                ogr.wkbGeometryCollection: SHAPETYPE_GEOMCOLL}

    fieldtype_map = {ogr.OFTString: table.FIELDTYPE_STRING,
                ogr.OFTInteger: table.FIELDTYPE_INT,
                ogr.OFTReal: table.FIELDTYPE_DOUBLE}

else:
    ogrlib_shapetypes = {}
    fieldtype_map = {}
    SHAPETYPE_UNKNOWN = 0
    SHAPETYPE_GEOMCOLL = 7
    SHAPETYPE_NONE = 100


class OGRShape:
    """Represent one shape of an OGRShapeStore
    """

    def __init__(self, shapestore, shape):
        """Initialize the shape object.

        shapestore should be an instance of OGRShapeStore,
        shape should be an instance of an OGRFeature.
        """
        self.ogrlayer = shapestore.ogrlayer
        id_column = shapestore.Id_column()
        self.feature = shape
        if id_column is None:
            self.shapeid = self.feature.GetFID()
        else:
            self.shapeid = self.feature.GetField(id_column)
        self.geom = self.feature.GetGeometryRef()
        if self.geom:
            self.shapetype = self.geom.GetGeometryType()
            self.bbox = self._compute_bbox()
            self.points = self._points()
        else:
            self.shapetype = ogr.wkbNone
            self.bbox = None
            self.points = [[]]
        try:
            self.shapetype = ogrlib_shapetypes[self.shapetype]
        except:
            self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]

        self.geoms = self._geoms()

    def _geoms(self):
        """Return a list of geometry objects.

        If the shape is a geometry collection, all contained geometry
        objects are stored to the list as OGRGeometry objects.
        """
        geoms = []
        if self.shapetype == SHAPETYPE_GEOMCOLL:
            for i in range(self.geom.GetGeometryCount()):
                geoms.append(OGRGeometry(self, self.geom, i))
        return geoms

    def _compute_bbox(self):
        """
        Compute the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
        """
        minx, maxx, miny, maxy = self.geom.GetEnvelope()
        return (minx, miny, maxx, maxy)

    def compute_bbox(self):
        """
        Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
        """
        return self.bbox

    def ShapeID(self):
        """Return the feature id of this shape.
        """
        return self.shapeid

    def Points(self):
        """Return the coordinates of the shape as a list of lists of pairs
        """
        return self.points

    def _points(self):
        """Get the coordinates of the shape as a list of lists of pairs
        """
        shape = []

        if self.geom is None:
            return shape.append([])

        # if geometry object is of type point or line
        if self.geom.GetGeometryCount() == 0:
            points =[]
            for point in range(self.geom.GetPointCount()):
                x = self.geom.GetX(point)
                y = self.geom.GetY(point)
                points.append((x, y))
            return [points]
        # if geometry object is of type polygon or multipolygon
        for i in range(self.geom.GetGeometryCount()):
            points = []
            geometry = self.geom.GetGeometryRef(i)
            # if geometry object is polygon
            if geometry.GetGeometryCount() == 0:
                for point in range(geometry.GetPointCount()):
                    x = geometry.GetX(point)
                    y = geometry.GetY(point)
                    points.append((x, y))
                shape.append(points)
            # if geometry object is of type multipolygon or geometry collection
            else:
                for j in range(geometry.GetGeometryCount()):
                    points = []
                    subgeom = geometry.GetGeometryRef(j)
                    for point in range(subgeom.GetPointCount()):
                        x = subgeom.GetX(point)
                        y = subgeom.GetY(point)
                        points.append((x, y))
                    shape.append(points)
        return shape

    def RawData(self):
        """Return the shape id to use with the shapestore
        """
        return self.shapeid

    def OGRLayer(self):
        """Return the ogrlayer object
        """
        return self.ogrlayer

    def ShapeType(self):
        """Return the shapetype of this shape (may differ from the layer's
        shapetype)
        """
        return self.shapetype

    def GetGeoms(self):
        """Return the list of geometries of this feature.

        If this feature is a geometry collection, all contained geometries
        are given. Else the returned list is empty.
        """
        return self.geoms

    def GetGeom(self, index):
        """Return the OGRGeometry object at the specified index.

        This is not none only if the shape is a geometry collection.
        """
        if index < len(self.geoms):
            return self.geoms[index]
        else:
            return None


class OGRGeometry:
    """This class represents a geometry belonging to a specified feature.
    """

    def __init__(self, shape, geom, index):
        """Initialize the geometry object.

        shape should be an OGRShape, which this geometry belongs to.
        geom is the base geometry, index is the ReferenceID.
        """
        self.shape = shape
        self.index = index

        self.geom = geom.GetGeometryRef(index)
        try:
            self.shapetype = ogrlib_shapetypes[self.geom.GetGeometryType()]
        except:
            self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]


    def ShapeType(self):
        """Return the shapetype of this geometry object."""
        return self.shapetype


class OGRShapeStore:
    """Corresponds to an OGRLayer object, containing features/shapes and
       providing the same methods like ShapefileStore.
    """

    def __init__(self, session, filename, layername, id_column = None):
        """Initialize the shapestore.

        All required information is loaded from the datasource.
        """
        # if id_column is None, data is loaded from file, so we need path
        # if id_column is not None, data is loaded from database
        if id_column is None:
            self.filename = os.path.abspath(filename)
        else:
            self.filename = filename
        self.layername = layername

        self.ogrdatasource = ogr.Open(filename)
        self.ogrlayer = (self.ogrdatasource).GetLayerByName(layername)

        if id_column is not None:
            self.id_column = id_column
        else:
            self.id_column = None

        self.table = OGRTable(session, self.ogrdatasource, self.ogrlayer,
                                self.id_column)

        self._open_ogrlayer(layername)

    def _open_ogrlayer(self, layername):
        """Get all required information from the datasource.
        """
        self.numshapes = self.ogrlayer.GetFeatureCount()
        self.shapetype = self.ogrlayer.GetLayerDefn().GetGeomType()

        extent = self.ogrlayer.GetExtent()
        if extent:
            self.bbox = [extent[0], extent[2], extent[1], extent[3]]
        else:
            self.bbox = None

        try:
            self.shapetype = ogrlib_shapetypes[self.shapetype]
        except:
            # if shapetype is not contained in ogrlib_shapetypes
            # treat it like SHAPETYPE_UNKNOWN
            self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]

        self.shapes = self.shapes()

    def shapes(self):
        """Return a collection of all features as OGRShape objects.
        """
        shapes = {}
        self.ogrlayer.ResetReading()
        if self.id_column is None:
            nextFeature = self.ogrlayer.GetNextFeature()
            while nextFeature is not None:
                fid = nextFeature.GetFID()
                shape = OGRShape(self, nextFeature)
                shapes[shape.ShapeID()] = shape
                nextFeature = self.ogrlayer.GetNextFeature()
        else:
            lay = self.ogrdatasource.ExecuteSQL("SELECT %s, * from %s" 
                                    % (self.id_column, self.layername))
            if lay is not None:
                lay.ResetReading()
                nextFeature = lay.GetNextFeature()
                while nextFeature is not None:
                    fid = nextFeature.GetField(0)
                    shape = OGRShape(self, nextFeature)
                    shapes[shape.ShapeID()] = shape
                    nextFeature = lay.GetNextFeature()
                self.ogrdatasource.ReleaseResultSet(lay)
        return shapes

    def OGRLayer(self):
        """Return the OGRLayer object
        """
        return self.ogrlayer

    def FileName(self):
        """Return the filename used to open the file
        """
        return self.filename

    def FileType(self):
        """Return the filetype. This is depending on the driver used to open
        the file.
        """
        return self.ogrdatasource.GetDriver().GetName()

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

        This is either SHAPETYPE_POINT, SHAPETYPE_ARC, SHAPETYPE_POLYGON,
        SHAEPTYPE_GEOMCOLL, SHAPETYPE_NONE or SHAPETYPE_UNKNOWN.
        """
        return self.shapetype

    def RawShapeFormat(self):
        """Return the raw data format of the shape data, i.e. RAW_PYTHON
        """
        return RAW_PYTHON

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

    def BoundingBox(self):
        """Return the bounding box of the shapes in the shapestore.
        """
        return self.bbox

    def ShapesInRegion(self, bbox):
        """Return an iterable over the shapes that overlap the bounding box.

        The bbox parameter should be the bounding box as a tuple in the
        form (minx, miny, maxx, maxy) in the coordinate system of the
        shape store.
        """
        left, bottom, right, top = bbox

        # create a geometry which can be passed to the layer as spatial filter
        bboxpolygon = ogr.CreateGeometryFromWkt(
                      ('Polygon((%s %s, %s %s, %s %s,%s %s, %s %s))'
                                 %(left, bottom, left, top, right, top,
                                  right, bottom, left, bottom)))

        if self.ogrlayer.GetSpatialRef():
            bboxpolygon.AssignSpatialReference(self.ogrlayer.GetSpatialRef())

        self.ogrlayer.ResetReading()
        #ogrlayer.SetSpatialFilterRect(left, bottom, right, top)
        self.ogrlayer.SetSpatialFilter(bboxpolygon)

        numFeatures = self.ogrlayer.GetFeatureCount()
        # if no features are in bbox, return all features as shapesInRegion
        # (PostGIS sometimes returns no features even if they are within 
        #  the bounding box)
        if numFeatures == 0:
            self.ogrlayer.SetSpatialFilter(None)
            numFeatures = self.ogrlayer.GetFeatureCount()
        for feature in range(numFeatures):
            nextFeature = self.ogrlayer.GetNextFeature()
            if self.id_column is None:
                yield self.shapes[nextFeature.GetFID()]
            else:
                yield self.shapes[nextFeature.GetField(self.id_column)]

        self.ogrlayer.SetSpatialFilter(None)
        bboxpolygon.Destroy()

    def AllShapes(self):
        """Return an iterable over the shapes in the shape store.
        """
        for id in range(len(self.shapes)):
            yield self.shapes[id]

    def Shape(self, fid):
        """Return the shape with fid = fid
        """
        if fid in self.table.ids.keys():
            return self.shapes[fid]
        else:
            return None

    def Table(self):
        """Return the table containing the attribute data
        """
        return self.table

    def Dependencies(self):
        """Return the empty tuple.
        """
        return ()

    def OrigShapeStore(self):
        """Return None."""
        return None

    def Id_column(self):
        """Return the id_column.
        """
        return self.id_column

class OGRTable(transientdb.AutoTransientTable):
    """A Table for an ogr datasource.
    """

    def __init__(self, session, ds, layer, id_column):
        """Initialize the OGRTable.

        session   - should be the current session.
        ds        - should be an instance of OGRDatasource.
        layer     - should be an instance of OGRLayer.
        id_column - should be the name of the column used as ID column
        """
        self.datasource = ds
        self.layer = layer
        self.tablename = self.layer.GetName()
        self.id_column = id_column

        # Map column names and indices to column objects.
        self.column_map = {}

        # Map feature ids to ordinals.
        self._map_ords_and_ids()

        self._fetch_table_information()
        self._fetch_table_content()

        transientdb.AutoTransientTable.__init__(self, session.TransientDB(),
                                                self)

    def _fetch_table_information(self):
        """Internal: Update information about the table
        """
        self.columns = []

        layerdefn = self.layer.GetLayerDefn()
        # if FID column is of interest
        #col = OGRColumn("FID", table.FIELDTYPE_INT, layerdefn.GetFieldCount())
        #self.columns.append(col)
        for i in range(layerdefn.GetFieldCount()):
            fielddef = layerdefn.GetFieldDefn(i)
            fieldname = fielddef.GetName()
            fieldtype = fieldtype_map[fielddef.GetType()]
            fieldindex = layerdefn.GetFieldIndex(fieldname)
            col = OGRColumn(fieldname, fieldtype, fieldindex)
            if col is not None:
                self.columns.append(col)

        for col in self.columns:
            self.column_map[col.name] = col
            self.column_map[col.index] = col

    def _fetch_table_content(self):
        """Internal: Update information contained in the table
        """
        self.content = []
        layerdefn = self.layer.GetLayerDefn()

        self.layer.ResetReading()
        for i in range(self.layer.GetFeatureCount()):
            nextFeature = self.layer.GetNextFeature()
            row = []
            for j in range(layerdefn.GetFieldCount()):
                row.append(nextFeature.GetField(j))
            # if FID should be listed in the table
            #if self.id_column is None:
            #    row.append(nextFeature.GetFID())
            #else:
            #    row.append(nextFeature.GetField(self.id_column))
            self.content.append(row)

    def _map_ords_and_ids(self):
        """Create collections which map ordinals to ids and verse visa.
        """
        self.ordinals = {}
        self.ids = {}

        if self.id_column is not None:
            lay = self.datasource.ExecuteSQL("SELECT %s from %s"
                    %(self.id_column, self.tablename))
            lay.ResetReading()
            nextFeature = lay.GetNextFeature()
        else:
            self.layer.ResetReading()
            nextFeature = self.layer.GetNextFeature()

        ord = 0
        while nextFeature is not None:
            if self.id_column is not None:
                id = nextFeature.GetField(self.id_column)
                nextFeature = lay.GetNextFeature()
            else:
                id = nextFeature.GetFID()
                nextFeature = self.layer.GetNextFeature()
            self.ordinals[ord] = id
            self.ids[id] = ord
            ord = ord + 1
        if self.id_column is not None:
            self.datasource.ReleaseResultSet(lay)

    def TableName(self):
        """Return the name of the table, which is the name of the layer
        """
        return self.tablename

    def Title(self):
        """Return the title of the table.
        """
        return self.tablename

    def Dependencies(self):
        """Return an empty tuple.
        """
        return ()

    def NumColumns(self):
        """Return the number of columns.
        """
        return len(self.columns)

    def Columns(self):
        """Return all columns.
        """
        return self.columns

    def Column(self, col):
        """Return the column col. col can be either a string or an integer.
        """
        return self.column_map[col]

    def HasColumn(self, col):
        """Return if column col exists. col can be either a string or an
        integer.
        """
        return self.column_map.has_key(col)

    def NumRows(self):
        """Return the number of rows in the table, which equals the number of
        features in the layer.
        """
        return len(self.ids)

    def RowIdToOrdinal(self, gid):
        """Return the row ordinal given its id
        """
        if gid < 0:
            return gid
        else:
            ord = self.ids[gid]
            return ord

    def RowOrdinalToId(self, num):
        """Return the rowid for given its ordinal
        """
        if num >= 0:
            id = self.ordinals[num]
            return id
        else:
            return num

    def ReadRowAsDict(self, row, row_is_ordinal = 0):
        """Return a dictionary which contains all the fields.
        """
        if row_is_ordinal == 0:
            rowId = self.RowIdToOrdinal(row)
        else:
            rowId = row
        result = {}
        for i in range(self.NumColumns()):
            result[self.Column(i).name] = self.content[rowId][i]
        return result

    def ReadValue(self, row, col, row_is_ordinal = 0):
        """Return the requested value.
        """
        if row_is_ordinal == 0:
            rowId = self.RowIdToOrdinal(row)
        else:
            rowId = row
        colIndex = self.column_map[col].index
        return self.content[rowId][colIndex]

    def ValueRange(self, col):
        """Return the value range of the given column (given as string).
        """

        result = self.datasource.ExecuteSQL("SELECT min(%s), max(%s) FROM %s"
                %(col, col, self.layer.GetName()))
        result.ResetReading()
        feature = result.GetNextFeature()
        try:
            min = feature.GetField(0)
            max = feature.GetField(1)
        except:
            min = 0
            max = 0
        self.datasource.ReleaseResultSet(result)
        return (min, max)

    def UniqueValues(self, col):
        """Return all the values being found in the column (given as string).
        """
        result = self.datasource.ExecuteSQL((
                    "SELECT DISTINCT %s FROM %s ORDER BY %s"
                     %(col,self.layer.GetName(),col)))
        values = []
        while 1:
            feature = result.GetNextFeature()
            if feature is None:
                break
            values.append(feature.GetField(0))
        self.datasource.ReleaseResultSet(result)
        return values

    def SimpleQuery(self, left, comparison, right):
        """Return the FIDs resulting from the given query.
        """

        if comparison not in ("==", "!=", "<", "<=", ">=", ">"):
            raise ValueError("Comparison operator %r not allowed" %comparison)

        if comparison == "==":
            comparison = "="

        if isinstance(right, OGRColumn):
            right_template = right.name
        else:
            right_template = right

        if self.id_column is None:
            id = "FID"
        else:
            id = self.id_column
        query = ("SELECT %s FROM %s WHERE %s %s %s ORDER BY %s"
                % (id, self.tablename,left.name, comparison,
                   right_template, id))

        lay = self.datasource.ExecuteSQL(query)
        result = []
        while lay is not None:
            feature = lay.GetNextFeature()
            if feature is None:
                break
            result.append(feature.GetField(0))
        if lay is not None:
            self.datasource.ReleaseResultSet(lay)
        return result

    def Id_column(self):
        """Return the id_column.
        """
        return self.id_column


class OGRColumn:
    """Column description for a table for an ogr file
    """

    def __init__(self, name, type, index):
        self.name = name
        self.type = type
        self.index = index
1	# Copyright (C) 2004 by Intevation GmbH
2	# Authors:
3	# Nina Hueffmeyer <[email protected]>
4	#
5	# This program is free software under the GPL (>=v2)
6	# Read the file COPYING coming with the software for details.
7
8	__version__ = "$Revision$"
9	# $Source$
10	# $Id$
11
12	from __future__ import generators
13
14	try:
15	import ogr
16	except ImportError:
17	ogr = None
18
19	import os
20
21	from Thuban import _
22	from Thuban.Model import table
23	from Thuban.Model import transientdb
24	from Thuban.Model.transientdb import TransientDatabase
25
26	from Thuban.Model.data import SHAPETYPE_POLYGON, SHAPETYPE_ARC, SHAPETYPE_POINT
27	from Thuban.Model.data import RAW_PYTHON, RAW_SHAPEFILE, RAW_WKT
28
29	def has_ogr_support():
30	"""Return whether this Thuban instance supports ogr file formats
31
32	Having OGR support means that the ogr module can be
33	imported.
34	"""
35	return ogr is not None
36
37	if ogr is not None:
38	SHAPETYPE_UNKNOWN = ogr.wkbUnknown
39	SHAPETYPE_GEOMCOLL = ogr.wkbGeometryCollection
40	SHAPETYPE_NONE = ogr.wkbNone
41
42	# mapping from ogr-lib shapetypes and table constants to our constants
43	ogrlib_shapetypes = {ogr.wkbPolygon: SHAPETYPE_POLYGON,
44	ogr.wkbLineString: SHAPETYPE_ARC,
45	ogr.wkbPoint: SHAPETYPE_POINT,
46	ogr.wkbUnknown: SHAPETYPE_UNKNOWN,
47	ogr.wkbNone: SHAPETYPE_NONE,
48	ogr.wkbGeometryCollection: SHAPETYPE_GEOMCOLL}
49
50	fieldtype_map = {ogr.OFTString: table.FIELDTYPE_STRING,
51	ogr.OFTInteger: table.FIELDTYPE_INT,
52	ogr.OFTReal: table.FIELDTYPE_DOUBLE}
53
54	else:
55	ogrlib_shapetypes = {}
56	fieldtype_map = {}
57	SHAPETYPE_UNKNOWN = 0
58	SHAPETYPE_GEOMCOLL = 7
59	SHAPETYPE_NONE = 100
60
61
62	class OGRShape:
63	"""Represent one shape of an OGRShapeStore
64	"""
65
66	def __init__(self, shapestore, shape):
67	"""Initialize the shape object.
68
69	shapestore should be an instance of OGRShapeStore,
70	shape should be an instance of an OGRFeature.
71	"""
72	self.ogrlayer = shapestore.ogrlayer
73	id_column = shapestore.Id_column()
74	self.feature = shape
75	if id_column is None:
76	self.shapeid = self.feature.GetFID()
77	else:
78	self.shapeid = self.feature.GetField(id_column)
79	self.geom = self.feature.GetGeometryRef()
80	if self.geom:
81	self.shapetype = self.geom.GetGeometryType()
82	self.bbox = self._compute_bbox()
83	self.points = self._points()
84	else:
85	self.shapetype = ogr.wkbNone
86	self.bbox = None
87	self.points = [[]]
88	try:
89	self.shapetype = ogrlib_shapetypes[self.shapetype]
90	except:
91	self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]
92
93	self.geoms = self._geoms()
94
95	def _geoms(self):
96	"""Return a list of geometry objects.
97
98	If the shape is a geometry collection, all contained geometry
99	objects are stored to the list as OGRGeometry objects.
100	"""
101	geoms = []
102	if self.shapetype == SHAPETYPE_GEOMCOLL:
103	for i in range(self.geom.GetGeometryCount()):
104	geoms.append(OGRGeometry(self, self.geom, i))
105	return geoms
106
107	def _compute_bbox(self):
108	"""
109	Compute the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
110	"""
111	minx, maxx, miny, maxy = self.geom.GetEnvelope()
112	return (minx, miny, maxx, maxy)
113
114	def compute_bbox(self):
115	"""
116	Return the bounding box of the shape as a tuple (minx,miny,maxx,maxy)
117	"""
118	return self.bbox
119
120	def ShapeID(self):
121	"""Return the feature id of this shape.
122	"""
123	return self.shapeid
124
125	def Points(self):
126	"""Return the coordinates of the shape as a list of lists of pairs
127	"""
128	return self.points
129
130	def _points(self):
131	"""Get the coordinates of the shape as a list of lists of pairs
132	"""
133	shape = []
134
135	if self.geom is None:
136	return shape.append([])
137
138	# if geometry object is of type point or line
139	if self.geom.GetGeometryCount() == 0:
140	points =[]
141	for point in range(self.geom.GetPointCount()):
142	x = self.geom.GetX(point)
143	y = self.geom.GetY(point)
144	points.append((x, y))
145	return [points]
146	# if geometry object is of type polygon or multipolygon
147	for i in range(self.geom.GetGeometryCount()):
148	points = []
149	geometry = self.geom.GetGeometryRef(i)
150	# if geometry object is polygon
151	if geometry.GetGeometryCount() == 0:
152	for point in range(geometry.GetPointCount()):
153	x = geometry.GetX(point)
154	y = geometry.GetY(point)
155	points.append((x, y))
156	shape.append(points)
157	# if geometry object is of type multipolygon or geometry collection
158	else:
159	for j in range(geometry.GetGeometryCount()):
160	points = []
161	subgeom = geometry.GetGeometryRef(j)
162	for point in range(subgeom.GetPointCount()):
163	x = subgeom.GetX(point)
164	y = subgeom.GetY(point)
165	points.append((x, y))
166	shape.append(points)
167	return shape
168
169	def RawData(self):
170	"""Return the shape id to use with the shapestore
171	"""
172	return self.shapeid
173
174	def OGRLayer(self):
175	"""Return the ogrlayer object
176	"""
177	return self.ogrlayer
178
179	def ShapeType(self):
180	"""Return the shapetype of this shape (may differ from the layer's
181	shapetype)
182	"""
183	return self.shapetype
184
185	def GetGeoms(self):
186	"""Return the list of geometries of this feature.
187
188	If this feature is a geometry collection, all contained geometries
189	are given. Else the returned list is empty.
190	"""
191	return self.geoms
192
193	def GetGeom(self, index):
194	"""Return the OGRGeometry object at the specified index.
195
196	This is not none only if the shape is a geometry collection.
197	"""
198	if index < len(self.geoms):
199	return self.geoms[index]
200	else:
201	return None
202
203
204	class OGRGeometry:
205	"""This class represents a geometry belonging to a specified feature.
206	"""
207
208	def __init__(self, shape, geom, index):
209	"""Initialize the geometry object.
210
211	shape should be an OGRShape, which this geometry belongs to.
212	geom is the base geometry, index is the ReferenceID.
213	"""
214	self.shape = shape
215	self.index = index
216
217	self.geom = geom.GetGeometryRef(index)
218	try:
219	self.shapetype = ogrlib_shapetypes[self.geom.GetGeometryType()]
220	except:
221	self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]
222
223
224	def ShapeType(self):
225	"""Return the shapetype of this geometry object."""
226	return self.shapetype
227
228
229	class OGRShapeStore:
230	"""Corresponds to an OGRLayer object, containing features/shapes and
231	providing the same methods like ShapefileStore.
232	"""
233
234	def __init__(self, session, filename, layername, id_column = None):
235	"""Initialize the shapestore.
236
237	All required information is loaded from the datasource.
238	"""
239	# if id_column is None, data is loaded from file, so we need path
240	# if id_column is not None, data is loaded from database
241	if id_column is None:
242	self.filename = os.path.abspath(filename)
243	else:
244	self.filename = filename
245	self.layername = layername
246
247	self.ogrdatasource = ogr.Open(filename)
248	self.ogrlayer = (self.ogrdatasource).GetLayerByName(layername)
249
250	if id_column is not None:
251	self.id_column = id_column
252	else:
253	self.id_column = None
254
255	self.table = OGRTable(session, self.ogrdatasource, self.ogrlayer,
256	self.id_column)
257
258	self._open_ogrlayer(layername)
259
260	def _open_ogrlayer(self, layername):
261	"""Get all required information from the datasource.
262	"""
263	self.numshapes = self.ogrlayer.GetFeatureCount()
264	self.shapetype = self.ogrlayer.GetLayerDefn().GetGeomType()
265
266	extent = self.ogrlayer.GetExtent()
267	if extent:
268	self.bbox = [extent[0], extent[2], extent[1], extent[3]]
269	else:
270	self.bbox = None
271
272	try:
273	self.shapetype = ogrlib_shapetypes[self.shapetype]
274	except:
275	# if shapetype is not contained in ogrlib_shapetypes
276	# treat it like SHAPETYPE_UNKNOWN
277	self.shapetype = ogrlib_shapetypes[ogr.wkbUnknown]
278
279	self.shapes = self.shapes()
280
281	def shapes(self):
282	"""Return a collection of all features as OGRShape objects.
283	"""
284	shapes = {}
285	self.ogrlayer.ResetReading()
286	if self.id_column is None:
287	nextFeature = self.ogrlayer.GetNextFeature()
288	while nextFeature is not None:
289	fid = nextFeature.GetFID()
290	shape = OGRShape(self, nextFeature)
291	shapes[shape.ShapeID()] = shape
292	nextFeature = self.ogrlayer.GetNextFeature()
293	else:
294	lay = self.ogrdatasource.ExecuteSQL("SELECT %s, * from %s"
295	% (self.id_column, self.layername))
296	if lay is not None:
297	lay.ResetReading()
298	nextFeature = lay.GetNextFeature()
299	while nextFeature is not None:
300	fid = nextFeature.GetField(0)
301	shape = OGRShape(self, nextFeature)
302	shapes[shape.ShapeID()] = shape
303	nextFeature = lay.GetNextFeature()
304	self.ogrdatasource.ReleaseResultSet(lay)
305	return shapes
306
307	def OGRLayer(self):
308	"""Return the OGRLayer object
309	"""
310	return self.ogrlayer
311
312	def FileName(self):
313	"""Return the filename used to open the file
314	"""
315	return self.filename
316
317	def FileType(self):
318	"""Return the filetype. This is depending on the driver used to open
319	the file.
320	"""
321	return self.ogrdatasource.GetDriver().GetName()
322
323	def ShapeType(self):
324	"""Return the type of the shapes in the shapestore.
325
326	This is either SHAPETYPE_POINT, SHAPETYPE_ARC, SHAPETYPE_POLYGON,
327	SHAEPTYPE_GEOMCOLL, SHAPETYPE_NONE or SHAPETYPE_UNKNOWN.
328	"""
329	return self.shapetype
330
331	def RawShapeFormat(self):
332	"""Return the raw data format of the shape data, i.e. RAW_PYTHON
333	"""
334	return RAW_PYTHON
335
336	def NumShapes(self):
337	"""Return the number of shapes in the shape store
338	"""
339	return self.numshapes
340
341	def BoundingBox(self):
342	"""Return the bounding box of the shapes in the shapestore.
343	"""
344	return self.bbox
345
346	def ShapesInRegion(self, bbox):
347	"""Return an iterable over the shapes that overlap the bounding box.
348
349	The bbox parameter should be the bounding box as a tuple in the
350	form (minx, miny, maxx, maxy) in the coordinate system of the
351	shape store.
352	"""
353	left, bottom, right, top = bbox
354
355	# create a geometry which can be passed to the layer as spatial filter
356	bboxpolygon = ogr.CreateGeometryFromWkt(
357	('Polygon((%s %s, %s %s, %s %s,%s %s, %s %s))'
358	%(left, bottom, left, top, right, top,
359	right, bottom, left, bottom)))
360
361	if self.ogrlayer.GetSpatialRef():
362	bboxpolygon.AssignSpatialReference(self.ogrlayer.GetSpatialRef())
363
364	self.ogrlayer.ResetReading()
365	#ogrlayer.SetSpatialFilterRect(left, bottom, right, top)
366	self.ogrlayer.SetSpatialFilter(bboxpolygon)
367
368	numFeatures = self.ogrlayer.GetFeatureCount()
369	# if no features are in bbox, return all features as shapesInRegion
370	# (PostGIS sometimes returns no features even if they are within
371	# the bounding box)
372	if numFeatures == 0:
373	self.ogrlayer.SetSpatialFilter(None)
374	numFeatures = self.ogrlayer.GetFeatureCount()
375	for feature in range(numFeatures):
376	nextFeature = self.ogrlayer.GetNextFeature()
377	if self.id_column is None:
378	yield self.shapes[nextFeature.GetFID()]
379	else:
380	yield self.shapes[nextFeature.GetField(self.id_column)]
381
382	self.ogrlayer.SetSpatialFilter(None)
383	bboxpolygon.Destroy()
384
385	def AllShapes(self):
386	"""Return an iterable over the shapes in the shape store.
387	"""
388	for id in range(len(self.shapes)):
389	yield self.shapes[id]
390
391	def Shape(self, fid):
392	"""Return the shape with fid = fid
393	"""
394	if fid in self.table.ids.keys():
395	return self.shapes[fid]
396	else:
397	return None
398
399	def Table(self):
400	"""Return the table containing the attribute data
401	"""
402	return self.table
403
404	def Dependencies(self):
405	"""Return the empty tuple.
406	"""
407	return ()
408
409	def OrigShapeStore(self):
410	"""Return None."""
411	return None
412
413	def Id_column(self):
414	"""Return the id_column.
415	"""
416	return self.id_column
417
418	class OGRTable(transientdb.AutoTransientTable):
419	"""A Table for an ogr datasource.
420	"""
421
422	def __init__(self, session, ds, layer, id_column):
423	"""Initialize the OGRTable.
424
425	session - should be the current session.
426	ds - should be an instance of OGRDatasource.
427	layer - should be an instance of OGRLayer.
428	id_column - should be the name of the column used as ID column
429	"""
430	self.datasource = ds
431	self.layer = layer
432	self.tablename = self.layer.GetName()
433	self.id_column = id_column
434
435	# Map column names and indices to column objects.
436	self.column_map = {}
437
438	# Map feature ids to ordinals.
439	self._map_ords_and_ids()
440
441	self._fetch_table_information()
442	self._fetch_table_content()
443
444	transientdb.AutoTransientTable.__init__(self, session.TransientDB(),
445	self)
446
447	def _fetch_table_information(self):
448	"""Internal: Update information about the table
449	"""
450	self.columns = []
451
452	layerdefn = self.layer.GetLayerDefn()
453	# if FID column is of interest
454	#col = OGRColumn("FID", table.FIELDTYPE_INT, layerdefn.GetFieldCount())
455	#self.columns.append(col)
456	for i in range(layerdefn.GetFieldCount()):
457	fielddef = layerdefn.GetFieldDefn(i)
458	fieldname = fielddef.GetName()
459	fieldtype = fieldtype_map[fielddef.GetType()]
460	fieldindex = layerdefn.GetFieldIndex(fieldname)
461	col = OGRColumn(fieldname, fieldtype, fieldindex)
462	if col is not None:
463	self.columns.append(col)
464
465	for col in self.columns:
466	self.column_map[col.name] = col
467	self.column_map[col.index] = col
468
469	def _fetch_table_content(self):
470	"""Internal: Update information contained in the table
471	"""
472	self.content = []
473	layerdefn = self.layer.GetLayerDefn()
474
475	self.layer.ResetReading()
476	for i in range(self.layer.GetFeatureCount()):
477	nextFeature = self.layer.GetNextFeature()
478	row = []
479	for j in range(layerdefn.GetFieldCount()):
480	row.append(nextFeature.GetField(j))
481	# if FID should be listed in the table
482	#if self.id_column is None:
483	# row.append(nextFeature.GetFID())
484	#else:
485	# row.append(nextFeature.GetField(self.id_column))
486	self.content.append(row)
487
488	def _map_ords_and_ids(self):
489	"""Create collections which map ordinals to ids and verse visa.
490	"""
491	self.ordinals = {}
492	self.ids = {}
493
494	if self.id_column is not None:
495	lay = self.datasource.ExecuteSQL("SELECT %s from %s"
496	%(self.id_column, self.tablename))
497	lay.ResetReading()
498	nextFeature = lay.GetNextFeature()
499	else:
500	self.layer.ResetReading()
501	nextFeature = self.layer.GetNextFeature()
502
503	ord = 0
504	while nextFeature is not None:
505	if self.id_column is not None:
506	id = nextFeature.GetField(self.id_column)
507	nextFeature = lay.GetNextFeature()
508	else:
509	id = nextFeature.GetFID()
510	nextFeature = self.layer.GetNextFeature()
511	self.ordinals[ord] = id
512	self.ids[id] = ord
513	ord = ord + 1
514	if self.id_column is not None:
515	self.datasource.ReleaseResultSet(lay)
516
517	def TableName(self):
518	"""Return the name of the table, which is the name of the layer
519	"""
520	return self.tablename
521
522	def Title(self):
523	"""Return the title of the table.
524	"""
525	return self.tablename
526
527	def Dependencies(self):
528	"""Return an empty tuple.
529	"""
530	return ()
531
532	def NumColumns(self):
533	"""Return the number of columns.
534	"""
535	return len(self.columns)
536
537	def Columns(self):
538	"""Return all columns.
539	"""
540	return self.columns
541
542	def Column(self, col):
543	"""Return the column col. col can be either a string or an integer.
544	"""
545	return self.column_map[col]
546
547	def HasColumn(self, col):
548	"""Return if column col exists. col can be either a string or an
549	integer.
550	"""
551	return self.column_map.has_key(col)
552
553	def NumRows(self):
554	"""Return the number of rows in the table, which equals the number of
555	features in the layer.
556	"""
557	return len(self.ids)
558
559	def RowIdToOrdinal(self, gid):
560	"""Return the row ordinal given its id
561	"""
562	if gid < 0:
563	return gid
564	else:
565	ord = self.ids[gid]
566	return ord
567
568	def RowOrdinalToId(self, num):
569	"""Return the rowid for given its ordinal
570	"""
571	if num >= 0:
572	id = self.ordinals[num]
573	return id
574	else:
575	return num
576
577	def ReadRowAsDict(self, row, row_is_ordinal = 0):
578	"""Return a dictionary which contains all the fields.
579	"""
580	if row_is_ordinal == 0:
581	rowId = self.RowIdToOrdinal(row)
582	else:
583	rowId = row
584	result = {}
585	for i in range(self.NumColumns()):
586	result[self.Column(i).name] = self.content[rowId][i]
587	return result
588
589	def ReadValue(self, row, col, row_is_ordinal = 0):
590	"""Return the requested value.
591	"""
592	if row_is_ordinal == 0:
593	rowId = self.RowIdToOrdinal(row)
594	else:
595	rowId = row
596	colIndex = self.column_map[col].index
597	return self.content[rowId][colIndex]
598
599	def ValueRange(self, col):
600	"""Return the value range of the given column (given as string).
601	"""
602
603	result = self.datasource.ExecuteSQL("SELECT min(%s), max(%s) FROM %s"
604	%(col, col, self.layer.GetName()))
605	result.ResetReading()
606	feature = result.GetNextFeature()
607	try:
608	min = feature.GetField(0)
609	max = feature.GetField(1)
610	except:
611	min = 0
612	max = 0
613	self.datasource.ReleaseResultSet(result)
614	return (min, max)
615
616	def UniqueValues(self, col):
617	"""Return all the values being found in the column (given as string).
618	"""
619	result = self.datasource.ExecuteSQL((
620	"SELECT DISTINCT %s FROM %s ORDER BY %s"
621	%(col,self.layer.GetName(),col)))
622	values = []
623	while 1:
624	feature = result.GetNextFeature()
625	if feature is None:
626	break
627	values.append(feature.GetField(0))
628	self.datasource.ReleaseResultSet(result)
629	return values
630
631	def SimpleQuery(self, left, comparison, right):
632	"""Return the FIDs resulting from the given query.
633	"""
634
635	if comparison not in ("==", "!=", "<", "<=", ">=", ">"):
636	raise ValueError("Comparison operator %r not allowed" %comparison)
637
638	if comparison == "==":
639	comparison = "="
640
641	if isinstance(right, OGRColumn):
642	right_template = right.name
643	else:
644	right_template = right
645
646	if self.id_column is None:
647	id = "FID"
648	else:
649	id = self.id_column
650	query = ("SELECT %s FROM %s WHERE %s %s %s ORDER BY %s"
651	% (id, self.tablename,left.name, comparison,
652	right_template, id))
653
654	lay = self.datasource.ExecuteSQL(query)
655	result = []
656	while lay is not None:
657	feature = lay.GetNextFeature()
658	if feature is None:
659	break
660	result.append(feature.GetField(0))
661	if lay is not None:
662	self.datasource.ReleaseResultSet(lay)
663	return result
664
665	def Id_column(self):
666	"""Return the id_column.
667	"""
668	return self.id_column
669
670
671	class OGRColumn:
672	"""Column description for a table for an ogr file
673	"""
674
675	def __init__(self, name, type, index):
676	self.name = name
677	self.type = type
678	self.index = index
Name	Value
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