def limitations():
"""Get InaSAFE limitations.
:return: All limitations on current InaSAFE.
:rtype: list
"""
# import tr here to avoid side effects with safe (see notes above in import
# section.
from safe_qgis.utilities.utilities import tr
limitation_list = list()
limitation_list.append(tr('InaSAFE is not a hazard modelling tool.'))
limitation_list.append(
tr('Polygon area analysis (such as land use) is not yet supported.'))
limitation_list.append(
tr('Population count data (raster) must be provided in WGS84 '
'geographic coordinates.'))
limitation_list.append(
tr('Population by administration boundary is not yet supported.'))
limitation_list.append(
tr('InaSAFE is a Free and Open Source Software (FOSS) project, '
'published under the GPL V3 license. As such you may freely '
'download, share and (if you like) modify the software.'))
return limitation_list
def limitations():
"""Get InaSAFE limitations.
:return: All limitations on current InaSAFE.
:rtype: list
"""
#import tr here to avoid side effects with safe (see notes above in import
#section.
from safe_qgis.utilities.utilities import tr
limitation_list = list()
limitation_list.append(tr('InaSAFE is not a hazard modelling tool.'))
limitation_list.append(
tr('Polygon area analysis (such as land use) is not yet supported.'))
limitation_list.append(
tr('Population count data (raster) must be provided in WGS84 '
'geographic coordinates.'))
limitation_list.append(
tr('Population by administration boundary is not yet supported.'))
limitation_list.append(
tr('InaSAFE is a Free and Open Source Software (FOSS) project, '
'published under the GPL V3 license. As such you may freely '
'download, share and (if you like) modify the software.'))
return limitation_list
def disclaimer():
"""Get a standard disclaimer.
:returns: Standard disclaimer string for InaSAFE.
:rtype: str
"""
# import tr here to avoid side effects with safe (see notes above in import
# section.
from safe_qgis.utilities.utilities import tr
text = tr('InaSAFE has been jointly developed by Indonesian '
'Government-BNPB, Australian Government-AIFDR and the World '
'Bank-GFDRR. These agencies and the individual software '
'developers of InaSAFE take no responsibility for the '
'correctness of outputs from InaSAFE or decisions derived as '
'a consequence.')
return text
def disclaimer():
"""Get a standard disclaimer.
:returns: Standard disclaimer string for InaSAFE.
:rtype: str
"""
#import tr here to avoid side effects with safe (see notes above in import
#section.
from safe_qgis.utilities.utilities import tr
text = tr(
'InaSAFE has been jointly developed by Indonesian '
'Government-BNPB, Australian Government-AIFDR and the World '
'Bank-GFDRR. These agencies and the individual software '
'developers of InaSAFE take no responsibility for the '
'correctness of outputs from InaSAFE or decisions derived as '
'a consequence.')
return text
def emit(self, record):
"""Try to log the message to QGIS if available, otherwise do nothing.
:param record: logging record containing whatever info needs to be
logged.
"""
try:
from qgis.core import QgsMessageLog
# Check logging.LogRecord properties for lots of other goodies
# like line number etc. you can get from the log message.
QgsMessageLog.logMessage(record.getMessage(), 'InaSAFE', 0)
#Make sure it doesn't crash if using Safe without QGIS
except ImportError:
pass
except MemoryError:
msg = tr('Due to memory limitations on this machine, InaSAFE can '
'not handle the full log')
print msg
QgsMessageLog.logMessage(msg, 'InaSAFE', 0)
def emit(self, record):
"""Try to log the message to QGIS if available, otherwise do nothing.
:param record: logging record containing whatever info needs to be
logged.
"""
try:
from qgis.core import QgsMessageLog
# Check logging.LogRecord properties for lots of other goodies
# like line number etc. you can get from the log message.
QgsMessageLog.logMessage(record.getMessage(), 'InaSAFE', 0)
#Make sure it doesn't crash if using Safe without QGIS
except ImportError:
pass
except MemoryError:
msg = tr('Due to memory limitations on this machine, InaSAFE can '
'not handle the full log')
print msg
QgsMessageLog.logMessage(msg, 'InaSAFE', 0)
def _clip_raster_layer(
layer, extent, cell_size=None, extra_keywords=None):
"""Clip a Hazard or Exposure raster layer to the extents provided.
The layer must be a raster layer or an exception will be thrown.
.. note:: The extent *must* be in EPSG:4326.
The output layer will always be in WGS84/Geographic.
:param layer: A valid QGIS raster layer in EPSG:4326
:type layer: QgsRasterLayer
:param extent: An array representing the exposure layer
extents in the form [xmin, ymin, xmax, ymax]. It is assumed
that the coordinates are in EPSG:4326 although currently
no checks are made to enforce this.
or:
A QgsGeometry of type polygon.
**Polygon clipping currently only supported for vector datasets.**
:type extent: list(float), QgsGeometry
:param cell_size: Cell size (in GeoCRS) which the layer should
be resampled to. If not provided for a raster layer (i.e.
theCellSize=None), the native raster cell size will be used.
:type cell_size: float
:returns: Output clipped layer (placed in the system temp dir).
:rtype: QgsRasterLayer
:raises: InvalidProjectionError - if input layer is a density
layer in projected coordinates. See issue #123.
"""
if not layer or not extent:
message = tr('Layer or Extent passed to clip is None.')
raise InvalidParameterError(message)
if layer.type() != QgsMapLayer.RasterLayer:
message = tr(
'Expected a raster layer but received a %s.' %
str(layer.type()))
raise InvalidParameterError(message)
working_layer = str(layer.source())
# Check for existence of keywords file
base, _ = os.path.splitext(working_layer)
keywords_path = base + '.keywords'
message = tr(
'Input file to be clipped "%s" does not have the '
'expected keywords file %s' % (
working_layer,
keywords_path
))
verify(os.path.isfile(keywords_path), message)
# Raise exception if layer is projected and refers to density (issue #123)
# FIXME (Ole): Need to deal with it - e.g. by automatically reprojecting
# the layer at this point and setting the native resolution accordingly
# in its keywords.
keywords = read_file_keywords(keywords_path)
if 'datatype' in keywords and keywords['datatype'] == 'density':
if str(layer.crs().authid()) != 'EPSG:4326':
# This layer is not WGS84 geographic
message = (
'Layer %s represents density but has spatial reference "%s". '
'Density layers must be given in WGS84 geographic coordinates, '
'so please reproject and try again. For more information, '
'see issue https://github.com/AIFDR/inasafe/issues/123' % (
working_layer,
layer.crs().toProj4()
))
raise InvalidProjectionError(message)
# We need to provide gdalwarp with a dataset for the clip
# because unline gdal_translate, it does not take projwin.
clip_kml = extent_to_kml(extent)
# Create a filename for the clipped, resampled and reprojected layer
handle, filename = tempfile.mkstemp('.tif', 'clip_', temp_dir())
os.close(handle)
os.remove(filename)
# If no cell size is specified, we need to run gdalwarp without
# specifying the output pixel size to ensure the raster dims
# remain consistent.
binary_list = which('gdalwarp')
LOGGER.debug('Path for gdalwarp: %s' % binary_list)
if len(binary_list) < 1:
raise CallGDALError(
tr('gdalwarp could not be found on your computer'))
# Use the first matching gdalwarp found
binary = binary_list[0]
if cell_size is None:
command = (
'"%s" -q -t_srs EPSG:4326 -r near -cutline %s -crop_to_cutline '
'-of GTiff "%s" "%s"' % (
binary,
clip_kml,
working_layer,
filename))
else:
command = (
'"%s" -q -t_srs EPSG:4326 -r near -tr %f %f -cutline %s '
'-crop_to_cutline -of GTiff "%s" "%s"' % (
binary,
cell_size,
cell_size,
clip_kml,
working_layer,
filename))
LOGGER.debug(command)
result = QProcess().execute(command)
# For QProcess exit codes see
# http://qt-project.org/doc/qt-4.8/qprocess.html#execute
if result == -2: # cannot be started
message_detail = tr('Process could not be started.')
message = tr(
'<p>Error while executing the following shell command:'
'</p><pre>%s</pre><p>Error message: %s'
% (command, message_detail))
raise CallGDALError(message)
elif result == -1: # process crashed
message_detail = tr('Process crashed.')
message = tr('<p>Error while executing the following shell command:</p>'
'<pre>%s</pre><p>Error message: %s' %
(command, message_detail))
raise CallGDALError(message)
# .. todo:: Check the result of the shell call is ok
keyword_io = KeywordIO()
keyword_io.copy_keywords(layer, filename, extra_keywords=extra_keywords)
base_name = '%s clipped' % layer.name()
layer = QgsRasterLayer(filename, base_name)
return layer
def _clip_vector_layer(
layer,
extent,
extra_keywords=None,
explode_flag=True,
hard_clip_flag=False,
explode_attribute=None):
"""Clip a Hazard or Exposure layer to the extents provided.
The layer must be a vector layer or an exception will be thrown.
The output layer will always be in WGS84/Geographic.
:param layer: A valid QGIS vector or raster layer
:type layer:
:param extent: Either an array representing the exposure layer extents
in the form [xmin, ymin, xmax, ymax]. It is assumed that the
coordinates are in EPSG:4326 although currently no checks are made to
enforce this.
or:
A QgsGeometry of type polygon.
**Polygon clipping is currently only supported for vector datasets.**
:type extent: list(float, float, float, float)
:param extra_keywords: Optional keywords dictionary to be added to
output layer.
:type extra_keywords: dict
:param explode_flag: A bool specifying whether multipart features
should be 'exploded' into singleparts.
**This parameter is ignored for raster layer clipping.**
:type explode_flag: bool
:param hard_clip_flag: A bool specifying whether line and polygon
features that extend beyond the extents should be clipped such that
they are reduced in size to the part of the geometry that intersects
the extent only. Default is False.
**This parameter is ignored for raster layer clipping.**
:type hard_clip_flag: bool
:param explode_attribute: A str specifying to which attribute #1,
#2 and so on will be added in case of explode_flag being true. The
attribute is modified only if there are at least 2 parts.
:type explode_attribute: str
:returns: Clipped layer (placed in the system temp dir). The output layer
will be reprojected to EPSG:4326 if needed.
:rtype: QgsVectorLayer
"""
if not layer or not extent:
myMessage = tr('Layer or Extent passed to clip is None.')
raise InvalidParameterError(myMessage)
if layer.type() != QgsMapLayer.VectorLayer:
myMessage = tr('Expected a vector layer but received a %s.' %
str(layer.type()))
raise InvalidParameterError(myMessage)
#myHandle, myFilename = tempfile.mkstemp('.sqlite', 'clip_',
# temp_dir())
myHandle, myFilename = tempfile.mkstemp('.shp', 'clip_',
temp_dir())
# Ensure the file is deleted before we try to write to it
# fixes windows specific issue where you get a message like this
# ERROR 1: c:\temp\inasafe\clip_jpxjnt.shp is not a directory.
# This is because mkstemp creates the file handle and leaves
# the file open.
os.close(myHandle)
os.remove(myFilename)
# Get the clip extents in the layer's native CRS
myGeoCrs = QgsCoordinateReferenceSystem()
myGeoCrs.createFromSrid(4326)
myXForm = QgsCoordinateTransform(myGeoCrs, layer.crs())
myAllowedClipTypes = [QGis.WKBPolygon, QGis.WKBPolygon25D]
if type(extent) is list:
myRect = QgsRectangle(
extent[0], extent[1],
extent[2], extent[3])
# noinspection PyCallByClass
myClipPolygon = QgsGeometry.fromRect(myRect)
elif (type(extent) is QgsGeometry and
extent.wkbType in myAllowedClipTypes):
myRect = extent.boundingBox().toRectF()
myClipPolygon = extent
else:
raise InvalidClipGeometryError(
tr(
'Clip geometry must be an extent or a single part'
'polygon based geometry.'))
myProjectedExtent = myXForm.transformBoundingBox(myRect)
# Get vector layer
myProvider = layer.dataProvider()
if myProvider is None:
myMessage = tr('Could not obtain data provider from '
'layer "%s"' % layer.source())
raise Exception(myMessage)
# Get the layer field list, select by our extent then write to disk
# .. todo:: FIXME - for different geometry types we should implement
# different clipping behaviour e.g. reject polygons that
# intersect the edge of the bbox. Tim
myRequest = QgsFeatureRequest()
if not myProjectedExtent.isEmpty():
myRequest.setFilterRect(myProjectedExtent)
myRequest.setFlags(QgsFeatureRequest.ExactIntersect)
myFieldList = myProvider.fields()
myWriter = QgsVectorFileWriter(
myFilename,
'UTF-8',
myFieldList,
layer.wkbType(),
myGeoCrs,
#'SQLite') # FIXME (Ole): This works but is far too slow
'ESRI Shapefile')
if myWriter.hasError() != QgsVectorFileWriter.NoError:
myMessage = tr('Error when creating shapefile: <br>Filename:'
'%s<br>Error: %s' %
(myFilename, myWriter.hasError()))
raise Exception(myMessage)
# Reverse the coordinate xform now so that we can convert
# geometries from layer crs to geocrs.
myXForm = QgsCoordinateTransform(layer.crs(), myGeoCrs)
# Retrieve every feature with its geometry and attributes
myCount = 0
myHasMultipart = False
for myFeature in myProvider.getFeatures(myRequest):
myGeometry = myFeature.geometry()
# Loop through the parts adding them to the output file
# we write out single part features unless explode_flag is False
if explode_flag:
myGeometryList = explode_multipart_geometry(myGeometry)
else:
myGeometryList = [myGeometry]
for myPartIndex, myPart in enumerate(myGeometryList):
myPart.transform(myXForm)
if hard_clip_flag:
# Remove any dangling bits so only intersecting area is
# kept.
myPart = clip_geometry(myClipPolygon, myPart)
if myPart is None:
continue
myFeature.setGeometry(myPart)
# There are multiple parts and we want to show it in the
# explode_attribute
if myPartIndex > 0 and explode_attribute is not None:
myHasMultipart = True
myWriter.addFeature(myFeature)
myCount += 1
del myWriter # Flush to disk
if myCount < 1:
myMessage = tr(
'No features fall within the clip extents. Try panning / zooming '
'to an area containing data and then try to run your analysis '
'again. If hazard and exposure data doesn\'t overlap at all, it '
'is not possible to do an analysis. Another possibility is that '
'the layers do overlap but because they may have different '
'spatial references, they appear to be disjointed. If this is the '
'case, try to turn on reproject on-the-fly in QGIS.')
raise NoFeaturesInExtentError(myMessage)
myKeywordIO = KeywordIO()
if extra_keywords is None:
extra_keywords = {}
extra_keywords['had multipart polygon'] = myHasMultipart
myKeywordIO.copy_keywords(
layer, myFilename, extra_keywords=extra_keywords)
myBaseName = '%s clipped' % layer.name()
myLayer = QgsVectorLayer(myFilename, myBaseName, 'ogr')
return myLayer
def _clip_raster_layer(
theLayer, theExtent, theCellSize=None, theExtraKeywords=None):
"""Clip a Hazard or Exposure raster layer to the extents provided.
The layer must be a raster layer or an exception will be thrown.
.. note:: The extent *must* be in EPSG:4326.
The output layer will always be in WGS84/Geographic.
:param theLayer: A valid QGIS raster layer in EPSG:4326
:type theLayer: QgsRasterLayer
:param theExtent: An array representing the exposure layer
extents in the form [xmin, ymin, xmax, ymax]. It is assumed
that the coordinates are in EPSG:4326 although currently
no checks are made to enforce this.
or:
A QgsGeometry of type polygon.
**Polygon clipping currently only supported for vector datasets.**
:type theExtent: list(float), QgsGeometry
:param theCellSize: Cell size (in GeoCRS) which the layer should
be resampled to. If not provided for a raster layer (i.e.
theCellSize=None), the native raster cell size will be used.
:type theCellSize: float
:returns: Output clipped layer (placed in the system temp dir).
:rtype: QgsRasterLayer
:raises: InvalidProjectionError - if input layer is a density
layer in projected coordinates. See issue #123.
"""
if not theLayer or not theExtent:
myMessage = tr('Layer or Extent passed to clip is None.')
raise InvalidParameterError(myMessage)
if theLayer.type() != QgsMapLayer.RasterLayer:
myMessage = tr(
'Expected a raster layer but received a %s.' %
str(theLayer.type()))
raise InvalidParameterError(myMessage)
myWorkingLayer = str(theLayer.source())
# Check for existence of keywords file
myKeywordsPath = myWorkingLayer[:-4] + '.keywords'
myMessage = tr(
'Input file to be clipped "%s" does not have the '
'expected keywords file %s' % (
myWorkingLayer, myKeywordsPath))
verify(os.path.isfile(myKeywordsPath), myMessage)
# Raise exception if layer is projected and refers to density (issue #123)
# FIXME (Ole): Need to deal with it - e.g. by automatically reprojecting
# the layer at this point and setting the native resolution accordingly
# in its keywords.
myKeywords = readKeywordsFromFile(myKeywordsPath)
if 'datatype' in myKeywords and myKeywords['datatype'] == 'density':
if str(theLayer.crs().authid()) != 'EPSG:4326':
# This layer is not WGS84 geographic
myMessage = ('Layer %s represents density but has spatial '
'reference "%s". Density layers must be given in '
'WGS84 geographic coordinates, so please reproject '
'and try again. For more information, see issue '
'https://github.com/AIFDR/inasafe/issues/123'
% (myWorkingLayer, theLayer.crs().toProj4()))
raise InvalidProjectionError(myMessage)
# We need to provide gdalwarp with a dataset for the clip
# because unline gdal_translate, it does not take projwin.
myClipKml = extent_to_kml(theExtent)
# Create a filename for the clipped, resampled and reprojected layer
myHandle, myFilename = tempfile.mkstemp('.tif', 'clip_',
temp_dir())
os.close(myHandle)
os.remove(myFilename)
# If no cell size is specified, we need to run gdalwarp without
# specifying the output pixel size to ensure the raster dims
# remain consistent.
myBinaryList = which('gdalwarp')
LOGGER.debug('Path for gdalwarp: %s' % myBinaryList)
if len(myBinaryList) < 1:
raise CallGDALError(
tr('gdalwarp could not be found on your computer'))
# Use the first matching gdalwarp found
myBinary = myBinaryList[0]
if theCellSize is None:
myCommand = ('%s -q -t_srs EPSG:4326 -r near '
'-cutline %s -crop_to_cutline -of GTiff '
'"%s" "%s"' % (myBinary,
myClipKml,
myWorkingLayer,
myFilename))
else:
myCommand = ('%s -q -t_srs EPSG:4326 -r near -tr %f %f '
'-cutline %s -crop_to_cutline -of GTiff '
'"%s" "%s"' % (myBinary,
theCellSize,
theCellSize,
myClipKml,
myWorkingLayer,
myFilename))
LOGGER.debug(myCommand)
myResult = QProcess().execute(myCommand)
# For QProcess exit codes see
# http://qt-project.org/doc/qt-4.8/qprocess.html#execute
if myResult == -2: # cannot be started
myMessageDetail = tr('Process could not be started.')
myMessage = tr(
'<p>Error while executing the following shell command:'
'</p><pre>%s</pre><p>Error message: %s'
% (myCommand, myMessageDetail))
raise CallGDALError(myMessage)
elif myResult == -1: # process crashed
myMessageDetail = tr('Process could not be started.')
myMessage = tr('<p>Error while executing the following shell command:'
'</p><pre>%s</pre><p>Error message: %s'
% (myCommand, myMessageDetail))
raise CallGDALError(myMessage)
# .. todo:: Check the result of the shell call is ok
myKeywordIO = KeywordIO()
myKeywordIO.copy_keywords(
theLayer, myFilename, extra_keywords=theExtraKeywords)
myBaseName = '%s clipped' % theLayer.name()
myLayer = QgsRasterLayer(myFilename, myBaseName)
return myLayer
def _clip_vector_layer(
layer,
extent,
extra_keywords=None,
explode_flag=True,
hard_clip_flag=False,
explode_attribute=None):
"""Clip a Hazard or Exposure layer to the extents provided.
The layer must be a vector layer or an exception will be thrown.
The output layer will always be in WGS84/Geographic.
:param layer: A valid QGIS vector or raster layer
:type layer:
:param extent: Either an array representing the exposure layer extents
in the form [xmin, ymin, xmax, ymax]. It is assumed that the
coordinates are in EPSG:4326 although currently no checks are made to
enforce this.
or:
A QgsGeometry of type polygon.
**Polygon clipping is currently only supported for vector datasets.**
:type extent: list(float, float, float, float)
:param extra_keywords: Optional keywords dictionary to be added to
output layer.
:type extra_keywords: dict
:param explode_flag: A bool specifying whether multipart features
should be 'exploded' into singleparts.
**This parameter is ignored for raster layer clipping.**
:type explode_flag: bool
:param hard_clip_flag: A bool specifying whether line and polygon
features that extend beyond the extents should be clipped such that
they are reduced in size to the part of the geometry that intersects
the extent only. Default is False.
**This parameter is ignored for raster layer clipping.**
:type hard_clip_flag: bool
:param explode_attribute: A str specifying to which attribute #1,
#2 and so on will be added in case of explode_flag being true. The
attribute is modified only if there are at least 2 parts.
:type explode_attribute: str
:returns: Clipped layer (placed in the system temp dir). The output layer
will be reprojected to EPSG:4326 if needed.
:rtype: QgsVectorLayer
"""
if not layer or not extent:
myMessage = tr('Layer or Extent passed to clip is None.')
raise InvalidParameterError(myMessage)
if layer.type() != QgsMapLayer.VectorLayer:
myMessage = tr('Expected a vector layer but received a %s.' %
str(layer.type()))
raise InvalidParameterError(myMessage)
#myHandle, myFilename = tempfile.mkstemp('.sqlite', 'clip_',
# temp_dir())
myHandle, myFilename = tempfile.mkstemp('.shp', 'clip_',
temp_dir())
# Ensure the file is deleted before we try to write to it
# fixes windows specific issue where you get a message like this
# ERROR 1: c:\temp\inasafe\clip_jpxjnt.shp is not a directory.
# This is because mkstemp creates the file handle and leaves
# the file open.
os.close(myHandle)
os.remove(myFilename)
# Get the clip extents in the layer's native CRS
myGeoCrs = QgsCoordinateReferenceSystem()
myGeoCrs.createFromId(4326, QgsCoordinateReferenceSystem.EpsgCrsId)
myXForm = QgsCoordinateTransform(myGeoCrs, layer.crs())
myAllowedClipTypes = [QGis.WKBPolygon, QGis.WKBPolygon25D]
if type(extent) is list:
myRect = QgsRectangle(
extent[0], extent[1],
extent[2], extent[3])
# noinspection PyCallByClass
myClipPolygon = QgsGeometry.fromRect(myRect)
elif (type(extent) is QgsGeometry and
extent.wkbType in myAllowedClipTypes):
myRect = extent.boundingBox().toRectF()
myClipPolygon = extent
else:
raise InvalidClipGeometryError(
tr(
'Clip geometry must be an extent or a single part'
'polygon based geometry.'))
myProjectedExtent = myXForm.transformBoundingBox(myRect)
# Get vector layer
myProvider = layer.dataProvider()
if myProvider is None:
myMessage = tr('Could not obtain data provider from '
'layer "%s"' % layer.source())
raise Exception(myMessage)
# Get the layer field list, select by our extent then write to disk
# .. todo:: FIXME - for different geometry types we should implement
# different clipping behaviour e.g. reject polygons that
# intersect the edge of the bbox. Tim
myAttributes = myProvider.attributeIndexes()
myFetchGeometryFlag = True
myUseIntersectFlag = True
myProvider.select(
myAttributes,
myProjectedExtent,
myFetchGeometryFlag,
myUseIntersectFlag)
myFieldList = myProvider.fields()
myWriter = QgsVectorFileWriter(
myFilename,
'UTF-8',
myFieldList,
layer.wkbType(),
myGeoCrs,
#'SQLite') # FIXME (Ole): This works but is far too slow
'ESRI Shapefile')
if myWriter.hasError() != QgsVectorFileWriter.NoError:
myMessage = tr('Error when creating shapefile: <br>Filename:'
'%s<br>Error: %s' %
(myFilename, myWriter.hasError()))
raise Exception(myMessage)
# Reverse the coordinate xform now so that we can convert
# geometries from layer crs to geocrs.
myXForm = QgsCoordinateTransform(layer.crs(), myGeoCrs)
# Retrieve every feature with its geometry and attributes
myFeature = QgsFeature()
myCount = 0
myHasMultipart = False
if explode_attribute is not None:
theExplodeAttributeIndex = myProvider.fieldNameIndex(
explode_attribute)
while myProvider.nextFeature(myFeature):
myGeometry = myFeature.geometry()
if explode_attribute is not None:
myAttrs = myFeature.attributeMap()
# Loop through the parts adding them to the output file
# we write out single part features unless explode_flag is False
if explode_flag:
myGeometryList = explode_multipart_geometry(myGeometry)
else:
myGeometryList = [myGeometry]
for myPartIndex, myPart in enumerate(myGeometryList):
myPart.transform(myXForm)
if hard_clip_flag:
# Remove any dangling bits so only intersecting area is
# kept.
myPart = clip_geometry(myClipPolygon, myPart)
if myPart is None:
continue
myFeature.setGeometry(myPart)
# There are multiple parts and we want to show it in the
# explode_attribute
if myPartIndex > 0 and explode_attribute is not None:
myHasMultipart = True
myPartAttr = QVariant(
'%s #%s' % (myAttrs[theExplodeAttributeIndex].toString(),
myPartIndex))
myFeature.changeAttribute(theExplodeAttributeIndex, myPartAttr)
myWriter.addFeature(myFeature)
myCount += 1
del myWriter # Flush to disk
if myCount < 1:
myMessage = tr(
'No features fall within the clip extents. Try panning / zooming '
'to an area containing data and then try to run your analysis '
'again. If hazard and exposure data doesn\'t overlap at all, it '
'is not possible to do an analysis. Another possibility is that '
'the layers do overlap but because they may have different '
'spatial references, they appear to be disjointed. If this is the '
'case, try to turn on reproject on-the-fly in QGIS.')
raise NoFeaturesInExtentError(myMessage)
myKeywordIO = KeywordIO()
if extra_keywords is None:
extra_keywords = {}
extra_keywords['HAD_MULTIPART_POLY'] = myHasMultipart
myKeywordIO.copy_keywords(
layer, myFilename, extra_keywords=extra_keywords)
myBaseName = '%s clipped' % layer.name()
myLayer = QgsVectorLayer(myFilename, myBaseName, 'ogr')
return myLayer
