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 testWhich(self):
"""Test that the which command works as expected."""
myBinary = 'gdalwarp'
myPath = which(myBinary)
# Check we found at least one match
assert len(myPath) > 0
def testWhich(self):
"""Test that the which command works as expected."""
myBinary = 'gdalwarp'
myPath = which(myBinary)
# Check we found at least one match
assert len(myPath) > 0
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