def clip_by_extent(layer, extent, callback=None):
"""Clip a raster using a bounding box using processing.
Issue https://github.com/inasafe/inasafe/issues/3183
:param layer: The layer to reproject.
:type layer: QgsRasterLayer
:param extent: The extent.
:type extent: QgsRectangle
:param callback: A function to all to indicate progress. The function
should accept params 'current' (int) and 'maximum' (int). Defaults to
None.
:type callback: function
:return: Reprojected memory layer.
:rtype: QgsRasterLayer
.. versionadded:: 4.0
"""
parameters = dict()
# noinspection PyBroadException
try:
output_layer_name = quick_clip_steps['output_layer_name']
processing_step = quick_clip_steps['step_name']
output_layer_name = output_layer_name % layer.keywords['layer_purpose']
output_raster = unique_filename(dir=temp_dir())
# We make one pixel size buffer on the extent to cover every pixels.
# See https://github.com/inasafe/inasafe/issues/3655
pixel_size_x = layer.rasterUnitsPerPixelX()
pixel_size_y = layer.rasterUnitsPerPixelY()
buffer_size = max(pixel_size_x, pixel_size_y)
extent = extent.buffer(buffer_size)
if is_raster_y_inverted(layer):
# The raster is Y inverted. We need to switch Y min and Y max.
bbox = [
str(extent.xMinimum()),
str(extent.xMaximum()),
str(extent.yMaximum()),
str(extent.yMinimum())
]
else:
# The raster is normal.
bbox = [
str(extent.xMinimum()),
str(extent.xMaximum()),
str(extent.yMinimum()),
str(extent.yMaximum())
]
# These values are all from the processing algorithm.
# https://github.com/qgis/QGIS/blob/master/python/plugins/processing/
# algs/gdal/ClipByExtent.py
# Please read the file to know these parameters.
parameters['INPUT'] = layer.source()
parameters['NO_DATA'] = ''
parameters['PROJWIN'] = ','.join(bbox)
parameters['RTYPE'] = 5
parameters['COMPRESS'] = 4
parameters['JPEGCOMPRESSION'] = 75
parameters['ZLEVEL'] = 6
parameters['PREDICTOR'] = 1
parameters['TILED'] = False
parameters['BIGTIFF'] = 0
parameters['TFW'] = False
parameters['EXTRA'] = ''
parameters['OUTPUT'] = output_raster
result = processing.runalg("gdalogr:cliprasterbyextent", parameters)
if result is None:
raise ProcessingInstallationError
clipped = QgsRasterLayer(result['OUTPUT'], output_layer_name)
# We transfer keywords to the output.
clipped.keywords = layer.keywords.copy()
clipped.keywords['title'] = output_layer_name
check_layer(clipped)
except Exception as e:
# This step clip_raster_by_extent was nice to speedup the analysis.
# As we got an exception because the layer is invalid, we are not going
# to stop the analysis. We will return the original raster layer.
# It will take more processing time until we clip the vector layer.
# Check https://github.com/inasafe/inasafe/issues/4026 why we got some
# exceptions with this step.
LOGGER.exception(parameters)
LOGGER.exception(
'Error from QGIS clip raster by extent. Please check the QGIS '
'logs too !')
LOGGER.info(
'Even if we got an exception, we are continuing the analysis. The '
'layer is not clip.')
LOGGER.exception(str(e))
LOGGER.exception(get_error_message(e).to_text())
clipped = layer
return clipped
def test_raster_y_inverted(self):
"""Test if we can detect an upside down raster."""
# We should have one test with an inverted raster but as it's not
# usual, I'm not going to spend time.
layer = load_test_raster_layer('gisv4', 'hazard', 'earthquake.asc')
self.assertFalse(is_raster_y_inverted(layer))
def clip_by_extent(layer, extent):
"""Clip a raster using a bounding box using processing.
Issue https://github.com/inasafe/inasafe/issues/3183
:param layer: The layer to clip.
:type layer: QgsRasterLayer
:param extent: The extent.
:type extent: QgsRectangle
:return: Clipped layer.
:rtype: QgsRasterLayer
.. versionadded:: 4.0
"""
parameters = dict()
# noinspection PyBroadException
try:
output_layer_name = quick_clip_steps['output_layer_name']
output_layer_name = output_layer_name % layer.keywords['layer_purpose']
output_raster = unique_filename(suffix='.tif', dir=temp_dir())
# We make one pixel size buffer on the extent to cover every pixels.
# See https://github.com/inasafe/inasafe/issues/3655
pixel_size_x = layer.rasterUnitsPerPixelX()
pixel_size_y = layer.rasterUnitsPerPixelY()
buffer_size = max(pixel_size_x, pixel_size_y)
extent = extent.buffered(buffer_size)
if is_raster_y_inverted(layer):
# The raster is Y inverted. We need to switch Y min and Y max.
bbox = [
str(extent.xMinimum()),
str(extent.xMaximum()),
str(extent.yMaximum()),
str(extent.yMinimum())
]
else:
# The raster is normal.
bbox = [
str(extent.xMinimum()),
str(extent.xMaximum()),
str(extent.yMinimum()),
str(extent.yMaximum())
]
# These values are all from the processing algorithm.
# https://github.com/qgis/QGIS/blob/master/python/plugins/processing/
# algs/gdal/ClipByExtent.py
# Please read the file to know these parameters.
parameters['INPUT'] = layer.source()
parameters['NO_DATA'] = ''
parameters['PROJWIN'] = ','.join(bbox)
parameters['DATA_TYPE'] = 5
parameters['COMPRESS'] = 4
parameters['JPEGCOMPRESSION'] = 75
parameters['ZLEVEL'] = 6
parameters['PREDICTOR'] = 1
parameters['TILED'] = False
parameters['BIGTIFF'] = 0
parameters['TFW'] = False
parameters['EXTRA'] = ''
parameters['OUTPUT'] = output_raster
initialize_processing()
feedback = create_processing_feedback()
context = create_processing_context(feedback=feedback)
result = processing.run(
"gdal:cliprasterbyextent",
parameters,
context=context)
if result is None:
raise ProcessingInstallationError
clipped = QgsRasterLayer(result['OUTPUT'], output_layer_name)
# We transfer keywords to the output.
clipped.keywords = layer.keywords.copy()
clipped.keywords['title'] = output_layer_name
check_layer(clipped)
except Exception as e:
# This step clip_raster_by_extent was nice to speedup the analysis.
# As we got an exception because the layer is invalid, we are not going
# to stop the analysis. We will return the original raster layer.
# It will take more processing time until we clip the vector layer.
# Check https://github.com/inasafe/inasafe/issues/4026 why we got some
# exceptions with this step.
LOGGER.exception(parameters)
LOGGER.exception(
'Error from QGIS clip raster by extent. Please check the QGIS '
'logs too !')
LOGGER.info(
'Even if we got an exception, we are continuing the analysis. The '
'layer was not clipped.')
LOGGER.exception(str(e))
LOGGER.exception(get_error_message(e).to_text())
clipped = layer
return clipped
def test_raster_y_inverted(self):
"""Test if we can detect an upside down raster."""
# We should have one test with an inverted raster but as it's not
# usual, I'm not going to spend time.
layer = load_test_raster_layer('gisv4', 'hazard', 'earthquake.asc')
self.assertFalse(is_raster_y_inverted(layer))
