def getStyleInfo(theLayer):
"""Get styleinfo associated with a layer.
Args:
* theLayer - InaSAFE layer (raster or vector)
Returns:
A list of dictionaries containing styleinfo info for a layer.
Raises:
* StyleInfoNotFoundException if the style is not found.
* InvalidParameterException if the paramers are not correct.
"""
if not theLayer:
raise InvalidParameterException()
if not hasattr(theLayer, 'get_style_info'):
myMessage = tr('Argument "%s" was not a valid layer instance' %
theLayer)
raise StyleInfoNotFoundException(myMessage)
try:
myValue = theLayer.get_style_info()
except Exception, e:
myMessage = tr('Styleinfo retrieval failed for %s\n %s' %
(theLayer.get_filename(), str(e)))
raise StyleInfoNotFoundException(myMessage)
def readKeywordsFromLayer(theLayer, keyword):
"""Get metadata from the keywords file associated with a layer.
.. note:: Requires a inasafe layer instance as parameter.
.. seealso:: getKeywordFromPath
Args:
* theLayer - a InaSAFE layer (vector or raster)
* keyword - the metadata keyword to retrieve e.g. 'title'
Returns:
A string containing the retrieved value for the keyword.
Raises:
KeywordNotFoundException if the keyword is not recognised.
"""
myValue = None
if theLayer is None:
raise InvalidParameterException()
try:
myValue = theLayer.get_keywords(keyword)
except Exception, e:
myMessage = tr('Keyword retrieval failed for %s (%s) \n %s' %
(theLayer.get_filename(), keyword, str(e)))
raise KeywordNotFoundException(myMessage)
def readKeywordsFromFile(theLayerPath, theKeyword=None):
"""Get metadata from the keywords file associated with a local
file in the file system.
.. note:: Requires a str representing a file path instance
as parameter As opposed to readKeywordsFromLayer which
takes a inasafe file object as parameter.
.. seealso:: readKeywordsFromLayer
Args:
* theLayerPath - a string representing a path to a layer
(e.g. '/tmp/foo.shp', '/tmp/foo.tif')
* theKeyword - optional - the metadata keyword to retrieve e.g. 'title'
Returns:
A string containing the retrieved value for the keyword if
the keyword argument is specified, otherwise the
complete keywords dictionary is returned.
Raises:
KeywordNotFoundException if the keyword is not recognised.
"""
# check the source layer path is valid
if not os.path.isfile(theLayerPath):
myMessage = tr('Cannot get keywords from a non-existant file.'
'%s does not exist.' % theLayerPath)
raise InvalidParameterException(myMessage)
# check there really is a keywords file for this layer
myKeywordFilePath = os.path.splitext(theLayerPath)[0]
myKeywordFilePath += '.keywords'
if not os.path.isfile(myKeywordFilePath):
myMessage = tr('No keywords file found for %s' % theLayerPath)
raise InvalidParameterException(myMessage)
#now get the requested keyword using the inasafe library
myDictionary = None
try:
myDictionary = read_keywords(myKeywordFilePath)
except Exception, e:
myMessage = tr('Keyword retrieval failed for %s (%s) \n %s' %
(myKeywordFilePath, theKeyword, str(e)))
raise KeywordNotFoundException(myMessage)
def _clipRasterLayer(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.
Args:
* theLayer - a valid QGIS raster layer in EPSG:4326
* 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.
* 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.
Returns:
Path to the output clipped layer (placed in the
system temp dir).
Raises:
Exception 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 InvalidParameterException(myMessage)
if theLayer.type() != QgsMapLayer.RasterLayer:
myMessage = tr('Expected a raster layer but received a %s.' %
str(theLayer.type()))
raise InvalidParameterException(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 theLayer.srs().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.srs().toProj4()))
raise InvalidProjectionException(myMessage)
# We need to provide gdalwarp with a dataset for the clip
# because unline gdal_translate, it does not take projwin.
myClipKml = extentToKml(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.
if theCellSize is None:
myCommand = ('gdalwarp -q -t_srs EPSG:4326 -r near '
'-cutline %s -crop_to_cutline -of GTiff '
'"%s" "%s"' % (myClipKml, myWorkingLayer, myFilename))
else:
myCommand = (
'gdalwarp -q -t_srs EPSG:4326 -r near -tr %f %f '
'-cutline %s -crop_to_cutline -of GTiff '
'"%s" "%s"' %
(theCellSize, theCellSize, myClipKml, myWorkingLayer, myFilename))
myExecutablePrefix = ''
if sys.platform == 'darwin': # Mac OS X
# .. todo:: FIXME - softcode gdal version in this path
myExecutablePrefix = ('/Library/Frameworks/GDAL.framework/'
'Versions/1.9/Programs/')
myCommand = myExecutablePrefix + myCommand
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.copyKeywords(theLayer,
myFilename,
theExtraKeywords=theExtraKeywords)
return myFilename # Filename of created file
def _clipVectorLayer(theLayer,
theExtent,
theExtraKeywords=None,
explodeMultipart=True):
"""Clip a Hazard or Exposure layer to the
extents of the current view frame. The layer must be a
vector layer or an exception will be thrown.
The output layer will always be in WGS84/Geographic.
Args:
* theLayer - a valid QGIS vector layer in EPSG:4326
* 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.
* theExtraKeywords - any additional keywords over and above the
original keywords that should be associated with the cliplayer.
* explodeMultipart - a bool describing if to convert multipart
features into singleparts
Returns:
Path to the output clipped layer (placed in the
system temp dir).
Raises:
None
"""
if not theLayer or not theExtent:
myMessage = tr('Layer or Extent passed to clip is None.')
raise InvalidParameterException(myMessage)
if theLayer.type() != QgsMapLayer.VectorLayer:
myMessage = tr('Expected a vector layer but received a %s.' %
str(theLayer.type()))
raise InvalidParameterException(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, theLayer.crs())
myRect = QgsRectangle(theExtent[0], theExtent[1], theExtent[2],
theExtent[3])
myProjectedExtent = myXForm.transformBoundingBox(myRect)
# Get vector layer
myProvider = theLayer.dataProvider()
if myProvider is None:
myMessage = tr('Could not obtain data provider from '
'layer "%s"' % theLayer.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,
theLayer.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(theLayer.crs(), myGeoCrs)
# Retrieve every feature with its geometry and attributes
myFeature = QgsFeature()
myCount = 0
while myProvider.nextFeature(myFeature):
myGeometry = myFeature.geometry()
# Loop through the parts adding them to the output file
# we write out single part features unless explodeMultipart is False
if explodeMultipart:
myGeometryList = explodeMultiPartGeometry(myGeometry)
else:
myGeometryList = [myGeometry]
for myPart in myGeometryList:
myPart.transform(myXForm)
myFeature.setGeometry(myPart)
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.')
raise NoFeaturesInExtentException(myMessage)
myKeywordIO = KeywordIO()
myKeywordIO.copyKeywords(theLayer,
myFilename,
theExtraKeywords=theExtraKeywords)
return myFilename # Filename of created file