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 loadLayer(theLayerFile, DIR=TESTDATA):
"""Helper to load and return a single QGIS layer
Input
theLayerFile: Pathname to raster or vector file
DIR: Optional parameter stating the parent dir. If None,
pathname is assumed to be absolute
"""
# Extract basename and absolute path
myFileName = os.path.split(theLayerFile)[-1] # In case path was absolute
myBaseName, myExt = os.path.splitext(myFileName)
if DIR is None:
myPath = theLayerFile
else:
myPath = os.path.join(DIR, theLayerFile)
myKeywordPath = myPath[:-4] + '.keywords'
# Determine if layer is hazard or exposure
myKeywords = read_keywords(myKeywordPath)
myType = 'undefined'
if 'category' in myKeywords:
myType = myKeywords['category']
msg = 'Could not read %s' % myKeywordPath
assert myKeywords is not None, msg
# Create QGis Layer Instance
if myExt in ['.asc', '.tif']:
myLayer = QgsRasterLayer(myPath, myBaseName)
elif myExt in ['.shp']:
myLayer = QgsVectorLayer(myPath, myBaseName, 'ogr')
else:
myMessage = 'File %s had illegal extension' % myPath
raise Exception(myMessage)
myMessage = 'Layer "%s" is not valid' % str(myLayer.source())
assert myLayer.isValid(), myMessage
return myLayer, myType
