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[processing] Fixes for field calculator and field mapper

- respect project distance, area and ellipsoid settings
- ensure expression variables are correctly evaluated

(cherry-picked from d32c41a)
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nyalldawson committed Mar 1, 2016
1 parent 2b72350 commit 3ea7860886629b4b041adcb1cb999186bdda451d
@@ -26,7 +26,7 @@
__revision__ = '$Format:%H$'

from PyQt4.QtCore import QVariant
from qgis.core import QgsExpression, QgsFeature, QgsField, QgsDistanceArea, QgsProject, GEO_NONE
from qgis.core import QgsExpression, QgsExpressionContext, QgsExpressionContextUtils, QgsFeature, QgsField, QgsDistanceArea, QgsProject, GEO_NONE
from qgis.utils import iface
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
@@ -111,8 +111,15 @@ def processAlgorithm(self, progress):
da.setEllipsoid(QgsProject.instance().readEntry(
'Measure', '/Ellipsoid', GEO_NONE)[0])
exp.setGeomCalculator(da)
exp.setDistanceUnits(QgsProject.instance().distanceUnits())
exp.setAreaUnits(QgsProject.instance().areaUnits())

if not exp.prepare(layer.pendingFields()):
exp_context = QgsExpressionContext()
exp_context.appendScope(QgsExpressionContextUtils.globalScope())
exp_context.appendScope(QgsExpressionContextUtils.projectScope())
exp_context.appendScope(QgsExpressionContextUtils.layerScope(layer))

if not exp.prepare(exp_context):
raise GeoAlgorithmExecutionException(
self.tr('Evaluation error: %s' % exp.evalErrorString()))

@@ -129,8 +136,9 @@ def processAlgorithm(self, progress):
rownum = 1
for current, f in enumerate(features):
rownum = current + 1
exp.setCurrentRowNumber(rownum)
value = exp.evaluate(f)
exp_context.setFeature(f)
exp_context.lastScope().setVariable("row_number", rownum)
value = exp.evaluate(exp_context)
if exp.hasEvalError():
calculationSuccess = False
error = exp.evalErrorString()
@@ -26,7 +26,8 @@
__revision__ = '$Format:%H$'


from qgis.core import QgsField, QgsExpression, QgsFeature
from qgis.core import QgsField, QgsExpression, QgsExpressionContext, QgsExpressionContextUtils, QgsDistanceArea, QgsProject, QgsFeature, GEO_NONE
from qgis.utils import iface
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
@@ -68,19 +69,36 @@ def processAlgorithm(self, progress):
provider = layer.dataProvider()
fields = []
expressions = []

da = QgsDistanceArea()
da.setSourceCrs(layer.crs().srsid())
da.setEllipsoidalMode(
iface.mapCanvas().mapSettings().hasCrsTransformEnabled())
da.setEllipsoid(QgsProject.instance().readEntry(
'Measure', '/Ellipsoid', GEO_NONE)[0])

exp_context = QgsExpressionContext()
exp_context.appendScope(QgsExpressionContextUtils.globalScope())
exp_context.appendScope(QgsExpressionContextUtils.projectScope())
exp_context.appendScope(QgsExpressionContextUtils.layerScope(layer))

for field_def in mapping:
fields.append(QgsField(name=field_def['name'],
type=field_def['type'],
len=field_def['length'],
prec=field_def['precision']))

expression = QgsExpression(field_def['expression'])
expression.setGeomCalculator(da)
expression.setDistanceUnits(QgsProject.instance().distanceUnits())
expression.setAreaUnits(QgsProject.instance().areaUnits())

if expression.hasParserError():
raise GeoAlgorithmExecutionException(
self.tr(u'Parser error in expression "{}": {}')
.format(unicode(field_def['expression']),
unicode(expression.parserErrorString())))
expression.prepare(provider.fields())
expression.prepare(exp_context)
if expression.hasEvalError():
raise GeoAlgorithmExecutionException(
self.tr(u'Evaluation error in expression "{}": {}')
@@ -108,8 +126,9 @@ def processAlgorithm(self, progress):
for i in xrange(0, len(mapping)):
field_def = mapping[i]
expression = expressions[i]
expression.setCurrentRowNumber(rownum)
value = expression.evaluate(inFeat)
exp_context.setFeature(inFeat)
exp_context.lastScope().setVariable("row_number", rownum)
value = expression.evaluate(exp_context)
if expression.hasEvalError():
calculationSuccess = False
error = expression.evalErrorString()
@@ -31,6 +31,7 @@
from PyQt4 import uic
from PyQt4.QtCore import Qt, QSettings
from PyQt4.QtGui import QDialog, QFileDialog, QApplication, QCursor, QMessageBox
from qgis.core import QgsExpressionContext, QgsExpressionContextUtils
from qgis.gui import QgsEncodingFileDialog

from processing.core.ProcessingConfig import ProcessingConfig
@@ -95,6 +96,14 @@ def updateLayer(self):
self.builder.setLayer(self.layer)
self.builder.loadFieldNames()

exp_context = QgsExpressionContext()
exp_context.appendScope(QgsExpressionContextUtils.globalScope())
exp_context.appendScope(QgsExpressionContextUtils.projectScope())
exp_context.appendScope(QgsExpressionContextUtils.layerScope(self.layer))
exp_context.lastScope().setVariable("row_number", 1)
exp_context.setHighlightedVariables(["row_number"])
self.builder.setExpressionContext(exp_context)

self.populateFields()

def setupSpinboxes(self, index):

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