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committedJul 10, 2018
[processing][needs-doc][FEATURE] Sample raster values to point
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ltr-3_40final-3_4_0
1 parent 2688a9d commit d1cedbc

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‎python/plugins/processing/algs/help/qgis.yaml

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@@ -423,6 +423,15 @@ qgis:rasterlayerhistogram: >
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qgis:rasterlayerstatistics: >
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This algorithm computes basic statistics from the values in a given band of the raster layer.
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qgis:rastersampling: >
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This algorithm creates a new vector layer with the same attributes of the input layer and the raster values corresponding on the point location.
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Many raster layers can be chosen at the same time.
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If the raster layer has more than one band, all the band values are sampled.
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WARNING: raster layer(s) must be in the same CRS of the source point layer.
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qgis:rasterize: >
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This algorithm rasterizes map canvas content.
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@@ -558,4 +567,3 @@ qgis:definecurrentprojection: >
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This algorithm sets an existing layer's projection to the provided CRS. Contrary to the "Assign projection" algorithm, it will not output a new layer.
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For shapefile datasets, the .prj and .qpj files will be overwritten - or created if missing - to match the provided CRS.
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‎python/plugins/processing/algs/qgis/QgisAlgorithmProvider.py

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@@ -113,6 +113,7 @@
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from .Rasterize import RasterizeAlgorithm
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from .RasterCalculator import RasterCalculator
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from .RasterLayerStatistics import RasterLayerStatistics
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from .RasterSampling import RasterSampling
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from .RectanglesOvalsDiamondsFixed import RectanglesOvalsDiamondsFixed
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from .RectanglesOvalsDiamondsVariable import RectanglesOvalsDiamondsVariable
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from .RegularPoints import RegularPoints
@@ -229,6 +230,7 @@ def getAlgs(self):
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RasterCalculator(),
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RasterizeAlgorithm(),
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RasterLayerStatistics(),
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RasterSampling(),
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RectanglesOvalsDiamondsFixed(),
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RectanglesOvalsDiamondsVariable(),
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RegularPoints(),

‎python/plugins/processing/algs/qgis/RasterSampling.py

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# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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RasterSampling.py
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-----------------------
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Date : July 2018
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Copyright : (C) 2018 by Matteo Ghetta
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Email : matteo dot ghetta at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = 'Matteo Ghetta'
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__date__ = 'July 2018'
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__copyright__ = '(C) 2018, Matteo Ghetta'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import os
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from qgis.PyQt.QtGui import QIcon
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import (QgsApplication,
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QgsField,
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QgsFeatureSink,
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QgsRaster,
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QgsProcessing,
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QgsProcessingParameterMultipleLayers,
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QgsFields,
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QgsProcessingUtils,
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QgsProcessingException,
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QgsProcessingParameterFeatureSource,
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QgsProcessingParameterFeatureSink)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class RasterSampling(QgisAlgorithm):
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INPUT = 'INPUT'
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RASTERCOPY = 'RASTERCOPY'
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OUTPUT = 'OUTPUT'
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def name(self):
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return 'rastersampling'
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def displayName(self):
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return self.tr('Sample Raster Values')
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def group(self):
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return self.tr('Raster analysis')
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def groupId(self):
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return 'rasteranalysis'
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.addParameter(
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QgsProcessingParameterFeatureSource(
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self.INPUT,
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self.tr('Input Point Layer'),
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[QgsProcessing.TypeVectorPoint]
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)
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)
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self.addParameter(
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QgsProcessingParameterMultipleLayers(
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self.RASTERCOPY,
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self.tr('Raster Layer to sample'),
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QgsProcessing.TypeRaster
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)
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)
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self.addParameter(
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QgsProcessingParameterFeatureSink(
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self.OUTPUT,
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self.tr('Sampled Points')
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)
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)
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def processAlgorithm(self, parameters, context, feedback):
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source = self.parameterAsSource(
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parameters,
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self.INPUT,
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context
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)
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sampled_rasters = self.parameterAsLayerList(
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parameters,
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self.RASTERCOPY,
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context
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)
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if source is None:
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raise QgsProcessingException(self.invalidSourceError(parameters, self.INPUT))
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source_fields = source.fields()
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raster_fields = QgsFields()
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# append field to vector as rasterName_bandCount
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for i in sampled_rasters:
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for b in range(i.bandCount()):
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raster_fields.append(QgsField(i.name() + str('_{}'.format(b+1)), QVariant.Double))
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# combine all the vector fields
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out_fields = QgsProcessingUtils.combineFields(source_fields, raster_fields)
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(sink, dest_id) = self.parameterAsSink(
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parameters,
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self.OUTPUT,
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context,
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out_fields,
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source.wkbType(),
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source.sourceCrs()
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)
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if sink is None:
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raise QgsProcessingException(self.invalidSinkError(parameters, self.OUTPUT))
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total = 100.0 / source.featureCount() if source.featureCount() else 0
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features = source.getFeatures()
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for n, i in enumerate(source.getFeatures()):
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for rr in sampled_rasters:
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attrs = i.attributes()
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if rr.bandCount() >1:
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for b in range(rr.bandCount()):
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attrs.append(rr.dataProvider().identify(i.geometry().asPoint(),
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QgsRaster.IdentifyFormatValue).results()[b+1])
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attrs.append(rr.dataProvider().identify(i.geometry().asPoint(), QgsRaster.IdentifyFormatValue).results()[1])
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i.setAttributes(attrs)
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sink.addFeature(i, QgsFeatureSink.FastInsert)
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feedback.setProgress(int(n * total))
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return {self.OUTPUT: dest_id}

‎python/plugins/processing/tests/testdata/expected/raster_sampling.gml

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<?xml version="1.0" encoding="utf-8" ?>
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<ogr:FeatureCollection
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://ogr.maptools.org/ raster_sampling.xsd"
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xmlns:ogr="http://ogr.maptools.org/"
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xmlns:gml="http://www.opengis.net/gml">
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<gml:boundedBy>
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<gml:Box>
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<gml:coord><gml:X>18.67356158120081</gml:X><gml:Y>45.78707029401009</gml:Y></gml:coord>
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<gml:coord><gml:X>18.6923582796333</gml:X><gml:Y>45.80603482010714</gml:Y></gml:coord>
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</gml:Box>
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</gml:boundedBy>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.0">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6735615812008,45.8060348201071</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>1</ogr:id>
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<ogr:dem_1>91.9273986816406</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.1">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6891695540064,45.8035174051385</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>2</ogr:id>
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<ogr:dem_1>122.21053314209</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.2">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6923582796333,45.7875737770038</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>3</ogr:id>
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<ogr:dem_1>129.417877197266</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.3">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6796033771255,45.7870702940101</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>4</ogr:id>
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<ogr:dem_1>109.654373168945</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.4">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6812816537713,45.7964686432263</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>5</ogr:id>
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<ogr:dem_1>174.289291381836</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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<gml:featureMember>
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<ogr:raster_sampling fid="raster_sampling.5">
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<ogr:geometryProperty><gml:Point srsName="EPSG:4326"><gml:coordinates>18.6735615812008,45.7926086069411</gml:coordinates></gml:Point></ogr:geometryProperty>
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<ogr:id>6</ogr:id>
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<ogr:dem_1>93.1188354492188</ogr:dem_1>
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</ogr:raster_sampling>
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</gml:featureMember>
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</ogr:FeatureCollection>

‎python/plugins/processing/tests/testdata/expected/raster_sampling.xsd

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<?xml version="1.0" encoding="UTF-8"?>
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<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
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<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
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<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
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<xs:complexType name="FeatureCollectionType">
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<xs:complexContent>
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<xs:extension base="gml:AbstractFeatureCollectionType">
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<xs:attribute name="lockId" type="xs:string" use="optional"/>
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<xs:attribute name="scope" type="xs:string" use="optional"/>
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</xs:extension>
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</xs:complexContent>
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</xs:complexType>
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<xs:element name="raster_sampling" type="ogr:raster_sampling_Type" substitutionGroup="gml:_Feature"/>
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<xs:complexType name="raster_sampling_Type">
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<xs:complexContent>
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<xs:extension base="gml:AbstractFeatureType">
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<xs:sequence>
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<xs:element name="geometryProperty" type="gml:PointPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
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<xs:element name="id" nillable="true" minOccurs="0" maxOccurs="1">
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<xs:simpleType>
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<xs:restriction base="xs:long">
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<xs:totalDigits value="10"/>
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</xs:restriction>
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</xs:simpleType>
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</xs:element>
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<xs:element name="dem_1" nillable="true" minOccurs="0" maxOccurs="1">
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<xs:simpleType>
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<xs:restriction base="xs:decimal">
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</xs:restriction>
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</xs:simpleType>
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</xs:element>
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</xs:sequence>
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</xs:extension>
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</xs:complexContent>
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</xs:complexType>
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</xs:schema>

‎python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

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name: expected/kmeans_polys.gml
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type: vector
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- algorithm: qgis:rastersampling
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name: Raster sampling, points single band
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params:
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INPUT:
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name: custom/points_over.shp
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type: vector
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RASTERCOPY:
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params:
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- name: dem.tif
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type: raster
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type: multi
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results:
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OUTPUT:
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name: expected/raster_sampling.gml
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type: vector
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# See ../README.md for a description of the file format

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