[FEATURE][processing] New algorithm for translating (moving) points

Allows geometries to be shifted by a x/y displacement
qgis · Aug 14, 2016 · 0f268bf · 0f268bf
1 parent a064c0a
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diff --git a/python/plugins/processing/algs/help/qgis.yaml b/python/plugins/processing/algs/help/qgis.yaml
@@ -452,6 +452,9 @@ qgis:symmetricaldifference: >
 qgis:texttofloat: >
   This algorithm modifies the type of a given attribute in a vector layer, converting a text attribute containing numeric strings into a numeric attribute.
 
+qgis:translate: >
+  This algorithm moves the geometries within a layer, by offsetting them with a specified x and y displacement.
+
 qgis:union: >
   This algorithm creates a layer containing all the features from both input layers. In the case of polygon layers, separate features are created for overlapping and non-overlapping features. The attribute table of the union layer contains attribute values from the respective input layer for non-overlapping features, and attribute values from both input layers for overlapping features.
 

diff --git a/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py b/python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
@@ -152,6 +152,7 @@
 from .PointOnSurface import PointOnSurface
 from .OffsetLine import OffsetLine
 from .PolygonCentroids import PolygonCentroids
+from .Translate import Translate
 
 pluginPath = os.path.normpath(os.path.join(
     os.path.split(os.path.dirname(__file__))[0], os.pardir))
@@ -205,7 +206,8 @@ def __init__(self):
                         RectanglesOvalsDiamondsVariable(),
                         RectanglesOvalsDiamondsFixed(), MergeLines(),
                         BoundingBox(), Boundary(), PointOnSurface(),
-                        OffsetLine(), PolygonCentroids()
+                        OffsetLine(), PolygonCentroids(),
+                        Translate()
                         ]
 
         if hasMatplotlib:

diff --git a/python/plugins/processing/algs/qgis/Translate.py b/python/plugins/processing/algs/qgis/Translate.py
@@ -0,0 +1,94 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    Translate.py
+    --------------
+    Date                 : August 2016
+    Copyright            : (C) 2016 by Nyall Dawson
+    Email                : nyall dot dawson at gmail dot com
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+__author__ = 'Nyall Dawson'
+__date__ = 'August 2016'
+__copyright__ = '(C) 2016, Nyall Dawson'
+
+# This will get replaced with a git SHA1 when you do a git archive323
+
+__revision__ = '$Format:%H$'
+
+import os
+
+from qgis.core import QgsGeometry, QgsWkbTypes
+
+from qgis.PyQt.QtGui import QIcon
+
+from processing.core.GeoAlgorithm import GeoAlgorithm
+from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
+from processing.core.parameters import ParameterVector, ParameterSelection, ParameterNumber
+from processing.core.outputs import OutputVector
+from processing.tools import dataobjects, vector
+
+pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]
+
+
+class Translate(GeoAlgorithm):
+
+    INPUT_LAYER = 'INPUT_LAYER'
+    OUTPUT_LAYER = 'OUTPUT_LAYER'
+    DELTA_X = 'DELTA_X'
+    DELTA_Y = 'DELTA_Y'
+
+    def defineCharacteristics(self):
+        self.name, self.i18n_name = self.trAlgorithm('Translate geometry')
+        self.group, self.i18n_group = self.trAlgorithm('Vector geometry tools')
+
+        self.addParameter(ParameterVector(self.INPUT_LAYER,
+                                          self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_ANY]))
+        self.addParameter(ParameterNumber(self.DELTA_X,
+                                          self.tr('Offset distance (x-axis)'), default=1.0))
+        self.addParameter(ParameterNumber(self.DELTA_Y,
+                                          self.tr('Offset distance (y-axis)'), default=0.0))
+
+        self.addOutput(OutputVector(self.OUTPUT_LAYER, self.tr('Translated')))
+
+    def processAlgorithm(self, progress):
+        layer = dataobjects.getObjectFromUri(
+            self.getParameterValue(self.INPUT_LAYER))
+
+        writer = self.getOutputFromName(
+            self.OUTPUT_LAYER).getVectorWriter(
+                layer.fields().toList(),
+                layer.wkbType(),
+                layer.crs())
+
+        delta_x = self.getParameterValue(self.DELTA_X)
+        delta_y = self.getParameterValue(self.DELTA_Y)
+
+        features = vector.features(layer)
+        total = 100.0 / len(features)
+
+        for current, input_feature in enumerate(features):
+            output_feature = input_feature
+            input_geometry = input_feature.geometry()
+            if input_geometry:
+                output_geometry = input_geometry
+                output_geometry.translate(delta_x, delta_y)
+                if not output_geometry:
+                    raise GeoAlgorithmExecutionException(
+                        self.tr('Error translating geometry'))
+
+                output_feature.setGeometry(output_geometry)
+
+            writer.addFeature(output_feature)
+            progress.setPercentage(int(current * total))
+
+        del writer
diff --git a/python/plugins/processing/tests/testdata/expected/lines_translated.gfs b/python/plugins/processing/tests/testdata/expected/lines_translated.gfs
@@ -0,0 +1,15 @@
+<GMLFeatureClassList>
+  <GMLFeatureClass>
+    <Name>lines_translated</Name>
+    <ElementPath>lines_translated</ElementPath>
+    <GeometryType>2</GeometryType>
+    <SRSName>EPSG:4326</SRSName>
+    <DatasetSpecificInfo>
+      <FeatureCount>7</FeatureCount>
+      <ExtentXMin>-0.90000</ExtentXMin>
+      <ExtentXMax>11.10000</ExtentXMax>
+      <ExtentYMin>-3.20000</ExtentYMin>
+      <ExtentYMax>4.80000</ExtentYMax>
+    </DatasetSpecificInfo>
+  </GMLFeatureClass>
+</GMLFeatureClassList>
diff --git a/python/plugins/processing/tests/testdata/expected/lines_translated.gml b/python/plugins/processing/tests/testdata/expected/lines_translated.gml
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation=""
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>-0.9</gml:X><gml:Y>-3.2</gml:Y></gml:coord>
+      <gml:coord><gml:X>11.1</gml:X><gml:Y>4.8</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6.1,1.8 9.1,1.8 9.1,2.8 11.1,4.8</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>-0.9,-1.2 1.1,-1.2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>2.1,-0.2 2.1,1.8 3.1,1.8 3.1,2.8</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>3.1,0.8 5.1,0.8</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>7.1,-3.2 10.1,-3.2</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>6.1,-3.2 10.1,0.8</gml:coordinates></gml:LineString></ogr:geometryProperty>
+    </ogr:lines_translated>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:lines_translated fid="lines.6">
+    </ogr:lines_translated>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -809,3 +809,15 @@ tests:
         name: expected/centroid_polys.gml
         type: vector
 
+  - algorithm: qgis:translategeometry
+    name: Lines translated
+    params:
+      DELTA_X: 0.1
+      DELTA_Y: -0.2
+      INPUT_LAYER:
+        name: lines.gml
+        type: vector
+    results:
+      OUTPUT_LAYER:
+        name: expected/lines_translated.gml
+        type: vector