Merge pull request #7194 from wonder-sk/snap-geometries-alg

[FEATURE] Snap geometries algorithm
qgis · Sep 14, 2018 · 9bcd21f · 9bcd21f
2 parents 4ac834d + 2b55858
commit 9bcd21f
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Showing 11 changed files with 547 additions and 1 deletion.
diff --git a/python/analysis/analysis_auto.sip b/python/analysis/analysis_auto.sip
@@ -13,6 +13,7 @@
 %Include auto_generated/raster/qgsrastercalcnode.sip
 %Include auto_generated/raster/qgstotalcurvaturefilter.sip
 %Include auto_generated/vector/qgsgeometrysnapper.sip
+%Include auto_generated/vector/qgsgeometrysnappersinglesource.sip
 %Include auto_generated/vector/qgszonalstatistics.sip
 %Include auto_generated/interpolation/qgsinterpolator.sip
 %Include auto_generated/interpolation/qgsgridfilewriter.sip

diff --git a/python/analysis/auto_generated/vector/qgsgeometrysnappersinglesource.sip.in b/python/analysis/auto_generated/vector/qgsgeometrysnappersinglesource.sip.in
@@ -0,0 +1,52 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/analysis/vector/qgsgeometrysnappersinglesource.h                 *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsGeometrySnapperSingleSource
+{
+%Docstring
+
+Makes sure that any two vertices of the vector layer are at least at distance given by the threshold value.
+The algorithm moves nearby vertices to one location and adds vertices to segments that are passing around other
+vertices within the threshold. It does not remove any vertices. Also, it does not modify geometries unless
+needed (it does not snap coordinates to a grid).
+
+This algorithm comes handy when doing vector overlay operations such as intersection, union or difference
+to prevent possible topological errors caused by numerical errors if coordinates are very close to each other.
+
+After running the algorithm some previously valid geometries may become invalid and therefore it may be useful
+to run Fix geometries algorithm afterwards.
+
+.. note::
+
+   Originally ported from GRASS implementation of Vect_snap_lines_list()
+
+.. versionadded:: 3.4
+%End
+
+%TypeHeaderCode
+#include "qgsgeometrysnappersinglesource.h"
+%End
+  public:
+
+    static int run( const QgsFeatureSource &source, QgsFeatureSink &sink, double thresh, QgsFeedback *feedback );
+%Docstring
+Run the algorithm on given source and output results to the sink, using threshold value in the source's map units.
+Returns number of modified geometries.
+%End
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/analysis/vector/qgsgeometrysnappersinglesource.h                 *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
diff --git a/python/plugins/processing/algs/qgis/SnapGeometries.py b/python/plugins/processing/algs/qgis/SnapGeometries.py
@@ -26,6 +26,7 @@
 __revision__ = '$Format:%H$'
 
 from qgis.analysis import (QgsGeometrySnapper,
+                           QgsGeometrySnapperSingleSource,
                            QgsInternalGeometrySnapper)
 from qgis.core import (QgsFeatureSink,
                        QgsProcessing,
@@ -71,7 +72,8 @@ def initAlgorithm(self, config=None):
                       self.tr('Prefer closest point, don\'t insert new vertices'),
                       self.tr('Move end points only, prefer aligning nodes'),
                       self.tr('Move end points only, prefer closest point'),
-                      self.tr('Snap end points to end points only')]
+                      self.tr('Snap end points to end points only'),
+                      self.tr('Snap to anchor nodes (single layer only)')]
         self.addParameter(QgsProcessingParameterEnum(
             self.BEHAVIOR,
             self.tr('Behavior'),
@@ -106,6 +108,9 @@ def processAlgorithm(self, parameters, context, feedback):
         total = 100.0 / source.featureCount() if source.featureCount() else 0
 
         if parameters[self.INPUT] != parameters[self.REFERENCE_LAYER]:
+            if mode == 7:
+                raise QgsProcessingException(self.tr('This mode applies when the input and reference layer are the same.'))
+
             snapper = QgsGeometrySnapper(reference_source)
             processed = 0
             for f in features:
@@ -119,6 +124,10 @@ def processAlgorithm(self, parameters, context, feedback):
                     sink.addFeature(f)
                 processed += 1
                 feedback.setProgress(processed * total)
+        elif mode == 7:
+            # input layer == ref layer
+            modified_count = QgsGeometrySnapperSingleSource.run(source, sink, tolerance, feedback)
+            feedback.pushInfo(self.tr('Snapped {} geometries.').format(modified_count))
         else:
             # snapping internally
             snapper = QgsInternalGeometrySnapper(tolerance, mode)

diff --git a/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg b/python/plugins/processing/tests/testdata/custom/circular_strings.gpkg
diff --git a/python/plugins/processing/tests/testdata/custom/snap_geometries.geojson b/python/plugins/processing/tests/testdata/custom/snap_geometries.geojson
@@ -0,0 +1,9 @@
+{
+"type": "FeatureCollection",
+"name": "snap_geometries",
+"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:EPSG::3857" } },
+"features": [
+{ "type": "Feature", "properties": { }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 20.123, 10.123 ], [ 20.123, 20.456 ], [ 20.2, 20.456 ], [ 20.2, 20.5 ], [ 30.0, 20.5 ], [ 30.0, 10.123 ], [ 29.8, 10.123 ], [ 21.0, 10.123 ], [ 20.123, 10.123 ] ] ] } },
+{ "type": "Feature", "properties": { }, "geometry": { "type": "Polygon", "coordinates": [ [ [ 31.0, 10.0 ], [ 20.0, 10.0 ], [ 20.0, 5.0 ], [ 31.0, 10.0 ] ] ] } }
+]
+}
diff --git a/python/plugins/processing/tests/testdata/expected/snap_geometries.gml b/python/plugins/processing/tests/testdata/expected/snap_geometries.gml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ snap_geometries.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>20</gml:X><gml:Y>5</gml:Y></gml:coord>
+      <gml:coord><gml:X>31</gml:X><gml:Y>20.5</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+
+  <gml:featureMember>
+    <ogr:snap_geometries fid="snap_geometries.0">
+      <ogr:geometryProperty><gml:Polygon srsName="EPSG:3857"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>20.123,10.123 20.123,20.456 20.123,20.456 20.123,20.456 30.0,20.5 30.0,10.123 30.0,10.123 21.0,10.123 20.123,10.123</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty>
+    </ogr:snap_geometries>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:snap_geometries fid="snap_geometries.1">
+      <ogr:geometryProperty><gml:Polygon srsName="EPSG:3857"><gml:outerBoundaryIs><gml:LinearRing><gml:coordinates>31,10 30.0,10.123 21.0,10.123 20.123,10.123 20,5 31,10</gml:coordinates></gml:LinearRing></gml:outerBoundaryIs></gml:Polygon></ogr:geometryProperty>
+    </ogr:snap_geometries>
+  </gml:featureMember>
+</ogr:FeatureCollection>
diff --git a/python/plugins/processing/tests/testdata/expected/snap_geometries.xsd b/python/plugins/processing/tests/testdata/expected/snap_geometries.xsd
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="snap_geometries" type="ogr:snap_geometries_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="snap_geometries_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:PolygonPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>
diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -2045,6 +2045,22 @@ tests:
         name: expected/snap_internal.gml
         type: vector
 
+  - algorithm: qgis:snapgeometries
+    name: Test Snap Geometries (to each other)
+    params:
+      BEHAVIOR: '7'
+      INPUT:
+        name: custom/snap_geometries.geojson
+        type: vector
+      REFERENCE_LAYER:
+        name: custom/snap_geometries.geojson
+        type: vector
+      TOLERANCE: 0.5
+    results:
+      OUTPUT:
+        name: expected/snap_geometries.gml
+        type: vector
+
   - algorithm: qgis:poleofinaccessibility
     name: Pole of inaccessibility (polygons)
     params:

diff --git a/src/analysis/CMakeLists.txt b/src/analysis/CMakeLists.txt
@@ -123,6 +123,7 @@ SET(QGIS_ANALYSIS_SRCS
   raster/qgsrastermatrix.cpp
   vector/mersenne-twister.cpp
   vector/qgsgeometrysnapper.cpp
+  vector/qgsgeometrysnappersinglesource.cpp
   vector/qgszonalstatistics.cpp
 
   network/qgsgraph.cpp
@@ -231,6 +232,7 @@ SET(QGIS_ANALYSIS_HDRS
 
   vector/mersenne-twister.h
   vector/qgsgeometrysnapper.h
+  vector/qgsgeometrysnappersinglesource.h
   vector/qgszonalstatistics.h
   vector/geometry_checker/qgsgeometrycheckerutils.h
   vector/geometry_checker/qgsfeaturepool.h