void visitData( const IData& d ) override { QgsFeatureId id = d.getIdentifier(); QgsGeometry* geom = mLocator->mGeoms.value( id ); QgsPoint pt; int afterVertex; double sqrDist = geom->closestSegmentWithContext( mSrcPoint, pt, afterVertex, nullptr, POINT_LOC_EPSILON ); if ( sqrDist < 0 ) return; QgsPoint edgePoints[2]; edgePoints[0] = geom->vertexAt( afterVertex - 1 ); edgePoints[1] = geom->vertexAt( afterVertex ); QgsPointLocator::Match m( QgsPointLocator::Edge, mLocator->mLayer, id, sqrt( sqrDist ), pt, afterVertex - 1, edgePoints ); // in range queries the filter may reject some matches if ( mFilter && !mFilter->acceptMatch( m ) ) return; if ( !mBest.isValid() || m.distance() < mBest.distance() ) mBest = m; }
QgsPoint QgsGeometryAnalyzer::createPointOffset( double x, double y, double dist, const QgsGeometry& lineGeom ) const { QgsPoint p( x, y ); QgsPoint minDistPoint; int afterVertexNr; lineGeom.closestSegmentWithContext( p, minDistPoint, afterVertexNr ); int beforeVertexNr = afterVertexNr - 1; QgsPoint beforeVertex = lineGeom.vertexAt( beforeVertexNr ); QgsPoint afterVertex = lineGeom.vertexAt( afterVertexNr ); //get normal vector double dx = afterVertex.x() - beforeVertex.x(); double dy = afterVertex.y() - beforeVertex.y(); double normalX = -dy; double normalY = dx; double normalLength = sqrt( normalX * normalX + normalY * normalY ); normalX *= ( dist / normalLength ); normalY *= ( dist / normalLength ); double debugLength = sqrt( normalX * normalX + normalY * normalY ); //control Q_UNUSED( debugLength ); return QgsPoint( x - normalX, y - normalY ); //negative values -> left side, positive values -> right side }
int QgsTransectSample::createSample( QProgressDialog* pd ) { Q_UNUSED( pd ); if ( !mStrataLayer || !mStrataLayer->isValid() ) { return 1; } if ( !mBaselineLayer || !mBaselineLayer->isValid() ) { return 2; } //stratum id is not necessarily an integer QVariant::Type stratumIdType = QVariant::Int; if ( !mStrataIdAttribute.isEmpty() ) { stratumIdType = mStrataLayer->pendingFields().field( mStrataIdAttribute ).type(); } //create vector file writers for output QgsFields outputPointFields; outputPointFields.append( QgsField( "id", stratumIdType ) ); outputPointFields.append( QgsField( "station_id", QVariant::Int ) ); outputPointFields.append( QgsField( "stratum_id", stratumIdType ) ); outputPointFields.append( QgsField( "station_code", QVariant::String ) ); outputPointFields.append( QgsField( "start_lat", QVariant::Double ) ); outputPointFields.append( QgsField( "start_long", QVariant::Double ) ); QgsVectorFileWriter outputPointWriter( mOutputPointLayer, "utf-8", outputPointFields, QGis::WKBPoint, &( mStrataLayer->crs() ) ); if ( outputPointWriter.hasError() != QgsVectorFileWriter::NoError ) { return 3; } outputPointFields.append( QgsField( "bearing", QVariant::Double ) ); //add bearing attribute for lines QgsVectorFileWriter outputLineWriter( mOutputLineLayer, "utf-8", outputPointFields, QGis::WKBLineString, &( mStrataLayer->crs() ) ); if ( outputLineWriter.hasError() != QgsVectorFileWriter::NoError ) { return 4; } QgsFields usedBaselineFields; usedBaselineFields.append( QgsField( "stratum_id", stratumIdType ) ); usedBaselineFields.append( QgsField( "ok", QVariant::String ) ); QgsVectorFileWriter usedBaselineWriter( mUsedBaselineLayer, "utf-8", usedBaselineFields, QGis::WKBLineString, &( mStrataLayer->crs() ) ); if ( usedBaselineWriter.hasError() != QgsVectorFileWriter::NoError ) { return 5; } //debug: write clipped buffer bounds with stratum id to same directory as out_point QFileInfo outputPointInfo( mOutputPointLayer ); QString bufferClipLineOutput = outputPointInfo.absolutePath() + "/out_buffer_clip_line.shp"; QgsFields bufferClipLineFields; bufferClipLineFields.append( QgsField( "id", stratumIdType ) ); QgsVectorFileWriter bufferClipLineWriter( bufferClipLineOutput, "utf-8", bufferClipLineFields, QGis::WKBLineString, &( mStrataLayer->crs() ) ); //configure distanceArea depending on minDistance units and output CRS QgsDistanceArea distanceArea; distanceArea.setSourceCrs( mStrataLayer->crs().srsid() ); if ( mMinDistanceUnits == Meters ) { distanceArea.setEllipsoidalMode( true ); } else { distanceArea.setEllipsoidalMode( false ); } //possibility to transform output points to lat/long QgsCoordinateTransform toLatLongTransform( mStrataLayer->crs(), QgsCoordinateReferenceSystem( 4326, QgsCoordinateReferenceSystem::EpsgCrsId ) ); //init random number generator mt_srand( QTime::currentTime().msec() ); QgsFeatureRequest fr; fr.setSubsetOfAttributes( QStringList() << mStrataIdAttribute << mMinDistanceAttribute << mNPointsAttribute, mStrataLayer->pendingFields() ); QgsFeatureIterator strataIt = mStrataLayer->getFeatures( fr ); QgsFeature fet; int nTotalTransects = 0; int nFeatures = 0; if ( pd ) { pd->setMaximum( mStrataLayer->featureCount() ); } while ( strataIt.nextFeature( fet ) ) { if ( pd ) { pd->setValue( nFeatures ); } if ( pd && pd->wasCanceled() ) { break; } if ( !fet.constGeometry() ) { continue; } const QgsGeometry* strataGeom = fet.constGeometry(); //find baseline for strata QVariant strataId = fet.attribute( mStrataIdAttribute ); QgsGeometry* baselineGeom = findBaselineGeometry( strataId.isValid() ? strataId : -1 ); if ( !baselineGeom ) { continue; } double minDistance = fet.attribute( mMinDistanceAttribute ).toDouble(); double minDistanceLayerUnits = minDistance; //if minDistance is in meters and the data in degrees, we need to apply a rough conversion for the buffer distance double bufferDist = bufferDistance( minDistance ); if ( mMinDistanceUnits == Meters && mStrataLayer->crs().mapUnits() == QGis::DecimalDegrees ) { minDistanceLayerUnits = minDistance / 111319.9; } QgsGeometry* clippedBaseline = strataGeom->intersection( baselineGeom ); if ( !clippedBaseline || clippedBaseline->wkbType() == QGis::WKBUnknown ) { delete clippedBaseline; continue; } QgsGeometry* bufferLineClipped = clipBufferLine( strataGeom, clippedBaseline, bufferDist ); if ( !bufferLineClipped ) { delete clippedBaseline; continue; } //save clipped baseline to file QgsFeature blFeature; blFeature.setGeometry( *clippedBaseline ); blFeature.setAttribute( "stratum_id", strataId ); blFeature.setAttribute( "ok", "f" ); usedBaselineWriter.addFeature( blFeature ); //start loop to create random points along the baseline int nTransects = fet.attribute( mNPointsAttribute ).toInt(); int nCreatedTransects = 0; int nIterations = 0; int nMaxIterations = nTransects * 50; QgsSpatialIndex sIndex; //to check minimum distance QMap< QgsFeatureId, QgsGeometry* > lineFeatureMap; while ( nCreatedTransects < nTransects && nIterations < nMaxIterations ) { double randomPosition = (( double )mt_rand() / MD_RAND_MAX ) * clippedBaseline->length(); QgsGeometry* samplePoint = clippedBaseline->interpolate( randomPosition ); ++nIterations; if ( !samplePoint ) { continue; } QgsPoint sampleQgsPoint = samplePoint->asPoint(); QgsPoint latLongSamplePoint = toLatLongTransform.transform( sampleQgsPoint ); QgsFeature samplePointFeature; samplePointFeature.setGeometry( samplePoint ); samplePointFeature.setAttribute( "id", nTotalTransects + 1 ); samplePointFeature.setAttribute( "station_id", nCreatedTransects + 1 ); samplePointFeature.setAttribute( "stratum_id", strataId ); samplePointFeature.setAttribute( "station_code", strataId.toString() + "_" + QString::number( nCreatedTransects + 1 ) ); samplePointFeature.setAttribute( "start_lat", latLongSamplePoint.y() ); samplePointFeature.setAttribute( "start_long", latLongSamplePoint.x() ); //find closest point on clipped buffer line QgsPoint minDistPoint; int afterVertex; if ( bufferLineClipped->closestSegmentWithContext( sampleQgsPoint, minDistPoint, afterVertex ) < 0 ) { continue; } //bearing between sample point and min dist point (transect direction) double bearing = distanceArea.bearing( sampleQgsPoint, minDistPoint ) / M_PI * 180.0; QgsPolyline sampleLinePolyline; QgsPoint ptFarAway( sampleQgsPoint.x() + ( minDistPoint.x() - sampleQgsPoint.x() ) * 1000000, sampleQgsPoint.y() + ( minDistPoint.y() - sampleQgsPoint.y() ) * 1000000 ); QgsPolyline lineFarAway; lineFarAway << sampleQgsPoint << ptFarAway; QgsGeometry* lineFarAwayGeom = QgsGeometry::fromPolyline( lineFarAway ); QgsGeometry* lineClipStratum = lineFarAwayGeom->intersection( strataGeom ); if ( !lineClipStratum ) { delete lineFarAwayGeom; delete lineClipStratum; continue; } //cancel if distance between sample point and line is too large (line does not start at point if ( lineClipStratum->distance( *samplePoint ) > 0.000001 ) { delete lineFarAwayGeom; delete lineClipStratum; continue; } //if lineClipStratum is a multiline, take the part line closest to sampleQgsPoint if ( lineClipStratum->wkbType() == QGis::WKBMultiLineString || lineClipStratum->wkbType() == QGis::WKBMultiLineString25D ) { QgsGeometry* singleLine = closestMultilineElement( sampleQgsPoint, lineClipStratum ); if ( singleLine ) { delete lineClipStratum; lineClipStratum = singleLine; } } //cancel if length of lineClipStratum is too small double transectLength = distanceArea.measure( lineClipStratum ); if ( transectLength < mMinTransectLength ) { delete lineFarAwayGeom; delete lineClipStratum; continue; } //search closest existing profile. Cancel if dist < minDist if ( otherTransectWithinDistance( lineClipStratum, minDistanceLayerUnits, minDistance, sIndex, lineFeatureMap, distanceArea ) ) { delete lineFarAwayGeom; delete lineClipStratum; continue; } QgsFeatureId fid( nCreatedTransects ); QgsFeature sampleLineFeature( fid ); sampleLineFeature.setGeometry( lineClipStratum ); sampleLineFeature.setAttribute( "id", nTotalTransects + 1 ); sampleLineFeature.setAttribute( "station_id", nCreatedTransects + 1 ); sampleLineFeature.setAttribute( "stratum_id", strataId ); sampleLineFeature.setAttribute( "station_code", strataId.toString() + "_" + QString::number( nCreatedTransects + 1 ) ); sampleLineFeature.setAttribute( "start_lat", latLongSamplePoint.y() ); sampleLineFeature.setAttribute( "start_long", latLongSamplePoint.x() ); sampleLineFeature.setAttribute( "bearing", bearing ); outputLineWriter.addFeature( sampleLineFeature ); //add point to file writer here. //It can only be written if the corresponding transect has been as well outputPointWriter.addFeature( samplePointFeature ); sIndex.insertFeature( sampleLineFeature ); Q_NOWARN_DEPRECATED_PUSH lineFeatureMap.insert( fid, sampleLineFeature.geometryAndOwnership() ); Q_NOWARN_DEPRECATED_POP delete lineFarAwayGeom; ++nTotalTransects; ++nCreatedTransects; } delete clippedBaseline; QgsFeature bufferClipFeature; bufferClipFeature.setGeometry( bufferLineClipped ); bufferClipFeature.setAttribute( "id", strataId ); bufferClipLineWriter.addFeature( bufferClipFeature ); //delete bufferLineClipped; //delete all line geometries in spatial index QMap< QgsFeatureId, QgsGeometry* >::iterator featureMapIt = lineFeatureMap.begin(); for ( ; featureMapIt != lineFeatureMap.end(); ++featureMapIt ) { delete( featureMapIt.value() ); } lineFeatureMap.clear(); delete baselineGeom; ++nFeatures; } if ( pd ) { pd->setValue( mStrataLayer->featureCount() ); } return 0; }