QGIS API Documentation 3.37.0-Master (4ace69f83af)
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qgsmeshlayerprofilegenerator.cpp
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1/***************************************************************************
2 qgsmeshlayerprofilegenerator.cpp
3 ---------------
4 begin : March 2022
5 copyright : (C) 2022 by Nyall Dawson
6 email : nyall dot dawson at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
18#include "qgsprofilerequest.h"
19#include "qgscurve.h"
20#include "qgsmeshlayer.h"
22#include "qgsgeos.h"
23#include "qgsterrainprovider.h"
24#include "qgsmeshlayerutils.h"
25#include "qgslinesymbol.h"
26#include "qgsfillsymbol.h"
28#include "qgsprofilesnapping.h"
29#include "qgsprofilepoint.h"
30
31//
32// QgsMeshLayerProfileGenerator
33//
34
36{
37 return QStringLiteral( "mesh" );
38}
39
40QVector<QgsProfileIdentifyResults> QgsMeshLayerProfileResults::identify( const QgsProfilePoint &point, const QgsProfileIdentifyContext &context )
41{
42 const QVector<QgsProfileIdentifyResults> noLayerResults = QgsAbstractProfileSurfaceResults::identify( point, context );
43
44 // we have to make a new list, with the correct layer reference set
45 QVector<QgsProfileIdentifyResults> res;
46 res.reserve( noLayerResults.size() );
47 for ( const QgsProfileIdentifyResults &result : noLayerResults )
48 {
49 res.append( QgsProfileIdentifyResults( mLayer, result.results() ) );
50 }
51 return res;
52}
53
54//
55// QgsMeshLayerProfileGenerator
56//
57
60 , mId( layer->id() )
61 , mFeedback( std::make_unique< QgsFeedback >() )
62 , mProfileCurve( request.profileCurve() ? request.profileCurve()->clone() : nullptr )
63 , mSourceCrs( layer->crs() )
64 , mTargetCrs( request.crs() )
65 , mTransformContext( request.transformContext() )
66 , mOffset( layer->elevationProperties()->zOffset() )
67 , mScale( layer->elevationProperties()->zScale() )
68 , mLayer( layer )
69 , mStepDistance( request.stepDistance() )
70{
71 layer->updateTriangularMesh();
72 mTriangularMesh = *layer->triangularMesh();
73
74 mSymbology = qgis::down_cast< QgsMeshLayerElevationProperties * >( layer->elevationProperties() )->profileSymbology();
75 mElevationLimit = qgis::down_cast< QgsMeshLayerElevationProperties * >( layer->elevationProperties() )->elevationLimit();
76 mLineSymbol.reset( qgis::down_cast< QgsMeshLayerElevationProperties * >( layer->elevationProperties() )->profileLineSymbol()->clone() );
77 mFillSymbol.reset( qgis::down_cast< QgsMeshLayerElevationProperties * >( layer->elevationProperties() )->profileFillSymbol()->clone() );
78}
79
81{
82 return mId;
83}
84
86
88{
89 if ( !mProfileCurve || mFeedback->isCanceled() )
90 return false;
91
92 // we need to transform the profile curve to the mesh's CRS
93 QgsGeometry transformedCurve( mProfileCurve->clone() );
94 mLayerToTargetTransform = QgsCoordinateTransform( mSourceCrs, mTargetCrs, mTransformContext );
95
96 try
97 {
98 transformedCurve.transform( mLayerToTargetTransform, Qgis::TransformDirection::Reverse );
99 }
100 catch ( QgsCsException & )
101 {
102 QgsDebugError( QStringLiteral( "Error transforming profile line to mesh CRS" ) );
103 return false;
104 }
105
106 if ( mFeedback->isCanceled() )
107 return false;
108
109 mResults = std::make_unique< QgsMeshLayerProfileResults >();
110 mResults->mLayer = mLayer;
111 mResults->mId = mId;
112 mResults->copyPropertiesFromGenerator( this );
113
114 // we don't currently have any method to determine line->mesh intersection points, so for now we just sample at about 100(?) points over the line
115 const double curveLength = transformedCurve.length();
116
117 if ( !std::isnan( mStepDistance ) )
118 transformedCurve = transformedCurve.densifyByDistance( mStepDistance );
119 else
120 transformedCurve = transformedCurve.densifyByDistance( curveLength / 100 );
121
122 if ( mFeedback->isCanceled() )
123 return false;
124
125 for ( auto it = transformedCurve.vertices_begin(); it != transformedCurve.vertices_end(); ++it )
126 {
127 if ( mFeedback->isCanceled() )
128 return false;
129
130 QgsPoint point = ( *it );
131 const double height = heightAt( point.x(), point.y() );
132
133 try
134 {
135 point.transform( mLayerToTargetTransform );
136 }
137 catch ( QgsCsException & )
138 {
139 continue;
140 }
141 mResults->mRawPoints.append( QgsPoint( point.x(), point.y(), height ) );
142 }
143
144 if ( mFeedback->isCanceled() )
145 return false;
146
147 // convert x/y values back to distance/height values
148 QgsGeos originalCurveGeos( mProfileCurve.get() );
149 originalCurveGeos.prepareGeometry();
150 QString lastError;
151 for ( const QgsPoint &pixel : std::as_const( mResults->mRawPoints ) )
152 {
153 if ( mFeedback->isCanceled() )
154 return false;
155
156 const double distance = originalCurveGeos.lineLocatePoint( pixel, &lastError );
157
158 if ( !std::isnan( pixel.z() ) )
159 {
160 mResults->minZ = std::min( pixel.z(), mResults->minZ );
161 mResults->maxZ = std::max( pixel.z(), mResults->maxZ );
162 }
163 mResults->mDistanceToHeightMap.insert( distance, pixel.z() );
164 }
165
166 return true;
167}
168
173
175{
176 return mFeedback.get();
177}
178
179double QgsMeshLayerProfileGenerator::heightAt( double x, double y )
180{
181 return QgsMeshLayerUtils::interpolateZForPoint( mTriangularMesh, x, y ) * mScale + mOffset;
182}
183
@ Reverse
Reverse/inverse transform (from destination to source)
Abstract base class for storage of elevation profiles.
Abstract base class for objects which generate elevation profiles which represent a continuous surfac...
QVector< QgsProfileIdentifyResults > identify(const QgsProfilePoint &point, const QgsProfileIdentifyContext &context) override
Identify results visible at the specified profile point.
Class for doing transforms between two map coordinate systems.
Custom exception class for Coordinate Reference System related exceptions.
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition qgsfeedback.h:44
A geometry is the spatial representation of a feature.
double length() const
Returns the planar, 2-dimensional length of geometry.
QgsGeometry densifyByDistance(double distance) const
Densifies the geometry by adding regularly placed extra nodes inside each segment so that the maximum...
Qgis::GeometryOperationResult transform(const QgsCoordinateTransform &ct, Qgis::TransformDirection direction=Qgis::TransformDirection::Forward, bool transformZ=false)
Transforms this geometry as described by the coordinate transform ct.
QgsAbstractGeometry::vertex_iterator vertices_begin() const
Returns STL-style iterator pointing to the first vertex of the geometry.
QgsAbstractGeometry::vertex_iterator vertices_end() const
Returns STL-style iterator pointing to the imaginary vertex after the last vertex of the geometry.
Does vector analysis using the geos library and handles import, export, exception handling*.
Definition qgsgeos.h:98
void prepareGeometry() override
Prepares the geometry, so that subsequent calls to spatial relation methods are much faster.
Definition qgsgeos.cpp:252
double lineLocatePoint(const QgsPoint &point, QString *errorMsg=nullptr) const
Returns a distance representing the location along this linestring of the closest point on this lines...
Definition qgsgeos.cpp:2916
~QgsMeshLayerProfileGenerator() override
QgsFeedback * feedback() const override
Access to feedback object of the generator (may be nullptr)
QgsMeshLayerProfileGenerator(QgsMeshLayer *layer, const QgsProfileRequest &request)
Constructor for QgsMeshLayerProfileGenerator.
QgsAbstractProfileResults * takeResults() override
Takes results from the generator.
bool generateProfile(const QgsProfileGenerationContext &context=QgsProfileGenerationContext()) override
Generate the profile (based on data stored in the class).
QString sourceId() const override
Returns a unique identifier representing the source of the profile.
QString type() const override
Returns the unique string identifier for the results type.
QVector< QgsProfileIdentifyResults > identify(const QgsProfilePoint &point, const QgsProfileIdentifyContext &context) override
Identify results visible at the specified profile point.
Represents a mesh layer supporting display of data on structured or unstructured meshes.
void updateTriangularMesh(const QgsCoordinateTransform &transform=QgsCoordinateTransform())
Gets native mesh and updates (creates if it doesn't exist) the base triangular mesh.
QgsMapLayerElevationProperties * elevationProperties() override
Returns the layer's elevation properties.
QgsTriangularMesh * triangularMesh(double minimumTriangleSize=0) const
Returns triangular mesh (nullptr before rendering or calling to updateMesh).
Point geometry type, with support for z-dimension and m-values.
Definition qgspoint.h:49
double x
Definition qgspoint.h:52
void transform(const QgsCoordinateTransform &ct, Qgis::TransformDirection d=Qgis::TransformDirection::Forward, bool transformZ=false) override
Transforms the geometry using a coordinate transform.
Definition qgspoint.cpp:379
double y
Definition qgspoint.h:53
Encapsulates the context in which an elevation profile is to be generated.
Encapsulates the context of identifying profile results.
Stores identify results generated by a QgsAbstractProfileResults object.
Encapsulates a point on a distance-elevation profile.
Encapsulates properties and constraints relating to fetching elevation profiles from different source...
#define QgsDebugError(str)
Definition qgslogger.h:38
const QgsCoordinateReferenceSystem & crs