QGIS API Documentation 3.35.0-Master (ffb31addd7f)
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LinTriangleInterpolator.cpp
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1/***************************************************************************
2 LinTriangleInterpolator.cpp
3 ---------------------------
4 copyright : (C) 2004 by Marco Hugentobler
6 ***************************************************************************/
7
8/***************************************************************************
9 * *
10 * This program is free software; you can redistribute it and/or modify *
11 * it under the terms of the GNU General Public License as published by *
12 * the Free Software Foundation; either version 2 of the License, or *
13 * (at your option) any later version. *
14 * *
15 ***************************************************************************/
16
18#include "qgslogger.h"
19
20bool LinTriangleInterpolator::calcFirstDerX( double x, double y, Vector3D *vec )
21{
22
23 if ( vec && mTIN )
24 {
25 QgsPoint pt1( 0, 0, 0 );
26 QgsPoint pt2( 0, 0, 0 );
27 QgsPoint pt3( 0, 0, 0 );
28
29 if ( !mTIN->triangleVertices( x, y, pt1, pt2, pt3 ) )
30 {
31 return false;//point outside the convex hull or numerical problems
32 }
33
34 vec->setX( 1.0 );
35 vec->setY( 0.0 );
36 vec->setZ( ( pt1.z() * ( pt2.y() - pt3.y() ) + pt2.z() * ( pt3.y() - pt1.y() ) + pt3.z() * ( pt1.y() - pt2.y() ) ) / ( ( pt1.x() - pt2.x() ) * ( pt2.y() - pt3.y() ) - ( pt2.x() - pt3.x() ) * ( pt1.y() - pt2.y() ) ) );
37 return true;
38 }
39
40 else
41 {
42 QgsDebugError( QStringLiteral( "warning, null pointer" ) );
43 return false;
44 }
45}
46
47bool LinTriangleInterpolator::calcFirstDerY( double x, double y, Vector3D *vec )
48{
49 if ( vec && mTIN )
50 {
51 QgsPoint pt1( 0, 0, 0 );
52 QgsPoint pt2( 0, 0, 0 );
53 QgsPoint pt3( 0, 0, 0 );
54
55 if ( !mTIN->triangleVertices( x, y, pt1, pt2, pt3 ) )
56 {
57 return false;
58 }
59
60 vec->setX( 0 );
61 vec->setY( 1.0 );
62 vec->setZ( ( pt1.z() * ( pt2.x() - pt3.x() ) + pt2.z() * ( pt3.x() - pt1.x() ) + pt3.z() * ( pt1.x() - pt2.x() ) ) / ( ( pt1.y() - pt2.y() ) * ( pt2.x() - pt3.x() ) - ( pt2.y() - pt3.y() ) * ( pt1.x() - pt2.x() ) ) );
63 return true;
64 }
65
66 else
67 {
68 QgsDebugError( QStringLiteral( "warning, null pointer" ) );
69 return false;
70 }
71}
72
73bool LinTriangleInterpolator::calcNormVec( double x, double y, QgsPoint &vec )
74{
75//calculate vector product of the two derivative vectors in x- and y-direction and set the length to 1
76 if ( mTIN )
77 {
78 Vector3D vec1;
79 Vector3D vec2;
80 if ( !calcFirstDerX( x, y, &vec1 ) )
81 {return false;}
82 if ( !calcFirstDerY( x, y, &vec2 ) )
83 {return false;}
84 const Vector3D vec3( vec1.getY()*vec2.getZ() - vec1.getZ()*vec2.getY(), vec1.getZ()*vec2.getX() - vec1.getX()*vec2.getZ(), vec1.getX()*vec2.getY() - vec1.getY()*vec2.getX() );//calculate vector product
85 const double absvec3 = std::sqrt( vec3.getX() * vec3.getX() + vec3.getY() * vec3.getY() + vec3.getZ() * vec3.getZ() );//length of vec3
86 vec.setX( vec3.getX() / absvec3 );//standardize vec3 and assign it to vec
87 vec.setY( vec3.getY() / absvec3 );
88 vec.setZ( vec3.getZ() / absvec3 );
89 return true;
90 }
91
92 else
93 {
94 QgsDebugError( QStringLiteral( "warning, null pointer" ) );
95 return false;
96 }
97
98}
99
100bool LinTriangleInterpolator::calcPoint( double x, double y, QgsPoint &point )
101{
102 if ( mTIN )
103 {
104 QgsPoint pt1( 0, 0, 0 );
105 QgsPoint pt2( 0, 0, 0 );
106 QgsPoint pt3( 0, 0, 0 );
107
108 if ( !mTIN->triangleVertices( x, y, pt1, pt2, pt3 ) )
109 {
110 return false;//point is outside the convex hull or numerical problems
111 }
112
113 const double a = ( pt1.z() * ( pt2.y() - pt3.y() ) + pt2.z() * ( pt3.y() - pt1.y() ) + pt3.z() * ( pt1.y() - pt2.y() ) ) / ( ( pt1.x() - pt2.x() ) * ( pt2.y() - pt3.y() ) - ( pt2.x() - pt3.x() ) * ( pt1.y() - pt2.y() ) );
114 const double b = ( pt1.z() * ( pt2.x() - pt3.x() ) + pt2.z() * ( pt3.x() - pt1.x() ) + pt3.z() * ( pt1.x() - pt2.x() ) ) / ( ( pt1.y() - pt2.y() ) * ( pt2.x() - pt3.x() ) - ( pt2.y() - pt3.y() ) * ( pt1.x() - pt2.x() ) );
115 const double c = pt1.z() - a * pt1.x() - b * pt1.y();
116
117 point.setX( x );
118 point.setY( y );
119 point.setZ( a * x + b * y + c );
120 return true;
121 }
122 else
123 {
124 QgsDebugError( QStringLiteral( "warning, null pointer" ) );
125 return false;
126 }
127
128}
129
130
131
132
133
134
135
136
137
138
virtual bool calcFirstDerX(double x, double y, Vector3D *result)
Calculates the first derivative with respect to x for a linear surface and assigns it to vec.
bool calcNormVec(double x, double y, QgsPoint &result) override
Calculates the normal vector and assigns it to vec.
virtual bool calcFirstDerY(double x, double y, Vector3D *result)
Calculates the first derivative with respect to y for a linear surface and assigns it to vec.
QgsDualEdgeTriangulation * mTIN
bool calcPoint(double x, double y, QgsPoint &result) override
Performs a linear interpolation in a triangle and assigns the x-,y- and z-coordinates to point.
bool triangleVertices(double x, double y, QgsPoint &p1, int &n1, QgsPoint &p2, int &n2, QgsPoint &p3, int &n3) override
Finds out in which triangle the point with coordinates x and y is and assigns the numbers of the vert...
Point geometry type, with support for z-dimension and m-values.
Definition qgspoint.h:49
void setY(double y)
Sets the point's y-coordinate.
Definition qgspoint.h:291
void setX(double x)
Sets the point's x-coordinate.
Definition qgspoint.h:280
double z
Definition qgspoint.h:54
double x
Definition qgspoint.h:52
void setZ(double z)
Sets the point's z-coordinate.
Definition qgspoint.h:304
double y
Definition qgspoint.h:53
Class Vector3D represents a 3D-Vector, capable to store x-,y- and z-coordinates in double values.
Definition Vector3D.h:36
void setX(double x)
Sets the x-component of the vector.
Definition Vector3D.h:106
double getY() const
Returns the y-component of the vector.
Definition Vector3D.h:96
double getX() const
Returns the x-component of the vector.
Definition Vector3D.h:91
void setY(double y)
Sets the y-component of the vector.
Definition Vector3D.h:111
double getZ() const
Returns the z-component of the vector.
Definition Vector3D.h:101
void setZ(double z)
Sets the z-component of the vector.
Definition Vector3D.h:116
As part of the API refactoring and improvements which landed in the Processing API was substantially reworked from the x version This was done in order to allow much of the underlying Processing framework to be ported into c
#define QgsDebugError(str)
Definition qgslogger.h:38