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Hillshaderenderer: Add 'multidirectional oblique-weighted' rendering …

…option (#3160)
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AsgerPetersen authored and NathanW2 committed Jun 1, 2016
1 parent 0272ebc commit d47fe0f7b703611fdc12d730e7033111b9fcd40f
@@ -46,6 +46,12 @@ class QgsHillshadeRenderer : QgsRasterRenderer
*/
double zFactor() const;

/**
* @brief Is Multi Directional
* @return Is Multi Directional
*/
bool multiDirectional() const;


/**
* @brief Set the azimith of the light source.
@@ -64,4 +70,10 @@ class QgsHillshadeRenderer : QgsRasterRenderer
* @param zfactor The z factor.
*/
void setZFactor( double zfactor );

/**
* @brief Set Is Multi Directional
* @param isMultiDirectional Is multi directional
*/
void setMultiDirectional( bool isMultiDirectional );
};
@@ -51,6 +51,12 @@ class QgsHillshadeRendererWidget: QgsRasterRendererWidget
*/
double zFactor() const;

/**
* @brief multiDirectional
* @return multiDirectional
*/
bool multiDirectional() const;

public slots:
/**
* @brief Set the altitude of the light source
@@ -69,4 +75,10 @@ class QgsHillshadeRendererWidget: QgsRasterRendererWidget
* @param zfactor The z factor.
*/
void setZFactor( double zfactor );

/**
* @brief set MultiDirectional
* @param isMultiDirectional
*/
void setMultiDirectional( bool isMultiDirectional);
};
@@ -30,6 +30,7 @@ QgsHillshadeRenderer::QgsHillshadeRenderer( QgsRasterInterface *input, int band,
, mZFactor( 1 )
, mLightAngle( lightAngle )
, mLightAzimuth( lightAzimuth )
, mMultiDirectional( false )
{

}
@@ -38,6 +39,7 @@ QgsHillshadeRenderer *QgsHillshadeRenderer::clone() const
{
QgsHillshadeRenderer* r = new QgsHillshadeRenderer( nullptr, mBand, mLightAzimuth, mLightAngle );
r->setZFactor( mZFactor );
r->setMultiDirectional( mMultiDirectional );
return r;
}

@@ -52,8 +54,10 @@ QgsRasterRenderer *QgsHillshadeRenderer::create( const QDomElement &elem, QgsRas
double azimuth = elem.attribute( "azimuth", "315" ).toDouble();
double angle = elem.attribute( "angle", "45" ).toDouble();
double zFactor = elem.attribute( "zfactor", "1" ).toDouble();
int multiDirection = elem.attribute( "multidirection", "0" ).toInt();
QgsHillshadeRenderer* r = new QgsHillshadeRenderer( input, band, azimuth , angle );
r->setZFactor( zFactor );
r->setMultiDirectional( multiDirection > 0 );
return r;
}

@@ -71,6 +75,7 @@ void QgsHillshadeRenderer::writeXML( QDomDocument &doc, QDomElement &parentElem
rasterRendererElem.setAttribute( "azimuth", QString::number( mLightAzimuth ) );
rasterRendererElem.setAttribute( "angle", QString::number( mLightAngle ) );
rasterRendererElem.setAttribute( "zfactor", QString::number( mZFactor ) );
rasterRendererElem.setAttribute( "multidirection", QString::number( mMultiDirectional ) );
parentElem.appendChild( rasterRendererElem );
}

@@ -106,6 +111,12 @@ QgsRasterBlock *QgsHillshadeRenderer::block( int bandNo, const QgsRectangle &ext
double cosZenithRad = cos( zenithRad );
double sinZenithRad = sin( zenithRad );

// Multi direction hillshade: http://pubs.usgs.gov/of/1992/of92-422/of92-422.pdf
double angle0Rad = (-1 * mLightAzimuth - 45 - 45 * 0.5) * M_PI / 180.0;
double angle1Rad = (-1 * mLightAzimuth - 45 * 0.5) * M_PI / 180.0;
double angle2Rad = (-1 * mLightAzimuth + 45 * 0.5) * M_PI / 180.0;
double angle3Rad = (-1 * mLightAzimuth + 45 + 45 * 0.5) * M_PI / 180.0;

QRgb myDefaultColor = NODATA_COLOR;

for ( qgssize i = 0; i < ( qgssize )height; i++ )
@@ -181,14 +192,39 @@ QgsRasterBlock *QgsHillshadeRenderer::block( int bandNo, const QgsRectangle &ext
double derX = calcFirstDerX( x11, x21, x31, x12, x22, x32, x13, x23, x33, cellXSize );
double derY = calcFirstDerY( x11, x21, x31, x12, x22, x32, x13, x23, x33, cellYSize );

double slope_rad = atan( mZFactor * sqrt( derX * derX + derY * derY ) );
double slopeRad = atan( mZFactor * sqrt( derX * derX + derY * derY ) );
double aspectRad = atan2( derX, -derY );

double colorvalue = qBound( 0.0, 255.0 * (( cosZenithRad * cos( slope_rad ) ) +
( sinZenithRad * sin( slope_rad ) *
cos( azimuthRad - aspectRad ) ) ), 255.0 );

outputBlock->setColor( i, j, qRgb( colorvalue, colorvalue, colorvalue ) );
double grayValue;
if( !mMultiDirectional )
{
// Standard single direction hillshade
grayValue = qBound( 0.0, 255.0 * ( cosZenithRad * cos( slopeRad )
+ sinZenithRad * sin( slopeRad )
* cos( azimuthRad - aspectRad )) , 255.0 );
}
else
{
// Weighted multi direction as in http://pubs.usgs.gov/of/1992/of92-422/of92-422.pdf
double weight0 = sin( aspectRad - angle0Rad );
double weight1 = sin( aspectRad - angle1Rad );
double weight2 = sin( aspectRad - angle2Rad );
double weight3 = sin( aspectRad - angle3Rad );
weight0 = weight0 * weight0;
weight1 = weight1 * weight1;
weight2 = weight2 * weight2;
weight3 = weight3 * weight3;

double cosSlope = cosZenithRad * cos( slopeRad );
double sinSlope = sinZenithRad * sin( slopeRad );
double color0 = cosSlope + sinSlope * cos( angle0Rad - aspectRad ) ;
double color1 = cosSlope + sinSlope * cos( angle1Rad - aspectRad ) ;
double color2 = cosSlope + sinSlope * cos( angle2Rad - aspectRad ) ;
double color3 = cosSlope + sinSlope * cos( angle3Rad - aspectRad ) ;
grayValue = qBound(0.0, 255 * ( weight0 * color0 + weight1 * color1 + weight2 * color2 + weight3 * color3 ) * 0.5, 255.0);
}
outputBlock->setColor( i, j, qRgb( grayValue, grayValue, grayValue ) );
}
}
return outputBlock;
@@ -84,6 +84,12 @@ class CORE_EXPORT QgsHillshadeRenderer : public QgsRasterRenderer
*/
double zFactor() const { return mZFactor; }

/**
* @brief Is Multi Directional
* @return Is Multi Directional
*/
bool multiDirectional() const { return mMultiDirectional; }

/**
* @brief Set the azimith of the light source.
* @param azimuth The azimuth of the light source.
@@ -102,11 +108,18 @@ class CORE_EXPORT QgsHillshadeRenderer : public QgsRasterRenderer
*/
void setZFactor( double zfactor ) { mZFactor = zfactor; }

/**
* @brief Set Is Multi Directional
* @param isMultiDirectional Is multi directional
*/
void setMultiDirectional( bool isMultiDirectional ){ mMultiDirectional = isMultiDirectional; }

private:
int mBand;
double mZFactor;
double mLightAngle;
double mLightAzimuth;
bool mMultiDirectional;

/** Calculates the first order derivative in x-direction according to Horn (1981)*/
double calcFirstDerX( double x11, double x21, double x31, double x12, double x22, double x32, double x13, double x23, double x33 , double cellsize );
@@ -40,6 +40,8 @@ QgsHillshadeRendererWidget::QgsHillshadeRendererWidget( QgsRasterLayer *layer, c
mZFactor->setValue( 1 );
mZFactor->setClearValue( 1 );

mMultiDirection->setChecked( false );

if ( mRasterLayer )
{
QgsRasterDataProvider* provider = mRasterLayer->dataProvider();
@@ -63,6 +65,7 @@ QgsHillshadeRendererWidget::QgsHillshadeRendererWidget( QgsRasterLayer *layer, c
connect( mLightAzimuth, SIGNAL( valueChanged( double ) ), this, SLOT( on_mLightAzimuth_updated( double ) ) );
connect( mLightAzimuthDial, SIGNAL( valueChanged( int ) ), this, SLOT( on_mLightAzimuthDail_updated( int ) ) );
connect( mZFactor, SIGNAL( valueChanged( double ) ), this, SIGNAL( widgetChanged() ) );
connect( mMultiDirection, SIGNAL( stateChanged( int )), this, SIGNAL( widgetChanged() ) );

QgsBilinearRasterResampler* zoomedInResampler = new QgsBilinearRasterResampler();
layer->resampleFilter()->setZoomedInResampler( zoomedInResampler );
@@ -91,6 +94,7 @@ QgsRasterRenderer *QgsHillshadeRendererWidget::renderer()
QgsHillshadeRenderer* renderer = new QgsHillshadeRenderer( provider, band, mLightAzimuth->value(), mLightAngle->value() );
double value = mZFactor->value();
renderer->setZFactor( value );
renderer->setMultiDirectional( mMultiDirection->checkState() );
return renderer;
}

@@ -103,6 +107,7 @@ void QgsHillshadeRendererWidget::setFromRenderer( const QgsRasterRenderer *rende
mLightAngle->setValue( r->altitude() );
mLightAzimuth->setValue( r->azimuth() );
mZFactor->setValue( r->zFactor() );
mMultiDirection->setChecked( r->multiDirectional() );
}
}

@@ -121,6 +126,11 @@ void QgsHillshadeRendererWidget::setZFactor( double zfactor )
mZFactor->setValue( zfactor );
}

void QgsHillshadeRendererWidget::setMultiDirectional(bool isMultiDirectional )
{
mMultiDirection->setChecked( isMultiDirectional );
}

void QgsHillshadeRendererWidget::on_mLightAzimuth_updated( double value )
{
int newvalue = ( int )value - 180;
@@ -153,3 +163,8 @@ double QgsHillshadeRendererWidget::zFactor() const
{
return mZFactor->value();
}

bool QgsHillshadeRendererWidget::multiDirectional() const
{
return mMultiDirection->isChecked();
}
@@ -77,6 +77,12 @@ class GUI_EXPORT QgsHillshadeRendererWidget: public QgsRasterRendererWidget, pri
*/
double zFactor() const;

/**
* @brief multiDirection
* @return multiDirection
*/
bool multiDirectional() const;

public slots:
/**
* @brief Set the altitude of the light source
@@ -96,6 +102,12 @@ class GUI_EXPORT QgsHillshadeRendererWidget: public QgsRasterRendererWidget, pri
*/
void setZFactor( double zfactor );

/**
* @brief set MultiDirection
* @param isMultiDirection
*/
void setMultiDirectional( bool isMultiDirectional);

private slots:
void on_mLightAzimuth_updated( double value );
void on_mLightAzimuthDail_updated( int value );
@@ -99,7 +99,7 @@
</property>
</widget>
</item>
<item row="4" column="0" colspan="3">
<item row="5" column="0" colspan="3">
<spacer name="verticalSpacer">
<property name="orientation">
<enum>Qt::Vertical</enum>
@@ -135,6 +135,20 @@
</property>
</widget>
</item>
<item row="4" column="2">
<widget class="QCheckBox" name="mMultiDirection">
<property name="text">
<string/>
</property>
</widget>
</item>
<item row="4" column="0">
<widget class="QLabel" name="label_5">
<property name="text">
<string>Multidirectional</string>
</property>
</widget>
</item>
</layout>
</widget>
<customwidgets>

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