void HeatmapGui::updateBBox()
{
// Set the row/cols and cell sizes here
QgsVectorLayer *inputLayer = inputVectorLayer();
if ( !inputLayer )
return;
mBBox = inputLayer->extent();
QgsCoordinateReferenceSystem layerCrs = inputLayer->crs();
double radiusInMapUnits = 0.0;
if ( mRadiusFieldCheckBox->isChecked() )
{
int idx = inputLayer->fields().indexFromName( mRadiusFieldCombo->currentField() );
double maxInField = inputLayer->maximumValue( idx ).toDouble();
if ( mRadiusFieldUnitCombo->currentIndex() == HeatmapGui::LayerUnits )
{
radiusInMapUnits = mapUnitsOf( maxInField, layerCrs );
}
else if ( mRadiusFieldUnitCombo->currentIndex() == HeatmapGui::MapUnits )
{
radiusInMapUnits = maxInField;
}
}
else
{
double radiusValue = mBufferSizeLineEdit->text().toDouble();
if ( mBufferUnitCombo->currentIndex() == HeatmapGui::LayerUnits )
{
radiusInMapUnits = mapUnitsOf( radiusValue, layerCrs );
}
else if ( mBufferUnitCombo->currentIndex() == HeatmapGui::MapUnits )
{
radiusInMapUnits = radiusValue;
}
}
// get the distance converted into map units
mBBox.setXMinimum( mBBox.xMinimum() - radiusInMapUnits );
mBBox.setYMinimum( mBBox.yMinimum() - radiusInMapUnits );
mBBox.setXMaximum( mBBox.xMaximum() + radiusInMapUnits );
mBBox.setYMaximum( mBBox.yMaximum() + radiusInMapUnits );
// Leave number of rows the same, and calculate new corresponding cell size and number of columns
mYcellsize = mBBox.height() / ( mRows - 1 );
mXcellsize = mYcellsize;
mColumns = max( mBBox.width() / mXcellsize + 1, 1 );
updateSize();
}
/*
* Estimate a good default radius for the heatmap, based on the
* bounding box size of the layer
*/
double HeatmapGui::estimateRadius()
{
QgsVectorLayer *inputLayer = inputVectorLayer();
// No input layer? Default to radius of 100
if ( !inputLayer )
return 100;
// Find max dimension of layer bounding box
QgsRectangle mExtent = inputLayer->extent();
double maxExtent = max( mExtent.width(), mExtent.height() );
// Return max dimension divided by 30. This is fairly arbitrary
// but approximately corresponds to the default value chosen by ArcMap
// TODO - a better solution is to let the data define the radius
// choice by setting the radius equal to the average Nearest
// Neighbour Index for the closest n points
double estimate = maxExtent / 30;
if ( mBufferUnitCombo->currentIndex() == HeatmapGui::LayerUnits )
{
// layer units selected, so convert estimate from map units
QgsCoordinateReferenceSystem layerCrs = inputLayer->crs();
estimate /= mapUnitsOf( 1, layerCrs );
}
// Make estimate pretty by rounding off to first digit only (eg 356->300, 0.567->0.5)
double tens = pow( 10, floor( log10( estimate ) ) );
return floor( estimate / tens + 0.5 ) * tens;
}
double HeatmapGui::radius() const
{
double radius = mBufferSizeLineEdit->text().toDouble();
if ( mBufferUnitCombo->currentIndex() == HeatmapGui::LayerUnits )
{
radius = mapUnitsOf( radius, inputVectorLayer()->crs() );
}
return radius;
}
// Slot called when the menu item is triggered
// If you created more menu items / toolbar buttons in initiGui, you should
// create a separate handler for each action - this single run() method will
// not be enough
void Heatmap::run()
{
HeatmapGui d( mQGisIface->mainWindow(), QgisGui::ModalDialogFlags, &mSessionSettings );
if ( d.exec() == QDialog::Accepted )
{
// everything runs here
// Get the required data from the dialog
QgsRectangle myBBox = d.bbox();
int columns = d.columns();
int rows = d.rows();
double cellsize = d.cellSizeX(); // or d.cellSizeY(); both have the same value
mDecay = d.decayRatio();
int kernelShape = d.kernelShape();
// Start working on the input vector
QgsVectorLayer* inputLayer = d.inputVectorLayer();
// Getting the rasterdataset in place
GDALAllRegister();
GDALDataset *emptyDataset;
GDALDriver *myDriver;
myDriver = GetGDALDriverManager()->GetDriverByName( d.outputFormat().toUtf8() );
if ( myDriver == NULL )
{
QMessageBox::information( 0, tr( "GDAL driver error" ), tr( "Cannot open the driver for the specified format" ) );
return;
}
double geoTransform[6] = { myBBox.xMinimum(), cellsize, 0, myBBox.yMinimum(), 0, cellsize };
emptyDataset = myDriver->Create( d.outputFilename().toUtf8(), columns, rows, 1, GDT_Float32, NULL );
emptyDataset->SetGeoTransform( geoTransform );
// Set the projection on the raster destination to match the input layer
emptyDataset->SetProjection( inputLayer->crs().toWkt().toLocal8Bit().data() );
GDALRasterBand *poBand;
poBand = emptyDataset->GetRasterBand( 1 );
poBand->SetNoDataValue( NO_DATA );
float* line = ( float * ) CPLMalloc( sizeof( float ) * columns );
for ( int i = 0; i < columns ; i++ )
{
line[i] = NO_DATA;
}
// Write the empty raster
for ( int i = 0; i < rows ; i++ )
{
poBand->RasterIO( GF_Write, 0, i, columns, 1, line, columns, 1, GDT_Float32, 0, 0 );
}
CPLFree( line );
//close the dataset
GDALClose(( GDALDatasetH ) emptyDataset );
// open the raster in GA_Update mode
GDALDataset *heatmapDS;
heatmapDS = ( GDALDataset * ) GDALOpen( d.outputFilename().toUtf8(), GA_Update );
if ( !heatmapDS )
{
QMessageBox::information( 0, tr( "Raster update error" ), tr( "Could not open the created raster for updating. The heatmap was not generated." ) );
return;
}
poBand = heatmapDS->GetRasterBand( 1 );
QgsAttributeList myAttrList;
int rField = 0;
int wField = 0;
// Handle different radius options
double radius;
double radiusToMapUnits = 1;
int myBuffer = 0;
if ( d.variableRadius() )
{
rField = d.radiusField();
myAttrList.append( rField );
QgsDebugMsg( QString( "Radius Field index received: %1" ).arg( rField ) );
// If not using map units, then calculate a conversion factor to convert the radii to map units
if ( d.radiusUnit() == HeatmapGui::Meters )
{
radiusToMapUnits = mapUnitsOf( 1, inputLayer->crs() );
}
}
else
{
radius = d.radius(); // radius returned by d.radius() is already in map units
myBuffer = bufferSize( radius, cellsize );
}
if ( d.weighted() )
{
wField = d.weightField();
myAttrList.append( wField );
}
// This might have attributes or mightnot have attibutes at all
// based on the variableRadius() and weighted()
QgsFeatureIterator fit = inputLayer->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( myAttrList ) );
int totalFeatures = inputLayer->featureCount();
int counter = 0;
QProgressDialog p( tr( "Creating heatmap" ), tr( "Abort" ), 0, totalFeatures, mQGisIface->mainWindow() );
p.setWindowModality( Qt::ApplicationModal );
p.show();
QgsFeature myFeature;
while ( fit.nextFeature( myFeature ) )
{
counter++;
p.setValue( counter );
QApplication::processEvents();
if ( p.wasCanceled() )
{
QMessageBox::information( 0, tr( "Heatmap generation aborted" ), tr( "QGIS will now load the partially-computed raster." ) );
break;
}
QgsGeometry* myPointGeometry;
myPointGeometry = myFeature.geometry();
// convert the geometry to point
QgsPoint myPoint;
myPoint = myPointGeometry->asPoint();
// avoiding any empty points or out of extent points
if (( myPoint.x() < myBBox.xMinimum() ) || ( myPoint.y() < myBBox.yMinimum() )
|| ( myPoint.x() > myBBox.xMaximum() ) || ( myPoint.y() > myBBox.yMaximum() ) )
{
continue;
}
// If radius is variable then fetch it and calculate new pixel buffer size
if ( d.variableRadius() )
{
radius = myFeature.attribute( rField ).toDouble() * radiusToMapUnits;
myBuffer = bufferSize( radius, cellsize );
}
int blockSize = 2 * myBuffer + 1; //Block SIDE would be more appropriate
// calculate the pixel position
unsigned int xPosition, yPosition;
xPosition = (( myPoint.x() - myBBox.xMinimum() ) / cellsize ) - myBuffer;
yPosition = (( myPoint.y() - myBBox.yMinimum() ) / cellsize ) - myBuffer;
// get the data
float *dataBuffer = ( float * ) CPLMalloc( sizeof( float ) * blockSize * blockSize );
poBand->RasterIO( GF_Read, xPosition, yPosition, blockSize, blockSize,
dataBuffer, blockSize, blockSize, GDT_Float32, 0, 0 );
double weight = 1.0;
if ( d.weighted() )
{
weight = myFeature.attribute( wField ).toDouble();
}
for ( int xp = 0; xp <= myBuffer; xp++ )
{
for ( int yp = 0; yp <= myBuffer; yp++ )
{
double distance = sqrt( pow( xp, 2.0 ) + pow( yp, 2.0 ) );
// is pixel outside search bandwidth of feature?
if ( distance > myBuffer )
{
continue;
}
double pixelValue = weight * calculateKernelValue( distance, myBuffer, kernelShape );
// clearing anamolies along the axes
if ( xp == 0 && yp == 0 )
{
pixelValue /= 4;
}
else if ( xp == 0 || yp == 0 )
{
pixelValue /= 2;
}
int pos[4];
pos[0] = ( myBuffer + xp ) * blockSize + ( myBuffer + yp );
pos[1] = ( myBuffer + xp ) * blockSize + ( myBuffer - yp );
pos[2] = ( myBuffer - xp ) * blockSize + ( myBuffer + yp );
pos[3] = ( myBuffer - xp ) * blockSize + ( myBuffer - yp );
for ( int p = 0; p < 4; p++ )
{
if ( dataBuffer[ pos[p] ] == NO_DATA )
{
dataBuffer[ pos[p] ] = 0;
}
dataBuffer[ pos[p] ] += pixelValue;
}
}
}
poBand->RasterIO( GF_Write, xPosition, yPosition, blockSize, blockSize,
dataBuffer, blockSize, blockSize, GDT_Float32, 0, 0 );
CPLFree( dataBuffer );
}
// Finally close the dataset
GDALClose(( GDALDatasetH ) heatmapDS );
// Open the file in QGIS window
mQGisIface->addRasterLayer( d.outputFilename(), QFileInfo( d.outputFilename() ).baseName() );
}
}
// Slot called when the menu item is triggered
// If you created more menu items / toolbar buttons in initiGui, you should
// create a separate handler for each action - this single run() method will
// not be enough
void Heatmap::run()
{
HeatmapGui d( mQGisIface->mainWindow(), QgisGui::ModalDialogFlags, &mSessionSettings );
//check that dialog found a suitable vector layer
if ( !d.inputVectorLayer() )
{
mQGisIface->messageBar()->pushMessage( tr( "Layer not found" ), tr( "The heatmap plugin requires at least one point vector layer" ), QgsMessageBar::INFO, mQGisIface->messageTimeout() );
return;
}
if ( d.exec() != QDialog::Accepted )
{
return;
}
QgsVectorLayer* inputLayer = d.inputVectorLayer();
// Get the required data from the dialog
QgsRectangle myBBox = d.bbox();
int columns = d.columns();
int rows = d.rows();
double cellsize = d.cellSizeX(); // or d.cellSizeY(); both have the same value
mDecay = d.decayRatio();
KernelShape kernelShape = d.kernelShape();
OutputValues valueType = d.outputValues();
//is input layer multipoint?
bool isMultiPoint = inputLayer->wkbType() == Qgis::WKBMultiPoint || inputLayer->wkbType() == Qgis::WKBMultiPoint25D;
// Getting the rasterdataset in place
GDALAllRegister();
GDALDriverH myDriver = GDALGetDriverByName( d.outputFormat().toUtf8() );
if ( !myDriver )
{
mQGisIface->messageBar()->pushMessage( tr( "GDAL driver error" ), tr( "Cannot open the driver for the specified format" ), QgsMessageBar::WARNING, mQGisIface->messageTimeout() );
return;
}
double geoTransform[6] = { myBBox.xMinimum(), cellsize, 0, myBBox.yMinimum(), 0, cellsize };
GDALDatasetH emptyDataset = GDALCreate( myDriver, d.outputFilename().toUtf8(), columns, rows, 1, GDT_Float32, nullptr );
GDALSetGeoTransform( emptyDataset, geoTransform );
// Set the projection on the raster destination to match the input layer
GDALSetProjection( emptyDataset, inputLayer->crs().toWkt().toLocal8Bit().data() );
GDALRasterBandH poBand = GDALGetRasterBand( emptyDataset, 1 );
GDALSetRasterNoDataValue( poBand, NO_DATA );
float* line = ( float * ) CPLMalloc( sizeof( float ) * columns );
for ( int i = 0; i < columns ; i++ )
{
line[i] = NO_DATA;
}
// Write the empty raster
for ( int i = 0; i < rows ; i++ )
{
if ( GDALRasterIO( poBand, GF_Write, 0, i, columns, 1, line, columns, 1, GDT_Float32, 0, 0 ) != CE_None )
{
QgsDebugMsg( "Raster IO Error" );
}
}
CPLFree( line );
//close the dataset
GDALClose( emptyDataset );
// open the raster in GA_Update mode
GDALDatasetH heatmapDS = GDALOpen( TO8F( d.outputFilename() ), GA_Update );
if ( !heatmapDS )
{
mQGisIface->messageBar()->pushMessage( tr( "Raster update error" ), tr( "Could not open the created raster for updating. The heatmap was not generated." ), QgsMessageBar::WARNING );
return;
}
poBand = GDALGetRasterBand( heatmapDS, 1 );
QgsAttributeList myAttrList;
int rField = 0;
int wField = 0;
// Handle different radius options
double radius;
double radiusToMapUnits = 1;
int myBuffer = 0;
if ( d.variableRadius() )
{
rField = d.radiusField();
myAttrList.append( rField );
QgsDebugMsg( QString( "Radius Field index received: %1" ).arg( rField ) );
// If not using map units, then calculate a conversion factor to convert the radii to map units
if ( d.radiusUnit() == HeatmapGui::LayerUnits )
{
radiusToMapUnits = mapUnitsOf( 1, inputLayer->crs() );
}
}
else
{
radius = d.radius(); // radius returned by d.radius() is already in map units
myBuffer = bufferSize( radius, cellsize );
}
if ( d.weighted() )
{
wField = d.weightField();
myAttrList.append( wField );
}
// This might have attributes or mightnot have attibutes at all
// based on the variableRadius() and weighted()
QgsFeatureIterator fit = inputLayer->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( myAttrList ) );
int totalFeatures = inputLayer->featureCount();
int counter = 0;
QProgressDialog p( tr( "Rendering heatmap..." ), tr( "Abort" ), 0, totalFeatures, mQGisIface->mainWindow() );
p.setWindowTitle( tr( "QGIS" ) );
p.setWindowModality( Qt::ApplicationModal );
p.show();
QgsFeature myFeature;
while ( fit.nextFeature( myFeature ) )
{
counter++;
p.setValue( counter );
QApplication::processEvents();
if ( p.wasCanceled() )
{
mQGisIface->messageBar()->pushMessage( tr( "Heatmap generation aborted" ), tr( "QGIS will now load the partially-computed raster" ), QgsMessageBar::INFO, mQGisIface->messageTimeout() );
break;
}
const QgsGeometry* featureGeometry = myFeature.constGeometry();
if ( !featureGeometry )
{
continue;
}
// convert the geometry to multipoint
QgsMultiPoint multiPoints;
if ( !isMultiPoint )
{
QgsPoint myPoint = featureGeometry->asPoint();
// avoiding any empty points or out of extent points
if (( myPoint.x() < myBBox.xMinimum() ) || ( myPoint.y() < myBBox.yMinimum() )
|| ( myPoint.x() > myBBox.xMaximum() ) || ( myPoint.y() > myBBox.yMaximum() ) )
{
continue;
}
multiPoints << myPoint;
}
else
{
multiPoints = featureGeometry->asMultiPoint();
}
// If radius is variable then fetch it and calculate new pixel buffer size
if ( d.variableRadius() )
{
radius = myFeature.attribute( rField ).toDouble() * radiusToMapUnits;
myBuffer = bufferSize( radius, cellsize );
}
int blockSize = 2 * myBuffer + 1; //Block SIDE would be more appropriate
double weight = 1.0;
if ( d.weighted() )
{
weight = myFeature.attribute( wField ).toDouble();
}
//loop through all points in multipoint
for ( QgsMultiPoint::const_iterator pointIt = multiPoints.constBegin(); pointIt != multiPoints.constEnd(); ++pointIt )
{
// avoiding any empty points or out of extent points
if ((( *pointIt ).x() < myBBox.xMinimum() ) || (( *pointIt ).y() < myBBox.yMinimum() )
|| (( *pointIt ).x() > myBBox.xMaximum() ) || (( *pointIt ).y() > myBBox.yMaximum() ) )
{
continue;
}
// calculate the pixel position
unsigned int xPosition, yPosition;
xPosition = ((( *pointIt ).x() - myBBox.xMinimum() ) / cellsize ) - myBuffer;
yPosition = ((( *pointIt ).y() - myBBox.yMinimum() ) / cellsize ) - myBuffer;
// get the data
float *dataBuffer = ( float * ) CPLMalloc( sizeof( float ) * blockSize * blockSize );
if ( GDALRasterIO( poBand, GF_Read, xPosition, yPosition, blockSize, blockSize,
dataBuffer, blockSize, blockSize, GDT_Float32, 0, 0 ) != CE_None )
{
QgsDebugMsg( "Raster IO Error" );
}
for ( int xp = 0; xp <= myBuffer; xp++ )
{
for ( int yp = 0; yp <= myBuffer; yp++ )
{
double distance = sqrt( pow( xp, 2.0 ) + pow( yp, 2.0 ) );
// is pixel outside search bandwidth of feature?
if ( distance > myBuffer )
{
continue;
}
double pixelValue = weight * calculateKernelValue( distance, myBuffer, kernelShape, valueType );
// clearing anamolies along the axes
if ( xp == 0 && yp == 0 )
{
pixelValue /= 4;
}
else if ( xp == 0 || yp == 0 )
{
pixelValue /= 2;
}
int pos[4];
pos[0] = ( myBuffer + xp ) * blockSize + ( myBuffer + yp );
pos[1] = ( myBuffer + xp ) * blockSize + ( myBuffer - yp );
pos[2] = ( myBuffer - xp ) * blockSize + ( myBuffer + yp );
pos[3] = ( myBuffer - xp ) * blockSize + ( myBuffer - yp );
for ( int p = 0; p < 4; p++ )
{
if ( dataBuffer[ pos[p] ] == NO_DATA )
{
dataBuffer[ pos[p] ] = 0;
}
dataBuffer[ pos[p] ] += pixelValue;
}
}
}
if ( GDALRasterIO( poBand, GF_Write, xPosition, yPosition, blockSize, blockSize,
dataBuffer, blockSize, blockSize, GDT_Float32, 0, 0 ) != CE_None )
{
QgsDebugMsg( "Raster IO Error" );
}
CPLFree( dataBuffer );
}
}
// Finally close the dataset
GDALClose(( GDALDatasetH ) heatmapDS );
// Open the file in QGIS window if requested
if ( d.addToCanvas() )
{
mQGisIface->addRasterLayer( d.outputFilename(), QFileInfo( d.outputFilename() ).baseName() );
}
}
