Collaboration diagram for osgEarth::GeoHeightField:

Public Member Functions
	GeoHeightField ()
	GeoHeightField (osg::HeightField heightField, const GeoExtent &extent, const VerticalSpatialReference vsrs)
bool	valid () const
bool	getElevation (const SpatialReference inputSRS, double x, double y, ElevationInterpolation interp, const VerticalSpatialReference outputVSRS, float &out_elevation) const
GeoHeightField	createSubSample (const GeoExtent &destEx, ElevationInterpolation interpolation) const
const GeoExtent &	getExtent () const
const osg::HeightField *	getHeightField () const
osg::HeightField *	getHeightField ()
osg::HeightField *	takeHeightField ()
Static Public Attributes
static GeoHeightField	INVALID
Protected Attributes
osg::ref_ptr< osg::HeightField >	_heightField
GeoExtent	_extent
osg::ref_ptr< const VerticalSpatialReference >	_vsrs

Detailed Description

A georeferenced heightfield.

Definition at line 337 of file GeoData.

Constructor & Destructor Documentation

GeoHeightField::GeoHeightField ( )

Constructs an empty (invalid) heightfield.

Definition at line 977 of file GeoData.cpp.

                               :
_heightField( 0L ),
_extent( GeoExtent::INVALID ),
_vsrs( 0L )
{
    //nop
}

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GeoHeightField::GeoHeightField	(	osg::HeightField *	heightField,
		const GeoExtent &	extent,
		const VerticalSpatialReference *	vsrs
	)

Constructs a new georeferenced heightfield.

Definition at line 985 of file GeoData.cpp.

                                                                     :
_heightField( heightField ),
_extent( extent ),
_vsrs( vsrs )
{
    if ( _heightField )
    {
        double minx, miny, maxx, maxy;
        _extent.getBounds(minx, miny, maxx, maxy);

        _heightField->setOrigin( osg::Vec3d( minx, miny, 0.0 ) );
        _heightField->setXInterval( (maxx - minx)/(double)(_heightField->getNumColumns()-1) );
        _heightField->setYInterval( (maxy - miny)/(double)(_heightField->getNumRows()-1) );
        _heightField->setBorderWidth( 0 );
    }
}

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Member Function Documentation

GeoHeightField GeoHeightField::createSubSample	(	const GeoExtent &	destEx,
		ElevationInterpolation	interpolation
	)		const

Subsamples the heightfield, returning a new heightfield corresponding to the destEx extent. The destEx must be a smaller, inset area of sourceEx.

Definition at line 1062 of file GeoData.cpp.

{
    double div = destEx.width()/_extent.width();
    if ( div >= 1.0f )
        return GeoHeightField::INVALID;

    int w = _heightField->getNumColumns();
    int h = _heightField->getNumRows();
    //double dx = _heightField->getXInterval() * div;
    //double dy = _heightField->getYInterval() * div;
    double xInterval = _extent.width() / (double)(_heightField->getNumColumns()-1);
    double yInterval = _extent.height() / (double)(_heightField->getNumRows()-1);
    double dx = xInterval * div;
    double dy = yInterval * div;

    osg::HeightField* dest = new osg::HeightField();
    dest->allocate( w, h );
    dest->setXInterval( dx );
    dest->setYInterval( dy );

    // copy over the skirt height, adjusting it for tile size.
    dest->setSkirtHeight( _heightField->getSkirtHeight() * div );

    double x, y;
    int col, row;

    for( x = destEx.xMin(), col=0; col < w; x += dx, col++ )
    {
        for( y = destEx.yMin(), row=0; row < h; y += dy, row++ )
        {
            float height = HeightFieldUtils::getHeightAtLocation( _heightField.get(), x, y, _extent.xMin(), _extent.yMin(), xInterval, yInterval, interpolation);
            dest->setHeight( col, row, height );
        }
    }

    osg::Vec3d orig( destEx.xMin(), destEx.yMin(), _heightField->getOrigin().z() );
    dest->setOrigin( orig );

    return GeoHeightField( dest, destEx, _vsrs.get() );
}

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bool GeoHeightField::getElevation	(	const SpatialReference *	inputSRS,
		double	x,
		double	y,
		ElevationInterpolation	interp,
		const VerticalSpatialReference *	outputVSRS,
		float &	out_elevation
	)		const

Gets the elevation value at a specified point.

Parameters:

srs	Spatial reference of the query coordinates. (If you pass in NULL, the method will assume that the SRS is equivalent to that of the GeoHeightField. Be sure this is case of you will get incorrect results.)
x,y	Coordinates at which to query the elevation value.
interp	Interpolation method for the elevation query.
outputVSRS	Convert the output elevation value to this VSRS (NULL to ignore)
out_elevation	Output: the elevation value

Returns:: True if the elevation query was succesful; false if not (e.g. if the query fell outside the geospatial extent of the heightfield)

Definition at line 1005 of file GeoData.cpp.

{
    double local_x = x, local_y = y;

    if ( inputSRS && !inputSRS->transform2D(x, y, _extent.getSRS(), local_x, local_y) )
        return false;

    if ( _extent.contains(local_x, local_y) )
    {
        double xInterval = _extent.width()  / (double)(_heightField->getNumColumns()-1);
        double yInterval = _extent.height() / (double)(_heightField->getNumRows()-1);

        elevation = HeightFieldUtils::getHeightAtLocation(
            _heightField.get(), 
            local_x, local_y, 
            _extent.xMin(), _extent.yMin(), 
            xInterval, yInterval, 
            interp);

        if ( elevation != NO_DATA_VALUE )
        {
            if ( VerticalSpatialReference::canTransform( _vsrs.get(), outputVSRS ) )
            {
                // need geodetic coordinates for a VSRS transformation:
                double lat_deg, lon_deg, newElevation;

                if ( inputSRS->isGeographic() ) {
                    lat_deg = y;
                    lon_deg = x;
                }
                else if ( _extent.getSRS()->isGeographic() ) {
                    lat_deg = local_y;
                    lon_deg = local_x;
                }
                else {
                    _extent.getSRS()->transform2D( x, y, inputSRS->getGeographicSRS(), lon_deg, lat_deg );
                }

                if ( _vsrs->transform( outputVSRS, lat_deg, lon_deg, elevation, newElevation ) )
                    elevation = newElevation;
            }
        }

        return true;
    }
    else
    {
        elevation = 0.0f;
        return false;
    }
}