luciad::Map::HeightProvider Class Reference

A height provider based on the map layers order and visibility. More...

#include <luciad/maps/Map.h>

Public Member Functions
virtual	~HeightProvider ()=default
virtual std::optional< double >	retrieveHeightAt (const Point &point, const PixelDensity &pixelDensity, bool interpolate) const =0
	Return an elevation value at the provided point at a provided pixel density. More...
virtual std::optional< double >	retrieveHeightAt (Coordinate pixelCoordinate, bool interpolate) const =0
	Return an elevation value at a specified pixel that corresponds with what is visible on the map. More...

Detailed Description

A height provider based on the map layers order and visibility.

This class is thread safe. Related article: Retrieving height data. Related article: Retrieving height data.

Since

2023.0

Constructor & Destructor Documentation

~HeightProvider()

virtual luciad::Map::HeightProvider::~HeightProvider ( )

virtualdefault

Member Function Documentation

retrieveHeightAt() [1/2]

virtual std::optional< double > luciad::Map::HeightProvider::retrieveHeightAt ( const Point &  point, const PixelDensity &  pixelDensity, bool  interpolate  ) const

pure virtual

Return an elevation value at the provided point at a provided pixel density.

The Map::HeightProvider loops over all visible elevation raster models loaded on the map, from top to bottom, searching for the first model with a tile in the underlying raster data covering the specified point and with a pixel density equal or lower to the specified density. If elevation data is found, it is returned in the map reference unit of measure, std::nullopt otherwise.

Using interpolation makes sure that neighbouring height values form a smoother curve.

Parameters

point	the point for which the height is requested.
pixelDensity	the pixel density used to determine the level of detail to be used in the underlying data of each elevation model. Must be in the same coordinate reference of the provided point.
interpolate	bilinear interpolation is used if true, nearest neighbor if false.

Returns

the height expressed in the map reference unit of measure, or std::nullopt if no data is available for this point.

Exceptions

luciad::InvalidArgumentException

when the provided point and pixel density have different coordinate reference systems.

Remarks

this method is thread safe, you can call it from any thread.

Since

2024.0

retrieveHeightAt() [2/2]

virtual std::optional< double > luciad::Map::HeightProvider::retrieveHeightAt ( Coordinate  pixelCoordinate, bool  interpolate  ) const

pure virtual

Return an elevation value at a specified pixel that corresponds with what is visible on the map.

The ´Map::HeightProvider´ loops over all the visible elevation raster model loaded on the map in a top to bottom fashion in search for elevation data. It Looks for the first model with a tile in the underlying raster data covering the specified pixel point. The pixel density used for the retrieveHeightAt call is based on the camera position and pixel queried. if elevation data is found it will be returned in the map reference unit of measure, std::nullopt otherwise.

Using interpolation makes sure that neighbouring height values form a smoother curve.

Parameters

pixelCoordinate	The pixel for which the height is requested. in device independent pixels coordinate.
interpolate	bilinear interpolation is used if true, nearest neighbour if false. Enabling bilinear interpolation results in a smoother curve for neighboring samples, at the cost of a minor performance decrease.

Returns

the height expressed in the map reference unit of measure, or std::nullopt if no data is available for this pixel coordinate.

Remarks

this method is thread safe, you can call it from any thread.