NgaDigitalTerrainElevationData Class

A terrain provider for reading terrain from National Geospatial-Intelligence Agency (NGA) Digital Terrain Elevation Data (DTED) files.

Inheritance Hierarchy

SystemObject
AGI.Foundation.TerrainTerrainProvider
AGI.Foundation.TerrainNgaDigitalTerrainElevationData

Namespace: AGI.Foundation.Terrain
Assembly: AGI.Foundation.TerrainReaders (in AGI.Foundation.TerrainReaders.dll) Version: 24.3.420.0 (24.3.420.0)

Syntax

C++

Copy

public class NgaDigitalTerrainElevationData : TerrainProvider

Public Class NgaDigitalTerrainElevationData
	Inherits TerrainProvider

public ref class NgaDigitalTerrainElevationData : public TerrainProvider

type NgaDigitalTerrainElevationData =  
    class
        inherit TerrainProvider
    end

The NgaDigitalTerrainElevationData type exposes the following members.

Constructors

	Name	Description
	NgaDigitalTerrainElevationData(FileStreamFactory)	Initializes a new instance with the specified file stream factory for a DMED file.
	NgaDigitalTerrainElevationData(String)	Initializes a new instance using the specified DMED filename.
	NgaDigitalTerrainElevationData(FileStreamFactory, TerrainCacheGroup)	Initializes a new instance with the specified file stream factory for a DMED file.
	NgaDigitalTerrainElevationData(String, TerrainCacheGroup)	Initializes a new instance using the specified DMED filename.
	NgaDigitalTerrainElevationData(String, Int32, Int32, Int32, Int32)	Initializes a new instance with the specified information. If a DMED file is available for this data set, the constructor taking that file should be used instead.
	NgaDigitalTerrainElevationData(String, Int32, Int32, Int32, Int32, TerrainCacheGroup)	Initializes a new instance with the specified information. If a DMED file is available for this data set, the constructor taking that file should be used instead.

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Properties

	Name	Description
	BoundingExtent	Gets or sets the smallest rectangular extent that bounds the terrain provided by this terrain provider. The returned extent's edges are expressed in radians. (Inherited from TerrainProvider.)
	BoundingExtentNativeUnits	Gets or sets the smallest rectangular extent that bounds the terrain provided by this terrain provider. The returned extent's edges are expressed in the native units of the terrain provider. (Inherited from TerrainProvider.)
	CacheGroup	Gets the TerrainCacheGroup that contains this provider.
	HeightReference	Gets or sets an enumeration indicating whether the heights returned by the GetHeight(Double, Double) method are relative to the Shape or to the ReferenceSurface. (Inherited from TerrainProvider.)
	MinimumSampleSpacing	Gets the smallest distance between the successive height samples of the terrain data, in radians. If the return value is 0.0, then the minimum sample spacing is unknown. (Overrides TerrainProviderMinimumSampleSpacing.)
	NativeToMeters	Gets or sets the value to multiply a height in the native units of the terrain provider to convert it to meters. (Inherited from TerrainProvider.)
	RadiansToNative	Gets or sets the value to multiply an angle in radians by in order to convert it to the internal units of the terrain provider. (Inherited from TerrainProvider.)
	ReferenceSurface	Gets or sets the reference surface. The GetHeight(Double, Double) method returns heights relative to this reference surface. If this property is , the heights are relative to the surface of the Shape ellipsoid instead. (Inherited from TerrainProvider.)
	Shape	Gets or sets the shape on which the longitude and latitude are defined. If ReferenceSurface is , the heights returned by GetHeight(Double, Double) are relative to this ellipsoid as well. (Inherited from TerrainProvider.)
	ShapeFixedFrame	Gets or sets the reference frame fixed to the Shape in which the longitude and latitude are defined. (Inherited from TerrainProvider.)

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Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetFirstPartials	Get the partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape. (Overrides TerrainProviderGetFirstPartials(Double, Double).)
	GetGradient	Get the interpolated gradient of height with respect to the terrain at the specified longitude and latitude relative to the provider's Shape. This method produces a vector representing the gradient of height in the ShapeFixedFrame. Note: The direction for the gradient is defined for use as the outward facing surface normal direction. To obtain the directional derivative for the height (rate of change of height with respect to time), take the negative gradient and dot it with a unit vector along the desired azimuth (change in height with respect to distance), times the speed along that direction in meters/second. The gradient, as defined above, is parallel to the upward facing terrain surface normal, but its magnitude indicates the rate of change in the height at that location. (Inherited from TerrainProvider.)
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetHeight	Gets the interpolated height of the terrain at the specified longitude and latitude using the default interpolator for this terrain provider. (Overrides TerrainProviderGetHeight(Double, Double).)
	GetHeightNativeUnits	Gets the interpolated height of the terrain at the specified longitude and latitude. (Overrides TerrainProviderGetHeightNativeUnits(Double, Double).)
	GetHeightRelativeToShape	Gets the interpolated height of the terrain at the specified longitude and latitude relative to the provider's Shape. This method takes into account the heights of any reference surfaces. (Inherited from TerrainProvider.)
	GetHessian	Get the interpolated hessian matrix based on the function of height with respect to the specified longitude and latitude relative to the provider's Shape. This method produces a matrix representing the mixed second order partial derivatives of height in the ShapeFixedFrame. Note: The direction for the gradient and hessian is defined for use with the directional derivative on the surface. The gradient is defined to be orthogonal to the terrain surface with its surface projection in the direction of the greatest increase in the height. To obtain the second directional derivative for the height (acceleration of height along a particular azimuth), take the negative of the hessian then pre and post multiply it by the velocity vector along the desired azimuth. Then add the negative gradient dotted with the derivative of the velocity vector along the surface. (Inherited from TerrainProvider.)
	GetLocalMinimumSampleSpacing	Gets the smallest distance between the successive height samples of the terrain data, in radians, at the specified coordinates. If the return value is 0.0, then the minimum sample spacing is unknown. (Inherited from TerrainProvider.)
	GetNormal	Get the normal vector to the terrain surface at the specified location. (Inherited from TerrainProvider.)
	GetSecondPartials	Get the second order (mixed) partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape. (Overrides TerrainProviderGetSecondPartials(Double, Double).)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	InGlobalBounds	Returns if the coordinates are in global bounds which is: [-π, π] for longitude and [-π/2, π/2] for latitude. (Inherited from TerrainProvider.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	PreloadExtent	Loads the terrain data in a given CartographicExtent into the terrain cache. This method does not return until the terrain data is fully loaded. All terrain data within the extent is loaded into memory, even if doing so would exceed the TerrainCacheGroup's MaximumSize. Furthermore, the loaded terrain data is locked in memory (meaning it will not be unloaded) until the user calls UnloadExtent(CartographicExtent). This method is safe to call from any thread. (Overrides TerrainProviderPreloadExtent(CartographicExtent).)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	UnloadExtent	Unloads the cached terrain data for a given CartographicExtent. This method unloads all cached regions where any part of the region falls within the extent. It does not return until the regions have been unloaded. However, if a region within the extent is being used in another thread while this method is executing, the region may be reloaded immediately after this method unloads it. This method is safe to call from any thread. (Overrides TerrainProviderUnloadExtent(CartographicExtent).)

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Reference

AGI.Foundation.Terrain Namespace