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TerrainProvider Class

The base class for all terrain providers. Terrain providers describe the surface of a central body by providing heights relative to an idealized ellipsoidal shape or relative to another terrain provider.
Inheritance Hierarchy

Namespace:  AGI.Foundation.Terrain
Assembly:  AGI.Foundation.Models (in AGI.Foundation.Models.dll) Version: 19.1.398.0 (19.1.398.0)
Syntax
public abstract class TerrainProvider

The TerrainProvider type exposes the following members.

Constructors
  NameDescription
Protected methodTerrainProvider
Initializes a new instance.
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Properties
  NameDescription
Public propertyBoundingExtent
Gets the smallest rectangular extent that bounds the terrain provided by this terrain provider. The returned extent's edges are expressed in radians.
Public propertyBoundingExtentNativeUnits
Gets 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.
Public propertyHeightReference
Gets an enumeration indicating whether the heights returned by the GetHeight(Double, Double) method are relative to the Shape or to the ReferenceSurface.
Public propertyMinimumSampleSpacing
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.
Public propertyNativeToMeters
Gets the value to multiply a height in the native units of the terrain provider to convert it to meters.
Public propertyRadiansToNative
Gets the value to multiply an angle in radians by in order to convert it to the internal units of the terrain provider.
Public propertyReferenceSurface
Gets the reference surface. The GetHeight(Double, Double) method returns heights relative to this reference surface. If this property is null, the heights are relative to the surface of the Shape ellipsoid instead.
Public propertyShape
Gets the shape on which the longitude and latitude are defined. If ReferenceSurface is null, the heights returned by GetHeight(Double, Double) are relative to this ellipsoid as well.
Public propertyShapeFixedFrame
Gets the reference frame fixed to the Shape in which the longitude and latitude are defined.
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Methods
  NameDescription
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetFirstPartials
Get the partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
Public methodGetGradient

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.

Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetHeight
Gets the interpolated height of the terrain at the specified longitude and latitude using the default interpolator for this terrain provider.
Public methodGetHeightNativeUnits
Gets the interpolated height of the terrain at the specified longitude and latitude.
Public methodGetHeightRelativeToShape
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.
Public methodGetHessian

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.

Public methodGetNormal
Get the normal vector to the terrain surface at the specified location.
Public methodGetSecondPartials
Get the second order (mixed) partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodPreloadExtent
Loads the terrain data in a given extent 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'sMaximumSize. 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.
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
Public methodUnloadExtent
Unloads the cached terrain data for a given extent. 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.
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See Also