Click or drag to resize

NgaDigitalTerrainElevationDataCell Class

A terrain provider for reading terrain from a single 1 degree x 1 degree cell of a National Geospatial-Intelligence Agency (NGA) Digital Terrain Elevation Data (DTED) file.
Inheritance Hierarchy

Namespace:  AGI.Foundation.Terrain
Assembly:  AGI.Foundation.TerrainReaders (in AGI.Foundation.TerrainReaders.dll) Version: 24.2.419.0 (24.2.419.0)
Syntax
public class NgaDigitalTerrainElevationDataCell : RasterTerrainProvider

The NgaDigitalTerrainElevationDataCell type exposes the following members.

Constructors
  NameDescription
Public methodNgaDigitalTerrainElevationDataCell(StreamFactory)
Initializes a new instance with the specified stream factory.
Public methodNgaDigitalTerrainElevationDataCell(String)
Initializes a new instance using the specified filename.
Public methodNgaDigitalTerrainElevationDataCell(StreamFactory, TerrainCacheGroup)
Initializes a new instance with the specified stream factory.
Public methodNgaDigitalTerrainElevationDataCell(String, TerrainCacheGroup)
Initializes a new instance using the specified filename.
Top
Properties
  NameDescription
Public propertyBoundingExtent
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.)
Public propertyBoundingExtentNativeUnits
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.)
Public propertyCache
Gets the cache for this terrain provider.
(Inherited from RasterTerrainProvider.)
Public propertyDefaultInterpolator
Gets or sets the default interpolator to use to interpolate heights when a specific interpolator is not specified in the call to GetHeight(Double, Double) or GetHeightNativeUnits(Double, Double).
(Inherited from RasterTerrainProvider.)
Public propertyDeltaLatitude
Gets or sets the distance between each post in the latitude direction, in radians.
(Inherited from RasterTerrainProvider.)
Public propertyDeltaLatitudeNativeUnits
Gets or sets the distance between each post in the latitude direction, in the native units of the provider.
(Inherited from RasterTerrainProvider.)
Public propertyDeltaLongitude
Gets or sets the distance between each post in the longitude direction, in radians.
(Inherited from RasterTerrainProvider.)
Public propertyDeltaLongitudeNativeUnits
Gets or sets the distance between each post in the longitude direction, in the native units of the provider.
(Inherited from RasterTerrainProvider.)
Public propertyEasternPostOffsetNativeUnits
Gets or sets the longitude offset (from the east) of the eastern-most post in the terrain provider.
(Inherited from RasterTerrainProvider.)
Public propertyHeightReference
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.)
Public propertyLatitudePosts
Gets or sets the number of posts in the latitude direction.
(Inherited from RasterTerrainProvider.)
Public propertyLongitudePosts
Gets or sets the number of posts in the longitude direction.
(Inherited from RasterTerrainProvider.)
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.
(Inherited from RasterTerrainProvider.)
Public propertyNativeToMeters
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.)
Protected propertyNeedsSpecialCoordinateProcessing
Gets or sets a value indicating whether or not special processing of longitude and latitude coordinates is required by this terrain provider. If this value is , GetHeightNativeUnits(Double, Double, RasterTerrainInterpolator) will call ProcessCoordinates(Double, Double) before using the coordinates to load sets of posts or interpolate heights.
(Inherited from RasterTerrainProvider.)
Public propertyNorthernPostOffsetNativeUnits
Gets or sets the latitude offset (from the north) of the northern-most post in the terrain provider.
(Inherited from RasterTerrainProvider.)
Public propertyRadiansToNative
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.)
Public propertyReferenceSurface
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.)
Public propertyShape
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.)
Public propertyShapeFixedFrame
Gets or sets the reference frame fixed to the Shape in which the longitude and latitude are defined.
(Inherited from TerrainProvider.)
Public propertySouthernPostOffsetNativeUnits
Gets or sets the latitude offset (toward the north) of the southern-most post in the terrain provider.
(Inherited from RasterTerrainProvider.)
Public propertyWesternPostOffsetNativeUnits
Gets or sets the longitude offset (toward the east) of the western-most post in the terrain provider.
(Inherited from RasterTerrainProvider.)
Top
Methods
  NameDescription
Public methodCartographicExtentToIndexExtent
Gets the post indices corresponding to a given cartographic extent.
(Inherited from RasterTerrainProvider.)
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(Double, Double)
Get the partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
(Inherited from RasterTerrainProvider.)
Public methodGetFirstPartials(Double, Double, RasterTerrainInterpolator)
Get the interpolated partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
(Inherited from RasterTerrainProvider.)
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.

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

(Inherited from TerrainProvider.)
Public methodGetLocalMinimumSampleSpacing
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.)
Public methodGetNormal
Get the normal vector to the terrain surface at the specified location.
(Inherited from TerrainProvider.)
Public methodGetPosts
Gets the posts over a specified area by reading them from the terrain data source. This method is not expected to do any caching.
(Overrides RasterTerrainProviderGetPosts(RasterTerrainIndexExtent).)
Public methodGetSecondPartials(Double, Double)
Get the second order (mixed) partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
(Inherited from RasterTerrainProvider.)
Public methodGetSecondPartials(Double, Double, RasterTerrainInterpolator)
Get the second order (mixed) partial derivatives of height with respect to the specified longitude and latitude relative to the provider's Shape.
(Inherited from RasterTerrainProvider.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodIndexToLatitude
Gets the latitude, in native units, of the post at a specified index.
(Inherited from RasterTerrainProvider.)
Public methodIndexToLongitude
Gets the longitude, in native units, of the post at a specified index.
(Inherited from RasterTerrainProvider.)
Protected methodInGlobalBounds
Returns if the coordinates are in global bounds which is: [-π, π] for longitude and [-π/2, π/2] for latitude.
(Inherited from TerrainProvider.)
Public methodLatitudeToIndex
Gets the index of the post at or immediately to the south of the specified latitude.
(Inherited from RasterTerrainProvider.)
Public methodLongitudeToIndex
Gets the index of the post at or immediately to the west of the specified longitude.
(Inherited from RasterTerrainProvider.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodPreloadExtent
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'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.
(Inherited from RasterTerrainProvider.)
Protected methodProcessCoordinates
Performs any additional processing of coordinate values prior to using them to load sets of posts or for interpolating heights. This method is only called if NeedsSpecialCoordinateProcessing is .
(Inherited from RasterTerrainProvider.)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
Public methodUnloadExtent
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.
(Inherited from RasterTerrainProvider.)
Top
See Also