Create2DPolygon

The Create2DPolygon method creates a 2-dimensional polygon in the 3D window.

HRESULT Create2DPolygon (

[in, defaultvalue(0)] VARIANT SafeArrayVertices,

[in, defaultvalue(0x0000ff00)] long LineColor,

[in, defaultvalue(FT_NONE)] double FillOpacity,

[in, defaultvalue(0x00646464)] long FillColor,

[in, defaultvalue(HSC_TERRAIN_RELATIVE)] HeightStyleCode HeightStyle,

[in, defaultvalue(0)] long GroupID,

[in, defaultvalue("")] BSTR Description,

[out, retval] ITerrainPolyline5** pITerrainPolyline5)

Parameters:

• SafeArrayVertices – An array that contains triplets of doubles. Each triplet is composed of an x-coordinate, a height, and a y-coordinate. The COM interface represents the height in meters while the x- and y-coordinates are represented in MPT units. You can use the ITerrain interface to retrieve information about the MPT units. If you are working in a Lat-Long format, the Lat-Long values are given in decimal degrees. If this parameter is zero, the object manager creates an empty polyline to which the client can later add vertices.
  See:  “Creating a Polyline Using a Safe Array of Vertices”.

• LineColor – The color of the lines that make up the 2-dimensional polygon. The color value is used to specify an RGB color. When specifying an explicit RGB color, the color value has the following hexadecimal form: 0x00bbggrr. The low-order byte contains a value for the relative intensity of red; the second byte contains a value for green; and the third byte contains a value for blue. The high-order byte must be zero. The maximum value for a single byte is 0xFF.

• FillOpacity – Determines the degree of opacity or transparency of the fill of the 2-dimensional polygon. This value can be any value between 0, for transparent, and 1 for opaque.

• FillColor – The color with which the 2-dimensional polygon is filled if the FillOpacity value is greater than 0. The color value is used to specify an RGB color. When specifying an explicit RGB color, the color value has the following hexadecimal form: 0x00bbggrr. The low-order byte contains a value for the relative intensity of red; the second byte contains a value for green; and the third byte contains a value for blue. The high-order byte must be zero. The maximum value for a single byte is 0xFF.

• HeightStyle – An enum determining how the polygon is placed on the terrain.

The HeightStyleCode enum can use any of the following values:

• HSC_TERRAIN_RELATIVE = 0
  Each of the polygon’s vertices has a height relative to the terrain.

• HSC_PIVOT_RELATIVE  = 1
  Each of the vertices has a height relative to the polygon’s pivot.

• HSC_ON_TERRAIN = 2
  The vertices are placed on the terrain.

• HSC_TERRAIN_ABSOLUTE = 3
  Each of the polygon’s vertices has a height relative to the terrain database vertical datum base ellipsoid.

• GroupID – The Information Tree group in which the 2-dimensional polygon is created. If it is set to zero, the object is created under the root. You can obtain the GroupID by one of the following methods:

• Create the group the IInformationTree5::CreateGroup.

• If you know the name of the group, find it using IInformationTree5::FindItem.

• Traverse the Tree using IInformationTree5 methods such as GetNextItem, until you come to the desired GroupID.

• Description – The name of the 2-dimensional polygon as it appears in the Information Window. If an empty string is passed into this parameter, TerraExplorer assigns it a unique name.

• pITerrainPolyline5 – An interface pointer to the newly created 2-dimensional polygon. This parameter must not be Null.

Return Values:

The return value obtained from the returned HRESULT can be one of the following: