CreateCircle

CreateCircle creates a circle in the 3D Window.

HRESULT CreateCircle (

[in] double X,

[in] double Y,

[in] double Elevation,

[in] double Radius,

[in, defaultvalue(12)] int NumOfSegments,

[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] ITerrainRegularPolygon5** pITerrainRegPolygon2)

Parameters:

• X – The West-East coordinate of the center of the circle represented in MPT units. You can use the ITerrain interface to retrieve information about the MPT units. If you are working in Lat-Long format, the Lat-Long values are in decimal Lat-Long.

• Y – The North-South coordinate of the center of the circle represented in MPT units. You can use the ITerrain interface to retrieve information about the MPT units. If you are working in Lat-Long format, the Lat-Long values are in decimal Lat-Long.

• Elevation – The elevation of the circle, which is interpreted using the HeightStyle parameter.

• Radius – The radius of the object (in meters).

• NumOfSegments – The number of segments the circle has. The more segments, the smoother and more circular it appears.

• LineColor – The color of the lines that make up the circle. 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 opacity or transparency of the fill of the circle. This value can be any value between 0, for transparent, and 1 for opaque.

• FillColor – The color with which the circle 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 circle is placed on the terrain.

The HeightStyleCode enum can use any of the following values:

• HSC_TERRAIN_RELATIVE = 0
  Each of the circle’s vertices has the same height above the terrain (determined by the Elevation parameter).

• HSC_PIVOT_RELATIVE = 1
  The height of the circle’s pivot (the center of the circle) is determined by the Elevation parameter. Each of the circle’s vertices lies on the same plane as the circle’s pivot.

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

• HSC_TERRAIN_ABSOLUTE = 3
  The height relative to the terrain database vertical datum base ellipsoid of the circle’s pivot (the center of the circle) is determined by the Elevation parameter. Each of the circle’s vertices lies on the same plane as the circle’s pivot.

• GroupID – The Information Tree group in which the regular polygon is created. If it is set to zero, the regular polygon 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 regular polygon as it appears in the Information Window. If an empty string is passed into this parameter, TerraExplorer assigns it a unique name.

• PITerrainRegularPolygon5 – An interface pointer to the newly created regular polygon. This parameter must not be Null.

Return Values:

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

Remarks:

The CreateCircle() method is essentially the same as CreateRegularPolygon(). The only difference between the two is the fact that the CreateCircle() method has 12 segments as its default number of segments.