Format
SDO_UTIL.ELLIPSE_POLYGON(
center_longitude IN NUMBER,
center_latitude IN NUMBER,
semi_major_axis IN NUMBER,
semi_minor_axis IN NUMBER,
azimuth IN NUMBER,
arc_tolerance IN NUMBER
) RETURN SDO_GEOMETRY;Description
Returns the polygon geometry that approximates and is covered by a specified ellipse.
Parameters
Center longitude (in degrees) of the ellipse to be used to create the returned geometry.
Center latitude (in degrees) of the ellipse to be used to create the returned geometry.
Length (in meters) of the semi-major axis of the ellipse to be used to create the returned geometry.
Length (in meters) of the semi-minor axis of the ellipse to be used to create the returned geometry.
Number of degrees of the azimuth (clockwise rotation of the major axis from north) of the ellipse to be used to create the returned geometry. Must be from 0 to 180. The returned geometry is rotated by the specified number of degrees.
A numeric value to be used to construct the polygon geometry. The arc_tolerance parameter value has the same meaning and usage guidelines as the arc_tolerance keyword value in the params parameter string for the SDO_GEOM.SDO_ARC_DENSIFY function. The unit of measurement associated with the geometry is associated with the arc_tolerance parameter value. (For more information, see the Usage Notes for the SDO_GEOM.SDO_ARC_DENSIFY function in SDO_GEOM Package (Geometry).)
Usage Notes
This function is useful for creating an ellipse-like polygon around a specified center point when a true ellipse cannot be used (an ellipse is not valid for geodetic data with Oracle Spatial and Graph). The returned geometry has an SDO_SRID value of 8307 (for Longitude / Latitude (WGS 84)).
Examples
The following example returns an ellipse-like polygon, oriented east-west (azimuth = 90), around a point near the center of Concord, Massachusetts. An arc_tolerance value of 5 meters is used in computing the polygon vertices.
SELECT SDO_UTIL.ELLIPSE_POLYGON(-71.34937, 42.46101, 100, 50, 90, 5) FROM DUAL; SDO_UTIL.ELLIPSE_POLYGON(-71.34937,42.46101,100,50,90,5)(SDO_GTYPE, SDO_SRID, SD -------------------------------------------------------------------------------- SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1), SDO_ORDINATE_ARR AY(-71.350589, 42.46101, -71.350168, 42.4606701, -71.349708, 42.460578, -71.3493 7, 42.4605603, -71.349032, 42.460578, -71.348572, 42.4606701, -71.348151, 42.461 01, -71.348572, 42.4613499, -71.349032, 42.461442, -71.34937, 42.4614597, -71.34 9708, 42.461442, -71.350168, 42.4613499, -71.350589, 42.46101))
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