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Annotations
Attributes
Diagrams
Source
Used by
Complex Type gml:CircleType
Namespace http://www.opengis.net/gml
Annotations
A Circle is an arc whose ends coincide to form a simple closed loop. The "start" and "end" bearing are equal and shall be the bearing for the first controlPoint listed. The three control points must be distinct non-co-linear points for the Circle to be unambiguously defined. The arc is simply extended past the third control point until the first control point is encountered.
Diagram
Diagram index59.tmp#id583 index59.tmp#id584 index59.tmp#id585 index59.tmp#id582 index103.tmp#id592 index103.tmp#id593 index61.tmp#id70 index62.tmp#id175 index63.tmp#id216 index64.tmp#id179 index65.tmp#id71 index103.tmp#id591 index236.tmp#id595 index61.tmp#id70 index62.tmp#id175 index63.tmp#id216 index64.tmp#id179 index65.tmp#id71 index236.tmp#id594
Type extension of gml:ArcType
Type hierarchy
Used by
Element gml:Circle
Model (gml:pos | gml:pointProperty | gml:pointRep | gml:posList | gml:coordinates)
Children gml:coordinates, gml:pointProperty, gml:pointRep, gml:pos, gml:posList
Attributes
QName Type Fixed Default Use Annotation
interpolation gml:CurveInterpolationType circularArc3Points optional
The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism uses the control points and control parameters to determine the position of this curve segment. For an ArcString the interpolation is fixed as "circularArc3Points".
numArc integer 1 optional
An arc is an arc string consiting of a single arc, the attribute is fixed to "1".
numDerivativeInterior integer 0 optional
The attribute "numDerivativesInterior" specifies the type of continuity that is guaranteed interior to the curve. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity. NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.
numDerivativesAtEnd integer 0 optional
The attribute "numDerivativesAtEnd" specifies the type of continuity between this curve segment and its successor. If this is the last curve segment in the curve, one of these values, as appropriate, is ignored. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity. NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.
numDerivativesAtStart integer 0 optional
The attribute "numDerivativesAtStart" specifies the type of continuity between this curve segment and its predecessor. If this is the first curve segment in the curve, one of these values, as appropriate, is ignored. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity. NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.
Source
<complexType name="CircleType">
  <annotation>
    <documentation>A Circle is an arc whose ends coincide to form a simple closed loop. The "start" and "end" bearing are equal and shall be the bearing for the first controlPoint listed. The three control points must be distinct non-co-linear points for the Circle to be unambiguously defined. The arc is simply extended past the third control point until the first control point is encountered.</documentation>
  </annotation>
  <complexContent>
    <extension base="gml:ArcType"/>
  </complexContent>
</complexType>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd