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Attributes
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Facets
Instances
Properties
Source
Used by
Element gml:BezierType / gml:degree
Namespace http://www.opengis.net/gml
Annotations
The attribute "degree" shall be the degree of the polynomial used for interpolation in this spline.
Diagram
Diagram
Type nonNegativeInteger
Properties
content: simple
Source
<element name="degree" type="nonNegativeInteger">
  <annotation>
    <documentation>The attribute "degree" shall be the degree of the polynomial used for interpolation in this spline.</documentation>
  </annotation>
</element>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Element gml:BezierType / gml:knot
Namespace http://www.opengis.net/gml
Annotations
The property "knot" shall be the sequence of distinct knots used to define the spline basis functions.
Diagram
Diagram docindex116.tmp#id615 docindex116.tmp#id614
Type gml:KnotPropertyType
Properties
content: complex
minOccurs: 2
maxOccurs: 2
Model gml:Knot
Children gml:Knot
Instance
<gml:knot>
  <gml:Knot>{1,1}</gml:Knot>
</gml:knot>
Source
<element name="knot" type="gml:KnotPropertyType" minOccurs="2" maxOccurs="2">
  <annotation>
    <documentation>The property "knot" shall be the sequence of distinct knots used to define the spline basis functions.</documentation>
  </annotation>
</element>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Complex Type gml:BezierType
Namespace http://www.opengis.net/gml
Annotations
Bezier curves are polynomial splines that use Bezier or Bernstein polynomials for interpolation purposes. It is a special case of the B-Spline curve with two knots.
Diagram
Diagram docindex129.tmp#id557 docindex129.tmp#id558 docindex129.tmp#id559 docindex129.tmp#id556 docindex231.tmp#id619 docindex231.tmp#id620 docindex231.tmp#id621 docindex131.tmp#id74 docindex132.tmp#id177 docindex133.tmp#id372 docindex134.tmp#id181 docindex135.tmp#id75 docindex231.tmp#id617 docindex231.tmp#id618 docindex231.tmp#id616 docindex298.tmp#id626 docindex298.tmp#id627 docindex298.tmp#id628 docindex131.tmp#id74 docindex132.tmp#id177 docindex133.tmp#id372 docindex134.tmp#id181 docindex135.tmp#id75 docindex298.tmp#id624 docindex298.tmp#id625
Type restriction of gml:BSplineType
Type hierarchy
Used by
Element gml:Bezier
Model (gml:pos | gml:pointProperty | gml:pointRep | gml:posList | gml:coordinates) , gml:degree , gml:knot{2,2}
Children gml:coordinates, gml:degree, gml:knot, gml:pointProperty, gml:pointRep, gml:pos, gml:posList
Attributes
QName Type Fixed Default Use Annotation
interpolation gml:CurveInterpolationType polynomialSpline 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 a Bezier the interpolation is fixed as "polynomialSpline".
isPolynomial boolean true optional
The attribute isPolynomial is set to true as this is a polynomial spline.
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="BezierType">
  <annotation>
    <documentation>Bezier curves are polynomial splines that use Bezier or Bernstein polynomials for interpolation purposes. It is a special case of the B-Spline curve with two knots.</documentation>
  </annotation>
  <complexContent>
    <restriction base="gml:BSplineType">
      <sequence>
        <choice>
          <annotation>
            <documentation>GML supports two different ways to specify the control points of a curve segment. 1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points). 2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only.</documentation>
          </annotation>
          <choice minOccurs="0" maxOccurs="unbounded">
            <element ref="gml:pos"/>
            <element ref="gml:pointProperty"/>
            <element ref="gml:pointRep">
              <annotation>
                <documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
              </annotation>
            </element>
          </choice>
          <element ref="gml:posList"/>
          <element ref="gml:coordinates">
            <annotation>
              <documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
            </annotation>
          </element>
        </choice>
        <element name="degree" type="nonNegativeInteger">
          <annotation>
            <documentation>The attribute "degree" shall be the degree of the polynomial used for interpolation in this spline.</documentation>
          </annotation>
        </element>
        <element name="knot" type="gml:KnotPropertyType" minOccurs="2" maxOccurs="2">
          <annotation>
            <documentation>The property "knot" shall be the sequence of distinct knots used to define the spline basis functions.</documentation>
          </annotation>
        </element>
      </sequence>
      <attribute name="interpolation" type="gml:CurveInterpolationType" fixed="polynomialSpline">
        <annotation>
          <documentation>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 a Bezier the interpolation is fixed as "polynomialSpline".</documentation>
        </annotation>
      </attribute>
      <attribute name="isPolynomial" type="boolean" fixed="true">
        <annotation>
          <documentation>The attribute isPolynomial is set to true as this is a polynomial spline.</documentation>
        </annotation>
      </attribute>
      <attribute name="knotType" type="gml:KnotTypesType" use="prohibited">
        <annotation>
          <documentation>The property "knotType" is not relevant for Bezier curve segments.</documentation>
        </annotation>
      </attribute>
    </restriction>
  </complexContent>
</complexType>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Attribute gml:BezierType / @interpolation
Namespace No namespace
Annotations
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 a Bezier the interpolation is fixed as "polynomialSpline".
Type gml:CurveInterpolationType
Properties
fixed: polynomialSpline
Facets
enumeration linear
enumeration geodesic
enumeration circularArc3Points
enumeration circularArc2PointWithBulge
enumeration circularArcCenterPointWithRadius
enumeration elliptical
enumeration clothoid
enumeration conic
enumeration polynomialSpline
enumeration cubicSpline
enumeration rationalSpline
Used by
Complex Type gml:BezierType
Source
<attribute name="interpolation" type="gml:CurveInterpolationType" fixed="polynomialSpline">
  <annotation>
    <documentation>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 a Bezier the interpolation is fixed as "polynomialSpline".</documentation>
  </annotation>
</attribute>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Attribute gml:BezierType / @isPolynomial
Namespace No namespace
Annotations
The attribute isPolynomial is set to true as this is a polynomial spline.
Type boolean
Properties
fixed: true
Used by
Complex Type gml:BezierType
Source
<attribute name="isPolynomial" type="boolean" fixed="true">
  <annotation>
    <documentation>The attribute isPolynomial is set to true as this is a polynomial spline.</documentation>
  </annotation>
</attribute>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Attribute gml:BezierType / @knotType
Namespace No namespace
Annotations
The property "knotType" is not relevant for Bezier curve segments.
Type gml:KnotTypesType
Properties
use: prohibited
Facets
enumeration uniform
enumeration quasiUniform
enumeration piecewiseBezier
Used by
Complex Type gml:BezierType
Source
<attribute name="knotType" type="gml:KnotTypesType" use="prohibited">
  <annotation>
    <documentation>The property "knotType" is not relevant for Bezier curve segments.</documentation>
  </annotation>
</attribute>
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd