gml:BSpline

A B-Spline is a piecewise parametric polynomial or rational curve described in terms of control points and basis functions as specified in ISO 19107:2003, 6.4.30. Therefore, interpolation may be either "polynomialSpline" or "rationalSpline" depending on the interpolation type; default is "polynomialSpline".
degree shall be the degree of the polynomial used for interpolation in this spline.
knot shall be the sequence of distinct knots used to define the spline basis functions (see ISO 19107:2003, 6.4.26.2).
The attribute isPolynomial shall be set to "true" if this is a polynomial spline (see ISO 19107:2003, 6.4.30.5).
The attribute knotType shall provide the type of knot distribution used in defining this spline (see ISO 19107:2003, 6.4.30.4).
The content model follows the general pattern for the encoding of curve segments.

Element information

Content

• Sequence [1..1]
  1. Choice [1..1]
     • Choice [0..*]
       • gml:pos    
       • gml:pointProperty    This property element either references a point via the XLink-attributes or contains the point element. pointProperty is the predefined property which may be used by GML Application Schemas whenever a GML feature has a property with a value that is substitutable for Point.
       • gml:pointRep    deprecated
     • gml:posList    
     • gml:coordinates    deprecated
  2. gml:degree [1..1]    
  3. gml:knot [2..*]    

Attributes

Used in

• Type gml:ArrayAssociationType (Element gml:members)
• Type gml:CurveSegmentArrayPropertyType (Element gml:segments)

Substitution hierarchy

• gml:AbstractObject
  • can be substituted with gml:AbstractCurveSegment
    • can be substituted with gml:BSpline
      • can be substituted with gml:Bezier

Sample instance

<gml:BSpline>
   <gml:pos>1.0 1.0</gml:pos>
   <gml:degree>1</gml:degree>
   <gml:knot>
      <gml:Knot>
         <gml:value>1.0</gml:value>
         <gml:multiplicity>1</gml:multiplicity>
         <gml:weight>1.0</gml:weight>
      </gml:Knot>
   </gml:knot>
</gml:BSpline>