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 Annotations Attributes Diagrams Facets Properties Source Used by
Complex Type gml:ArcStringType
Namespace http://www.opengis.net/gml
Annotations
 `An ArcString is a curve segment that uses three-point circular arc interpolation.`
Diagram Type extension of gml:AbstractCurveSegmentType
Type hierarchy
Used by
 Element gml:ArcString Complex Type gml:ArcType
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 optional
 `The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be 2 * numArc + 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
 ``` An ArcString is a curve segment that uses three-point circular arc interpolation. 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. The number of direct positions in the list must be at least three. Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0. Deprecated with GML version 3.1.0. Use "posList" instead. 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". The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be 2 * numArc + 1. ```
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Attribute gml:ArcStringType / @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 an ArcString the interpolation is fixed as "circularArc3Points".```
Type gml:CurveInterpolationType
Properties
 fixed: circularArc3Points
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:ArcStringType
Source
 ``` 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". ```
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd
Attribute gml:ArcStringType / @numArc
Namespace No namespace
Annotations
 `The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be 2 * numArc + 1.`
Type integer
Properties
 use: optional
Used by
 Complex Type gml:ArcStringType
Source
 ``` The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be 2 * numArc + 1. ```
Schema location http://schemas.opengis.net/gml/3.1.1/base/geometryPrimitives.xsd