ArcGIS Pro 2.8 API Reference Guide
QueryPoint(Segment,SegmentExtension,Double,AsRatioOrLength) Method
Example 

ArcGIS.Core.Geometry Namespace > IGeometryEngine Interface > QueryPoint Method : QueryPoint(Segment,SegmentExtension,Double,AsRatioOrLength) Method
The segment on which the returned point lies.
Specifies the extension method.
The distance along the curve or the extended curve at which the returned point lies.
Determines whether the distanceAlongCurve is returned as a ratio of the segment length or as length from the start point.
Constructs a MapPointat a given distance along the curve or the extended curve.
Syntax

Parameters

segment
The segment on which the returned point lies.
extension
Specifies the extension method.
distanceAlongCurve
The distance along the curve or the extended curve at which the returned point lies.
asRatioOrLength
Determines whether the distanceAlongCurve is returned as a ratio of the segment length or as length from the start point.

Return Value

The point at the given distance along the curve or extended curve.
Exceptions
ExceptionDescription
segmentis null.
Spatial reference of segmentis an image coordinate system.
Remarks
If the distance is less than the length of the curve, then the returned point is the point at that distance along the curve. If the distance is less than zero, or greater than the length of the curve, then the returned point is on the curve specified by the extension method. The distance may be specified as a fixed unit of measure or a ratio of the length of the curve.
Example
SpatialReference sr = SpatialReferences.WGS84;

// Horizontal line segment
Coordinate2D start = new Coordinate2D(1, 1);
Coordinate2D end = new Coordinate2D(11, 1);
LineSegment line = LineBuilder.CreateLineSegment(start, end, sr);

Polyline polyline = PolylineBuilder.CreatePolyline(line);

// Don't extend the segment

MapPoint outPoint = GeometryEngine.Instance.QueryPoint(polyline, SegmentExtension.NoExtension, 1.0, AsRatioOrLength.AsLength);
// outPoint = (2, 1)

// or the segment
MapPoint outPoint_seg = GeometryEngine.Instance.QueryPoint(line, SegmentExtension.NoExtension, 1.0, AsRatioOrLength.AsLength);
// outPoint_seg = (2, 1)

// Extend infinitely in both directions
outPoint = GeometryEngine.Instance.QueryPoint(polyline, SegmentExtension.ExtendTangents, 1.5, AsRatioOrLength.AsRatio);
// outPoint = (16, 1)
outPoint_seg = GeometryEngine.Instance.QueryPoint(line, SegmentExtension.ExtendTangents, 1.5, AsRatioOrLength.AsRatio);
// outPoint_seg = (16, 1)
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

IGeometryEngine Interface
IGeometryEngine Members
Overload List