Description
Finds the point on a feature line or boundary that is a given distance from the starting point on that feature.
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Return Type
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A Boolean value.
True if the given Distance from the start of the feature falls somewhere on the feature line or boundary. False is returned if the given Distance is beyond the end of the feature (for McPoints, False is always returned for any non-zero Distance, though using this method for an McPoints makes little sense).
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Syntax
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object.FeaturePointAtDistanceFromStart (Distance, FeatureIndex, AtDistanceX, AtDistanceY, AtDistVertexIndex, [CalibratedDistance])
The FeaturePointAtDistanceFromStart Method syntax has these parts: |
| object | An expression evaluating to an object of type McFeatures. | | Distance | Required. A Double value. The distance from the start of the feature for which the point is sought.
| | FeatureIndex | Required. A Long value. Which feature the point is to be computed for (zero by default).
| | AtDistanceX | Required. A Single value. and AtDistanceY results are always given in pixel coordinates, irrespective of the state of this argument.
| | AtDistanceY | Required. A Single value. Returned feature Y coordinate at the given distance. Or the last vertex Y of the feature if the given Distance is beyond the end (in this case the FeaturePointAtDistanceFromStart will return False).
| | AtDistVertexIndex | Required. A Long value. Returned index of the vertex at or beyond which the AtDistanceX/Y point was found. Note that for McRegions this may be the last vertex of the boundary, in which case the returned AtDistanceX/Y point will fall on the closing line segment joining the last boundary vertex to the first. Use the GetFeaturePoints method to retrieve the points associated with all vertices for a feature.
| | CalibratedDistance | Optional. A Boolean value. If True (the default) and the SpatialCalibration property is not Nothing, then the supplied distance must be in calibrated units. If False, then the supplied distance is in pixel units. Note that the
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Remarks
Given a distance, this method computes the point at that distance from the start of a given McLines feature line or the start of a given McRegions feature boundary. In addition, the index of the vertex of the segment on which the distance lies is returned. Should the given distance be beyond the end of the line or longer than the region boundary, then False is returned from this method.
The FeaturePointAtDistanceFromStart method can be useful for computing an edge point from the McProfileEdges.EdgeDistances property (though those points are also directly available via the McProfileEdges.EdgesAsMcPoints property
The reciprocal computation (that is given a vertex and a point, compute the distance along a line or boundary) is done by the DistanceToFeaturePoint method.
See PointClosestToPoint for an example using FeaturePointAtDistanceFromStart.
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FeaturePointAtDistanceFromStart Method (McFeatures)
