Crs.Length Methods
Returns the horizontal length of a line.
Overload List
| Name | Description | |
|---|---|---|
| Public method | Length(PointCollection line, LineType lineType, System.Boolean lineClosed) | Returns the horizontal length of the line represented by the specified points. |
| Public method | Length(Point start, Point end, LineType lineType) | Returns the horizontal length of a line segment between two specified points. |
| Public method | Length(IEnumerable< Point > line, LineType lineType, System.Boolean lineClosed) | Returns the horizontal length of the line represented by the specified points. |
Length(PointCollection line, LineType lineType, System.Boolean lineClosed)
Returns the horizontal length of the line represented by the specified points.Syntax
public System.Double Length (
PointCollection line,
LineType lineType,
System.Boolean lineClosed
)Parameters
The polyline, as a collection of projected points.
The kind of line.
Whether there is a line segment from the last point back to the first.
Return Value
The horizontal and sea-level length (the z-values are ignored) of the line, in meters.
Remarks
Line type and accuracy
The supported line types are GreatCircle, GreatCircleApprox and RhumbLine, so the straight 3D line type is not supported. However, if the Projection is a NonGeoreferencedProjection, then the line segments are regarded as straight lines in the plane, with unknown accuracy on Earth. Otherwise, the points are unprojected to LongLat before the length is computed from the longitudes and latitudes. The error bounds below do not include errors that may be caused by UnprojectToLongLat.
RhumbLine
The line segments are regarded as curves of constant azimuth, known as rhumb lines or loxodromes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircle
The line segments are regarded as great-circle segments, also known as shortest routes or geodesic routes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircleApprox
The line segments are regarded as great-circle segments. But the Earth is modelled as a sphere, with a local compensation used for the flattening of the earth, which means that the accuracy is best for short line segments. The following error bounds hold for each line segment:
line-segment length up to | max error |
|---|---|
100 km | 0.0017 % (1.7 m) |
300 km | 0.0019 % (5.7 m) |
1 000 km | 0.0031 % (31 m) |
3 000 km | 0.014 % (420 m) |
10 000 km | 0.11 % (11 km) |
15 000 km | 0.17 % (26 km) |
20 004 km (antipodes) | 0.18 % (36 km) |
Speed
If the projection is already LongLat, then the computation time for GreatCircle will normally be about 2.4 times longer than for GreatCircleApprox.
Length(Point start, Point end, LineType lineType)
Returns the horizontal length of a line segment between two specified points.Syntax
public System.Double Length (
Point start,
Point end,
LineType lineType
)Parameters
The first point in the segment.
The last point in the segment.
The kind of line segment.
Return Value
The horizontal and sea-level length (the z-values are ignored) of the line segment, in meters.
Remarks
Line type and accuracy
The supported line types are GreatCircle, GreatCircleApprox and RhumbLine, so the straight 3D line type is not supported. However, if the Projection is a NonGeoreferencedProjection, then the line segments are regarded as straight lines in the plane, with unknown accuracy on Earth. Otherwise, the points are unprojected to LongLat before the length is computed from the longitudes and latitudes. The error bounds below do not include errors that may be caused by UnprojectToLongLat.
RhumbLine
The line segments are regarded as curves of constant azimuth, known as rhumb lines or loxodromes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircle
The line segments are regarded as great-circle segments, also known as shortest routes or geodesic routes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircleApprox
The line segments are regarded as great-circle segments. But the Earth is modelled as a sphere, with a local compensation used for the flattening of the earth, which means that the accuracy is best for short line segments. The following error bounds hold for each line segment:
line-segment length up to | max error |
|---|---|
100 km | 0.0017 % (1.7 m) |
300 km | 0.0019 % (5.7 m) |
1 000 km | 0.0031 % (31 m) |
3 000 km | 0.014 % (420 m) |
10 000 km | 0.11 % (11 km) |
15 000 km | 0.17 % (26 km) |
20 004 km (antipodes) | 0.18 % (36 km) |
Speed
If the projection is already LongLat, then the computation time for GreatCircle will normally be about 2.4 times longer than for GreatCircleApprox.
Length(IEnumerable< Point > line, LineType lineType, System.Boolean lineClosed)
Returns the horizontal length of the line represented by the specified points.Syntax
public System.Double Length (
IEnumerable< Point > line,
LineType lineType,
System.Boolean lineClosed
)Parameters
The polyline, as a collection of projected points.
The kind of line.
Whether there is a line segment from the last point back to the first.
Return Value
The horizontal and sea-level length (the z-values are ignored) of the line, in meters.
Remarks
Line type and accuracy
The supported line types are GreatCircle, GreatCircleApprox and RhumbLine, so the straight 3D line type is not supported. However, if the Projection is a NonGeoreferencedProjection, then the line segments are regarded as straight lines in the plane, with unknown accuracy on Earth. Otherwise, the points are unprojected to LongLat before the length is computed from the longitudes and latitudes. The error bounds below do not include errors that may be caused by UnprojectToLongLat.
RhumbLine
The line segments are regarded as curves of constant azimuth, known as rhumb lines or loxodromes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircle
The line segments are regarded as great-circle segments, also known as shortest routes or geodesic routes. The Earth is modelled as an ellipsoid, and the method accuracy is 1 millimeter per line segment.
GreatCircleApprox
The line segments are regarded as great-circle segments. But the Earth is modelled as a sphere, with a local compensation used for the flattening of the earth, which means that the accuracy is best for short line segments. The following error bounds hold for each line segment:
line-segment length up to | max error |
|---|---|
100 km | 0.0017 % (1.7 m) |
300 km | 0.0019 % (5.7 m) |
1 000 km | 0.0031 % (31 m) |
3 000 km | 0.014 % (420 m) |
10 000 km | 0.11 % (11 km) |
15 000 km | 0.17 % (26 km) |
20 004 km (antipodes) | 0.18 % (36 km) |
Speed
If the projection is already LongLat, then the computation time for GreatCircle will normally be about 2.4 times longer than for GreatCircleApprox.
Platforms
Windows, Linux, Android