#include <LocationIndexedLine.h>
Public Member Functions | |
LocationIndexedLine (const geom::Geometry *linearGeom) | |
Constructs an object which allows linear referencing along a given linear Geometry. | |
geom::Coordinate | extractPoint (const LinearLocation &index) const |
Computes the Coordinate for the point on the line at the given index. | |
geom::Coordinate | extractPoint (const LinearLocation &index, double offsetDistance) const |
Computes the Coordinate for the point on the line at the given index, offset by the given distance. | |
geom::Geometry * | extractLine (const LinearLocation &startIndex, const LinearLocation &endIndex) const |
Computes the LineString for the interval on the line between the given indices. | |
LinearLocation | indexOf (const geom::Coordinate &pt) const |
Computes the index for a given point on the line. | |
LinearLocation | indexOfAfter (const geom::Coordinate &pt, const LinearLocation &minIndex) const |
Finds the index for a point on the line which is greater than the given index. | |
LinearLocation * | indicesOf (const geom::Geometry *subLine) const |
Computes the indices for a subline of the line. | |
LinearLocation | project (const geom::Coordinate &pt) const |
Computes the index for the closest point on the line to the given point. | |
LinearLocation | getStartIndex () const |
Returns the index of the start of the line. | |
LinearLocation | getEndIndex () const |
Returns the index of the end of the line. | |
bool | isValidIndex (const LinearLocation &index) const |
Tests whether an index is in the valid index range for the line. | |
LinearLocation | clampIndex (const LinearLocation &index) const |
Computes a valid index for this line by clamping the given index to the valid range of index values. |
geos::linearref::LocationIndexedLine::LocationIndexedLine | ( | const geom::Geometry * | linearGeom | ) | [inline] |
Constructs an object which allows linear referencing along a given linear Geometry.
linearGeom | the linear geometry to reference along |
LinearLocation geos::linearref::LocationIndexedLine::clampIndex | ( | const LinearLocation & | index | ) | const [inline] |
Computes a valid index for this line by clamping the given index to the valid range of index values.
geom::Geometry* geos::linearref::LocationIndexedLine::extractLine | ( | const LinearLocation & | startIndex, | |
const LinearLocation & | endIndex | |||
) | const [inline] |
Computes the LineString for the interval on the line between the given indices.
If the endIndex lies before the startIndex, the computed geometry is reversed.
startIndex | the index of the start of the interval | |
endIndex | the index of the end of the interval |
geom::Coordinate geos::linearref::LocationIndexedLine::extractPoint | ( | const LinearLocation & | index, | |
double | offsetDistance | |||
) | const [inline] |
Computes the Coordinate for the point on the line at the given index, offset by the given distance.
If the index is out of range the first or last point on the line will be returned. The computed point is offset to the left of the line if the offset distance is positive, to the right if negative.
The Z-ordinate of the computed point will be interpolated from the Z-ordinates of the line segment containing it, if they exist.
index | the index of the desired point | |
offsetDistance | the distance the point is offset from the segment (positive is to the left, negative is to the right) |
geom::Coordinate geos::linearref::LocationIndexedLine::extractPoint | ( | const LinearLocation & | index | ) | const [inline] |
Computes the Coordinate for the point on the line at the given index.
If the index is out of range the first or last point on the line will be returned. The Z-ordinate of the computed point will be interpolated from the Z-ordinates of the line segment containing it, if they exist.
index | the index of the desired point |
LinearLocation geos::linearref::LocationIndexedLine::getEndIndex | ( | ) | const [inline] |
Returns the index of the end of the line.
LinearLocation geos::linearref::LocationIndexedLine::getStartIndex | ( | ) | const [inline] |
Returns the index of the start of the line.
LinearLocation geos::linearref::LocationIndexedLine::indexOf | ( | const geom::Coordinate & | pt | ) | const [inline] |
Computes the index for a given point on the line.
The supplied point does not necessarily have to lie precisely on the line, but if it is far from the line the accuracy and performance of this function is not guaranteed. Use project to compute a guaranteed result for points which may be far from the line.
pt | a point on the line |
LinearLocation geos::linearref::LocationIndexedLine::indexOfAfter | ( | const geom::Coordinate & | pt, | |
const LinearLocation & | minIndex | |||
) | const [inline] |
Finds the index for a point on the line which is greater than the given index.
If no such index exists, returns minIndex
. This method can be used to determine all indexes for a point which occurs more than once on a non-simple line. It can also be used to disambiguate cases where the given point lies slightly off the line and is equidistant from two different points on the line.
The supplied point does not necessarily have to lie precisely on the line, but if it is far from the line the accuracy and performance of this function is not guaranteed. Use project to compute a guaranteed result for points which may be far from the line.
pt | a point on the line | |
minIndex | the value the returned index must be greater than |
LinearLocation* geos::linearref::LocationIndexedLine::indicesOf | ( | const geom::Geometry * | subLine | ) | const [inline] |
Computes the indices for a subline of the line.
(The subline must conform to the line; that is, all vertices in the subline (except possibly the first and last) must be vertices of the line and occur in the same order).
subLine | a subLine of the line |
bool geos::linearref::LocationIndexedLine::isValidIndex | ( | const LinearLocation & | index | ) | const [inline] |
Tests whether an index is in the valid index range for the line.
length | the index to test |
true
if the index is in the valid range LinearLocation geos::linearref::LocationIndexedLine::project | ( | const geom::Coordinate & | pt | ) | const [inline] |
Computes the index for the closest point on the line to the given point.
If more than one point has the closest distance the first one along the line is returned. (The point does not necessarily have to lie precisely on the line.)
pt | a point on the line |