Position class abstract

A base interface for geospatial positions.

The known sub classes are Projected (with x, y, z and m coordinates) and Geographic (with lon, lat, elev and m coordinates).

All implementations must contain at least x and y coordinate values, but z and m coordinates are optional (getters should return zero value when such a coordinate axis is not available).

When a position contains geographic coordinates, then by default x represents longitude, y represents latitude, and z represents elevation (or height or altitude).

A projected map position might be defined as easting (E) and northing (N) coordinates. It's suggested that then E == x and N == y, but a coordinate reference system might specify something else too.

m represents a measurement or a value on a linear referencing system (like time). It could be associated with a 2D position (x, y, m) or a 3D position (x, y, z, m).

For 2D coordinates the coordinate axis indexes are:

Index	Projected	Geographic
0	x	lon
1	y	lat
2	m	m

For 3D coordinates the coordinate axis indexes are:

Index	Projected	Geographic
0	x	lon
1	y	lat
2	z	elev
3	m	m

Sub classes containing coordinate values mentioned above, should implement equality and hashCode methods as:

@override
bool operator ==(Object other) =>
     other is Position && Position.testEquals(this, other);

@override
int get hashCode => Position.hash(this);

Implementers

Constructors

Position(): Default const constructor to allow extending this abstract class.
const

Properties

coordinateDimension → int: The number of coordinate values (2, 3 or 4).
no setterinherited
hashCode → int: The hash code for this object.
no setterinherited
is3D → bool: True for 3D positions (with z or elevation coordinate).
no setterinherited
isMeasured → bool: True if a measure value is available (or the m coordinate for a position).
no setterinherited
m → num: The m ("measure") coordinate value. Returns zero if not available.
no setter
optM → num?: The m ("measure") coordinate optionally. Returns null if not available.
no setter
optZ → num?: The z coordinate value optionally. Returns null if not available.
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
spatialDimension → int: The number of spatial coordinate values (2 for 2D or 3 for 3D).
no setterinherited
type → Coords: The coordinate type.
no setterinherited
values → Iterable<num>: Coordinate values of this position as an iterable of 2, 3 or 4 items.
no setter
x → num: The x coordinate value.
no setter
y → num: The y coordinate value.
no setter
z → num: The z coordinate value. Returns zero if not available.
no setter

Methods

copyTo<R extends Position>(CreatePosition<R> factory) → R: Copies this position to a new position created by the factory.
copyWith({num? x, num? y, num? z, num? m}) → Position: Copies the position with optional x, y, z and m overriding values.
equals2D(Position other, {num? toleranceHoriz}) → bool: True if this position equals with other by testing 2D coordinates only.
equals3D(Position other, {num? toleranceHoriz, num? toleranceVert}) → bool: True if this position equals with other by testing 3D coordinates only.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
toString() → String: A string representation of this object.
override
transform(TransformPosition transform) → Position: Returns a position with all points transformed using transform.

Operators

operator ==(Object other) → bool: The equality operator.
inherited
operator [](int index) → num: A coordinate value by the coordinate axis index.

Static Methods

buildPosition<R extends Position>(Iterable<num> coords, {required CreatePosition<R> to, int offset = 0, Coords? type}) → R: Builds a position of R from coords starting from offset.
createFromObject<R extends Position>(Object position, {required CreatePosition<R> to, Coords? type}) → R: Creates a position of R from position (of R or Iterable<num>).
getDoubleList(Position position) → List<double>: Coordinate values of position as a double list of 2, 3 or 4 items.
getValue(Position position, int index) → num: A coordinate value of position by the coordinate axis index.
getValues(Position position) → Iterable<num>: Coordinate values of position as an iterable of 2, 3 or 4 items.
hash(Position position) → int: The hash code for position.
override
parsePosition<R extends Position>(String text, {required CreatePosition<R> to, Pattern? delimiter = ',', Coords? type}) → R: Parses a position of R from text.
testEquals(Position p1, Position p2) → bool: True if positions p1 and p2 equals by testing all coordinate values.
testEquals2D(Position p1, Position p2, {num? toleranceHoriz}) → bool: True if positions p1 and p2 equals by testing 2D coordinates only.
testEquals3D(Position p1, Position p2, {num? toleranceHoriz, num? toleranceVert}) → bool: True if positions p1 and p2 equals by testing 3D coordinates only.