CoordinateSystem
Description
- Derived from
-
GeoObject abstract
Describes a coordinate system for geo-referencing.
A geographic coordinate system (IsGeographic is true
) has the following X
and Y
axes:
-
X
: Geodetic latitude
Angle from the equatorial plane to the perpendicular to the ellipsoid through a given point, northwards treated as positive. -
Y
: Geodetic longitude
Angle from the prime meridian plane to the meridian plane passing through the given point, eastwards treated as positive.
A projected coordinate system (IsProjection is true
) has the following X
and Y
axes:
-
X
: Easting
East pointing axis used in 2D projected coordinate systems. -
Y
: Northing
North pointing axis used in 2D projected coordinate systems.
A local coordinate system (IsLocal is true
) has the following axes:
-
X
:
Horizontal coordinate without additional semantic. -
Y
:
Vertical coordinate without additional semantic.
The standard Z
axis for a coordinate system is (Vertical is null
):
-
Z
: Ellipsoidal height
Distance of a point from the ellipsoid measured along the perpendicular from the ellipsoid to this point. Positive if upwards or outside of the ellipsoid.
Vertical coordinate systems (Vertical is not null
) have a different Z
axis, usually gravity-related height or depth.
Public / Constants
PopularMercator
WGS 84 / Pseudo-Mercator
This coordinate system is used by popular web mapping applications.
PopularMercatorCoordinate
The maximum absolute map coordinate value of PopularMercator.
These are the bounds of a square PopularMercator map:
180°W => -X 180°E => +X Y°S => -Y Y°N => +Y
where X
is PopularMercatorCoordinate and Y
is PopularMercatorLatitudeDeg
PopularMercatorLatitudeDeg
The absolute latitude (in degrees) that results in a map coordinate that is equal to PopularMercatorCoordinate.
PopularMercatorLatitudeRad
The absolute latitude (in radians that results in a map coordinate that is equal to PopularMercatorCoordinate.
WGS84
World Geodetic System 1984 (2D)
This coordinate system is supposed to be used when the Z-axis (height) is irrelevant.
WGS84_3D
World Geodetic System 1984 (3D)
This is the same as WGS84, except that this coordinate system explicitly uses ellipsoid height as the Z-axis.
Public / Constructors
FromWkt
Creates a new instance of CoordinateSystem based on the given well-known text representation (WKT) of a coordinate reference system.
The given string must match the following Grammar:
wkt := value ; obj := id !> open null* values close ; !value := obj | str | num ; values := value (',' null* value)* null* ; num := float ; !id := letter (letter | digit)* ; !close := ']' | ')' ; letter := 'a'..'z' | 'A'..'Z' | '_' ; null := ',' ; !open := '[' | '(' ; str := '"' (]"[ | '""')* '"' ;
- ValidatingException
-
If the given wkt in source code is malformed or invalid.
Topocentric
Creates a topocentric coordinate system.
This method delegates to CoordinateOperationMethod.Topocentric using the CoordinateOperationMethod depicted by method opt.
Public / Methods
CreateCoordinateTransform
Creates a ICoordinateTransform for this projected or geographic coordinate system.
- GeorefException
-
If the geo-reference parameters are incomplete or invalid.
CreateCoordinateTransformNull
Creates a ICoordinateTransform for this projected or geographic coordinate system.
ToCubemapFace
Creates a cubemap face geographic coordinate system based on this coordinate system.
First, the projection is removed (if present). Then, a cubemap face projection (see CoordinateOperationMethod.Face) is constructed based on the ellipsoid.
ToGeographic
Returns the base geographic coordinate system by removing the projection.
If this coordinate system if already geographic (see IsGeographic) or local (see IsLocal), this method returns this
.
ToLocalSpace
Computes a combined rotation/scaling matrix that transforms from this projected 3D coordinate system to terrain local-space, as defined by IGeometry.ComputeLocal1.
For computing the transformation matrix, this method takes the Flags and ProjectionUnit properties into account.
Public / Attributes
GeographicScale
Returns the approximate scale factor from the geographic unit to the horizontal unit.
The returned scale factor has the highest precision at the equator.
HorizontalUnit
Returns the horizontal unit of measure.
Depending on the coordinate system type, the horizontal unit of measure is either the local unit, projected unit or the unit of the ellipsoid of the geodetic datum.
IsGeographic
Is this a geographic coordinate system?
Geographic coordinate system use geographic coordinates (latitude, longitude), which are specified in angular units. A coordinate system can either be geographic, projected or local.
IsLocal
Is this a local coordinate system?
Local coordinate systems use custom map coordinates, which are specified in length units. A coordinate system can either be geographic, projected or local.
IsProjection
Is this a projected coordinate system?
Projected coordinate systems use map coordinates (easting, northing), which are specified in length units. A coordinate system can either be geographic, projected or local.
IsVertical
Does this coordinate system include vertical coordinates that are different from ellipsoid height?