The Application Server allows the transformation of spatial data. I.e. it can perform the calculations to express the location shape and orientation (LSO) of a real world object specified in a specific spatial system and a specific spatial reference system in another spatial system and spatial reference system.
Not all transformations are possible under all conditions, E.g. spatial data expressed in a Projected system can not necessarily be expressed in an Axis Reference system. See table 1 for details about constraints for transformations between different spatial systems.
Note that transformation from one system to another and also transformations between different reference systems (nearly) always introduce a small error resulting from rounding errors. Therefore transforming to another spatial reference system and then transforming back to the original system will not always result in the same spatial data.
From |
To |
Notes |
Geographic |
Geographic |
Transformation of data expressed in different geographic coordinate systems is always possible. |
Geographic |
Projected |
In most cases the transformation of a geographic coordinate system to a projected coordinate system is possible. However the general restrictions of map projections apply. E.g. North pole cannot be projected to some projected coordinate systems. |
Geographic |
Axis Reference |
Spatial data defined in a Geographic coordinate system can be expressed in an axis reference system if there is an orthogonal projection of the Geographic geometry to the axis. For this to be true the spatial data in the geographic coordinate system is first transformed to projected coordinate system on which the axis is defined. After that the a transformation from projected to axis is performed (see below). |
Projected |
Projected |
Transformations of data expressed in different projected coordinate systems is possible. However the general restrictions of map projections apply. |
Projected |
Geographic |
Transformations of data expressed in a projected coordinate system to a geographic coordinate system is possible. The data is first transformed to the horizontal geographic coordinate system on which the projected coordinate system is defined and then transformed to the specified geographic coordinate system. |
Projected |
Axis Reference |
Spatial data in a Projected system can be expressed in an axis system if there is an orthogonal projection of the Projected geometry to the axis. The data is first transformed to the projected coordinate system on which the axis is defined (see above) and then the orthogonal projection is done. |
Axis Reference |
Axis Reference |
Transformations of data expressed in different axis reference systems on the same axis are always possible. Transformations between reference systems belonging to different axes are possible if there is a orthogonal projection of the axis interval in the source axis reference system to the destination reference system. The data in the source reference system is first transformed to the underlying projected coordinate system after that it is transformed to the underlying projected coordinate system of the target axis and then the orthogonal projection is carried out. |
Axis Reference |
Geographic |
Spatial data in an axis system can always be expressed in any Geographic system. |
Axis Reference |
Projected |
Spatial data in an axis system can always be expressed in any Projected system defined upon a Geographic system. |
Table 1: Transformations between spatial systems and constraints for these transformations.
