DatumShiftDirection Enumeration
Specifies the forward direction of a DatumShift.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CECore assembly)
Syntax
public enum DatumShiftDirectionValues
| Value name | Value | Description |
|---|---|---|
| ToKnownDatum | 0 | The forward direction goes from the owner datum to the known datum. |
| FromKnownDatum | 1 | The forward direction goes to the owner datum from the known datum. |
Remarks
For a DatumShift to be useful, it must be able to transform coordinates in both directions. But there is usually one forward direction, which is easy to implement, and one backward direction, which is more cumbersome. The DatumShiftDirection values specifies which way the forward direction is.
For example, if a HelmertDatumShift has been constructed from an entry in the EPSG database, and has Wgs84 as its DatumShift.KnownDatum, then the HelmertDatumShift.Direction should be ToKnownDatum, since EPSG has normalized all datum shifts related to Wgs84 so that they go from a national datum to Wgs84.
On the other hand, national sources often express their datum shifts in the opposite direction.
Platforms
Windows, Linux, Android