Package hec.map.crs

Interface CoordinateReferenceSystem


public interface CoordinateReferenceSystem
Abstract coordinate reference system, usually defined by a coordinate system and a datum. The concept of a coordinate reference system (CRS) captures the choice of values for the parameters that constitute the degrees of freedom of the coordinate space. The fact that such a choice has to be made, either arbitrarily or by adopting values from survey measurements, leads to the large number of coordinate reference systems in use around the world. It is also the cause of the little understood fact that the latitude and longitude of a point are not unique. Without the full specification of the coordinate reference system, coordinates are ambiguous at best and meaningless at worst. However for some interchange purposes it is sufficient to confirm the identity of the system without necessarily having the full system definition.

The concept of coordinates may be expanded from a strictly spatial context to include time. Time is then added as another coordinate to the coordinate tuple. It is even possible to add two time-coordinates, provided the two coordinates describe different independent quantities. An example of the latter is the time/space position of a subsurface point of which the vertical coordinate is expressed as the two-way travel time of a sound signal in milliseconds, as is common in seismic imaging. A second time-coordinate indicates the time of observation, usually expressed in whole years.

  • Method Summary

    Modifier and Type
    Method
    Description
    The primary name by which this object is identified.
    Returns the unit system used by this coordinate reference system.
    Returns a Well Known Text (WKT) for this object.
  • Method Details

    • toWKT

      String toWKT()
      Returns a Well Known Text (WKT) for this object.
      Returns:
      The Well Know Text for this object.
    • getName

      String getName()
      The primary name by which this object is identified.
      Returns:
    • getUnit

      String getUnit()
      Returns the unit system used by this coordinate reference system.
      Returns: