Package ucar.nc2.dataset

Class CoordinateSystem

  • @Immutable
public class CoordinateSystem
extends Object
    Specifies the coordinates of a Variable's values, this is a legacy class, use GridCoordinateSystem for new code. 
     Mathematically it is a vector function F from index space to Sn:
  F(i,j,k,...) -> (S1, S2, ...Sn)
  where i,j,k are integers, and S is the set of reals (R) or Strings.
    The components of F are just its coordinate axes: 
      F = (A1, A2, ...An)
    A1(i,j,k,...) -> S1
    A2(i,j,k,...) -> S2
    An(i,j,k,...) -> Sn
    Concretely, a CoordinateSystem is a set of coordinate axes, and an optional set of coordinate transforms. The domain rank of F is the number of dimensions it is a function of. The range rank is the number of coordinate axes.

    An important class of CoordinateSystems are georeferencing Coordinate Systems, that locate a Variable's values in space and time. A CoordinateSystem that has a Lat and Lon axis, or a GeoX and GeoY axis and a Projection CoordinateTransform will have isGeoReferencing() true. A CoordinateSystem that has a Height, Pressure, or GeoZ axis will have hasVerticalAxis() true.

    • Method Detail

      • makeName

        public static String makeName​(List<CoordinateAxis> axes)
        Create standard name from list of axes. Sort the axes first
        Parameters:
        axes - list of CoordinateAxis
        Returns:
        CoordinateSystem name, created from axes names

      • getCoordinateAxes

        public List<CoordinateAxis> getCoordinateAxes()
        Get the List of CoordinateAxes

      • getName

        public String getName()
        Get the name of the Coordinate System

      • getDomain

        public Collection<Dimension> getDomain()
        Get the Collection of Dimensions used by any of the CoordinateAxes.

      • findAxis

        @Nullable
public CoordinateAxis findAxis​(AxisType type)
        Find the CoordinateAxis that has the given AxisType. If more than one, return the one with lesser rank.
        Parameters:
        type - look for this axisType
        Returns:
        CoordinateAxis of the given AxisType, else null.

      • findAxis

        @Nullable
public CoordinateAxis findAxis​(AxisType... axisType)
        Find CoordinateAxis of one of the given types, in the order given.

      • getProjection

        @Nullable
public Projection getProjection()
        Get the Projection for this coordinate system.

      • isGeoXY

        public boolean isGeoXY()
        True if it has X and Y CoordinateAxis, and a Projection

      • isLatLon

        public boolean isLatLon()
        True if it has Lat and Lon CoordinateAxis

      • isGeoReferencing

        public boolean isGeoReferencing()
        True if isGeoXY or isLatLon

      • isComplete

        public boolean isComplete​(Variable v)
        Check if this Coordinate System is complete for v, ie if all v's dimensions are used by the Coordinate System. Exclude dimensions with length < 2.

      • isComplete

        public static boolean isComplete​(Collection<Dimension> variableDomain,
                                 Collection<Dimension> csysDomain)
        True if all variableDomain dimensions are contained in csysDomain, or have length < 2.

      • isCoordinateSystemFor

        public boolean isCoordinateSystemFor​(Variable v)
        Check if this Coordinate System can be used for the given variable, by checking if each CoordinateAxis can be used for the Variable. A CoordinateAxis can only be used if the CoordinateAxis' set of Dimensions is a subset of the Variable's set of Dimensions.

      • isImplicit

        public boolean isImplicit()
        Implicit Coordinate System are constructed based on which Coordinate Variables exist for the Dimensions of the Variable. This is in contrast to a Coordinate System that is explicitly specified in the file.

      • containsAxis

        public boolean containsAxis​(String axisFullName)
        Do we have the named axis?
        Parameters:
        axisFullName - (full unescaped) name of axis
        Returns:
        true if we have an axis of that name

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object