Class HealpixTableInfo

java.lang.Object
uk.ac.starlink.table.HealpixTableInfo

public class HealpixTableInfo extends Object
Defines how to store metadata in a table so that STIL knows it contains a HEALPix map.
Author:
Mark Taylor
  • Field Details

    • HPX_LEVEL_INFO

      public static final ValueInfo HPX_LEVEL_INFO
      Metadata element for HEALPix level (=log2(nside)). Name "STIL_HPX_LEVEL", class Integer.
    • HPX_ISNEST_INFO

      public static final ValueInfo HPX_ISNEST_INFO
      Metadata element * for HEALPix ordering (true=NESTED, false=RING). Name "STIL_HPX_ISNEST", class Boolean.
    • HPX_COLNAME_INFO

      public static final ValueInfo HPX_COLNAME_INFO
      Metadata element for name of column storing pixel index. If blank, indexing is implicit (determined by row index). Name "STIL_HPX_COLNAME", class String.
    • HPX_CSYS_INFO

      public static final ValueInfo HPX_CSYS_INFO
      Metadata element for character indicating sky system: C, G or E. Name "STIL_HPX_CSYS", class String.
  • Constructor Details

    • HealpixTableInfo

      public HealpixTableInfo(int level, boolean isNest, String ipixColName, HealpixTableInfo.HpxCoordSys csys)
      Constructor.
      Parameters:
      level - healpix level; negative means not defined
      isNest - true for nested, false for ring
      ipixColName - name of column containing pixel index, or null for implicit pixel indices
      csys - healpix coordinate system variant
  • Method Details

    • getLevel

      public int getLevel()
      Returns the HEALPix level.
      Returns:
      log2(nside), or negative value if not defined
    • isNest

      public boolean isNest()
      Indicates pixel ordering scheme.
      Returns:
      true for NESTED, false for RING
    • getPixelColumnName

      public String getPixelColumnName()
      Returns the name of the table column containing the HEALPix pixel index. If blank, pixel index is assumed equal to row index.
      Returns:
      pixel column name, or null
    • getCoordSys

      public HealpixTableInfo.HpxCoordSys getCoordSys()
      Returns the HEALPix coordinate system variant used by this table. May be null if none specified.
      Returns:
      coordinate system object, or null
    • toParams

      public DescribedValue[] toParams()
      Exports the contents of this object to a list of DescribedValue objects that can be attached to a table's parameter list, to declare the organisation of HEALPix information in that table.
      Returns:
      list of table parameters
    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object
    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object
    • toString

      public String toString()
      Overrides:
      toString in class Object
    • isHealpix

      public static boolean isHealpix(List<DescribedValue> params)
      Indicates whether a list of table parameters appears to be from a table with HEALPix annotations as expected by this class. This method currently just looks to see whether any of the HPX_* ValueInfos appears in the list, and returns true if so.

      This method may be useful to determine whether it's worth while to call fromParams(java.util.List<uk.ac.starlink.table.DescribedValue>).

      Parameters:
      params - list of DescribedValue objects, as obtained from Table.getParameters
      Returns:
      true if the table appears to be a healpix table
    • fromParams

      public static HealpixTableInfo fromParams(List<DescribedValue> params)
      Imports HEALPix information from a list of table parameters, and turns it into an instance of this class. This should always succeed, but the returned instance is not guaranteed to have very complete information. If parameters that this class knows about seem to have wrong or surprising values, messages may be reported through the logging system.
      Parameters:
      params - list of DescribedValue objects, as obtained from Table.getParameters
      Returns:
      an instance of this class