uk.ac.starlink.ttools.func

Class Coverage

java.lang.Object

uk.ac.starlink.ttools.func.Coverage

public class Coverage
extends Object

Functions related to coverage and footprints.

One coverage standard is Multi-Order Coverage maps, described at http://www.ivoa.net/Documents/MOC/. MOC positions are always defined in ICRS equatorial coordinates.

MOCs may be specified using a string argument of the functions in one of the following ways:

• The filename of a MOC FITS file
• The URL of a MOC FITS file
• The identifier of a VizieR table, for instance "V/139/sdss9" (SDSS DR9)
• An ASCII MOC string, for instance "1/1 2 4 2/12-14 21 23 25 8/"

A list of all the MOCs available from VizieR can currently be found at http://alasky.u-strasbg.fr/footprints/tables/vizier/. You can search for VizieR table identifiers from the VizieR web page (http://vizier.u-strasbg.fr/); note you must use the table identifier (like "V/139/sdss9") and not the catalogue identifier (like "V/139").

Since:

29 May 2012

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
static boolean	inMoc(String moc, double ra, double dec) Indicates whether a given sky position falls strictly within a given MOC (Multi-Order Coverage map).
static boolean	nearMoc(String moc, double ra, double dec, double distanceDeg) Indicates whether a given sky position either falls within, or is within a certain distance of the edge of, a given MOC (Multi-Order Coverage map).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

inMoc

public static boolean inMoc(String moc,
                            double ra,
                            double dec)

Indicates whether a given sky position falls strictly within a given MOC (Multi-Order Coverage map). If the given moc value does not represent a MOC (for instance no file exists or the file/string is not in MOC format) a warning will be issued the first time it's referenced, and the result will be false.

Parameters:

moc - a MOC identifier; a filename, a URL, a VizieR table name, or an ASCII MOC string

ra - ICRS right ascension in degrees

dec - ICRS declination in degrees

Returns:

true iff the given position falls within the given MOC

nearMoc

public static boolean nearMoc(String moc,
                              double ra,
                              double dec,
                              double distanceDeg)

Indicates whether a given sky position either falls within, or is within a certain distance of the edge of, a given MOC (Multi-Order Coverage map). If the given moc value does not represent a MOC (for instance no file exists or the file/string is not in MOC format) a warning will be issued the first time it's referenced, and the result will be false.

Parameters:

moc - a MOC identifier; a filename, a URL, a VizieR table name, or an ASCII MOC string

ra - ICRS right ascension in degrees

dec - ICRS declination in degrees

distanceDeg - permitted distance from MOC boundary in degrees

Returns:

true iff the given position is within distance degrees of the given MOC