README
------
Authors: Pierre Fernique [Centre de Donnees astronomiques de Strasbourg]
Licence: GPL3

1) What is a MOC => http://ivoa.net/documents/MOC/
2) Where is the "main" class of this lib => cds.moc.HealpixMoc
3) How to use MOC => cds.moc.MocExample.java
4) How to check that my MOC is valid: http://alasky.u-strasbg.fr/MocServer/lint
5) Examples: 

a) Create and save a MOC:

   // Assuming that you have a Collection/array of longs
   // which represent the Healpix (NESTED) cell numbers of your spatial region
   // at a dedicated "order" (note: order = HealpixMoc.log2(nside) ).
   // You want to create the MOC a save it in a file.
   HealpixMoc moc = new HealpixMoc();
   moc.add( order, array );
   moc.write( filename );

b) Load and compare MOCs:

   // You want to load a MOC from a file and compute the intersection with
   // a spatial region that you provide as a MOC (written in ASCII format)
   HealpixMoc moc, myMoc, interMoc;
   moc = new HealpixMoc();
   mod.read( filename );
   myMoc = new HealpixMoc("3/1,2,3 4/17-19");
   interMoc = moc.intersection( myMoc );
   
c) Generate a MOC from a Collection of sky coordinates

   // You want to generate the MOC covering a set of sky positions.
   // The MOC is generated at a dedicated resolution "mocOrder=13"
   // Note: angRes = Math.sqrt( 4*Math.PI/(12*HealpixMoc.pow2(order) * 
   //                                         HealpixMoc.pow2(order) ) )

   HealpixMoc moc = new HealpixMoc(13);
   Healpix hpx = new Healpix();
   for( int i=0; i<100000; i++ ) {
      double lon = Math.random()*360;
      double lat = Math.random()*180 -90;
      moc.add( hpx, lon, lat);
   }