This IDL facility provides a means to turn a HEALPix map into a image that can be visualized with Google Earth or Google Sky.

Location in HEALPix directory tree: src/idl/visu/hpx2gs.pro

FORMAT

IDL> hpx2gs, File, [Select, ] [COLT=, ... ... TITLEPLOT= ]

QUALIFIERS

File Required
name of a FITS file containing the HEALPix map in an extension or in the image field,
or name of an online variable (either array or structure) containing the HEALPix map (See note below);
if Save is set : name of an IDL saveset file containing the HEALPix map stored under the variable data
(default : none)

Select Optional
column of the BIN FITS table to be plotted, can be either
- a name : value given in TTYPEi of the FITS file
NOT case sensitive and can be truncated,
(only letters, digits and underscore are valid)
- an integer : number i of the column containing the data, starting with 1 (also valid if File is an online array)
default:1 for full sky maps, 'SIGNAL' column for FITS files containing cut sky maps

KEYWORDS

COORD_IN =: 1-character scalar, describing the input data coordinate system:
either 'C' or 'Q' : Celestial2000 = eQuatorial,
'E' : Ecliptic,
'G' : Galactic.
If set, it will over-ride the coordinates read from the FITS file header (when applicable). In absence of information, the input coordinates is assumed to be celestial.
The data will be rotated so that the output coordinates are Celestial, as expected by Google Sky
/HELP: Prints out the documentation header
KML =: Name of the KML file to be created (if the .kml suffix is missing, it will be added automatically) default:'hpx2googlesky.kml'
PNG =: Name of the PNG overlay file to be created. Only to be used if you want the filename to be different from the default (default: same as KML file, with a .png suffix instead of .kml)
RESO_ARCMIN =: Pixel angular size in arcmin (at the equator) of the cartesian map generated default:30
SUBTITLE =: information on the data, will appear in KML file GroundOverlay description field
TITLEPLOT =: information on the data, will appear in KML file GroundOverlay name field
COLT=, FACTOR=, FLIP=, GLSIZE=, GRATICULE=, HBOUND=,
HIST_EQUAL=, IGLSIZE=, IGRATICULE=, LOG=, MAX=, MIN=, NESTED=,
NO_DIPOLE =, NO_MONOPLE=, OFFSET=
OUTLINE=, POLARIZATION=, PREVIEW=,
QUADCUBE=, SAVE=, SILENT=: those keywords have the same meaning as in cartview and mollview

DESCRIPTION

hpx2gs reads in a HEALPix sky map in FITS format or from a memory array and generates a cartesian projection of it in a PNG file, as well as a Google Sky compatible KML file. Missing or unobserved pixels in the input data will be totally 'transparent' in the output file.

RELATED ROUTINES

This section lists the routines related to hpx2gs

: see cartview

EXAMPLE:

map = findgen(48)

hpx2gs, map, kml='my_map.kml',title='my map in Google'

produces in my_map.kml and in my_map.png an image of the input map that can be seen with Google Sky. To do so, start GoogleEarth or GoogleSky and open my_map.kml.

Eric Hivon 2010-06-18

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