This IDL facility provides a means to visualise a Gnomonic projection (radial projection onto a tangent plane) of HEALPix and COBE Quad-Cube maps in an IDL environment. It also offers the possibility to generate GIF, PNG and Postscript color-coded images of the projected map. The projected (but not color-coded) data can also be output in FITS files and IDL arrays.

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

FORMAT

IDL> GNOMVIEW, File, [ Select, ] [ /ASINH, CHARSIZE=, CHARTHICK=, COLT=, COORD=, /CROP, EXECUTE=, FACTOR=, FITS=, /FLIP, GAL_CUT=, GIF=, GLSIZE=, GRATICULE=, /HALF_SKY, HBOUND=, /HELP, /HIST_EQUAL, HXSIZE=, IGLSIZE=, IGRATICULE=, /LOG, MAP_OUT=, MAX=, MIN=, /NESTED, /NO_DIPOLE, /NO_MONOPOLE, /NOBAR, /NOLABELS, /NOPOSITION, OFFSET=, OUTLINE=, PNG=, POLARIZATION=, /PREVIEW, PS=, PXSIZE=, PYSIZE=, RESO_ARCMIN=, RETAIN=, ROT=, /SAVE, /SHADED, /SILENT, SUBTITLE=, TITLEPLOT=, TRANSPARENT=, TRUECOLORS=, UNITS=, WINDOW=, XPOS=, YPOS=]

QUALIFIERS

: For a full list of qualifiers see mollview

KEYWORDS

: For a full list of keywords see mollview

DESCRIPTION

gnomview reads in a HEALPix sky map in FITS format and generates a Gnomonic projection of it, that can be visualized on the screen or exported in a GIF, PNG, Postscript or FITS file. gnomview allows the selection of the coordinate system, point of projection, map size, color table, color bar inclusion, linear or log scaling, histogram equalised color scaling, maximum and minimum range for the plot, plot-title etc. It also allows the representation of the polarization field.

RELATED ROUTINES

This section lists the routines related to gnomview

: see mollview

EXAMPLE # 1:

gnomview, 'planck100GHZ-LFI.fits', rot=[160,-30], reso_arcmin=2., $

$\quad$ pxsize = 500., $

$\quad$ title='Simulated Planck LFI Sky Map at 100GHz', $

$\quad$ min=-100,max=100

gnomview reads in the map 'planck100GHZ-LFI.fits' and generates an output image of the size of 500 x 500 screen pixels, with a resolution of 2 arcmin/screen pixel at the center. The temperature scale has been set to lie between $\pm$ 100, and the units will show as $\mu$ K. The title 'Simulated Planck LFI Sky Map at 100GHz' has been appended to the image. The map is centered at (l=160, b=-30)

EXAMPLE # 2:

map = findgen(48)

triangle= create_struct('coord','G','ra',[0,80,0],'dec',[40,45,65])

gnomview,map,/online,res=25,graticule=[45,30],rot=[10,20,30],$

$\quad$ title='Gnomic projection',subtitle='gnomview', $

$\quad$ outline=triangle

makes a gnomic projection of map (see Figure 1b on page ) after an arbitrary rotation, with a graticule grid (with a 45^o step in longitude and 30^o in latitude) and an arbitrary triangular outline

Eric Hivon 2010-06-18

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