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All zeros in image and weight
11-20-2009, 06:14
Post: #1
All zeros in image and weight
Hi, still trying to make large IRAS mosaics, and I'm running into problems for galactic longitudes between 180 and 270. The weights and images are being set to zeros uniformly. What might cause this sort of error? My default.swarp file looks like:

IMAGEOUT_NAME coadd_EIGA.fits # Output filename
WEIGHTOUT_NAME coadd_EIGA.weight.fits # Output weight-map filename

HEADER_ONLY N # Only a header as an output file (Y/N)?
HEADER_SUFFIX .head # Filename extension for additional headers

#------------------------------- Input Weights --------------------------------

WEIGHT_TYPE BACKGROUND # BACKGROUND,MAP_RMS,MAP_VARIANCE
# or MAP_WEIGHT
WEIGHT_SUFFIX .weight.fits # Suffix to use for weight-maps
WEIGHT_IMAGE # Weightmap filename if suffix not used
# (all or for each weight-map)

#------------------------------- Co-addition ----------------------------------

COMBINE Y # Combine resampled images (Y/N)?
COMBINE_TYPE SUM # MEDIAN,AVERAGE,MIN,MAX,WEIGHTED,CHI2
# or SUM

#-------------------------------- Astrometry ----------------------------------

CELESTIAL_TYPE NATIVE # NATIVE, PIXEL, EQUATORIAL,
# GALACTIC,ECLIPTIC, or SUPERGALACTIC
PROJECTION_TYPE TAN # Any WCS projection code or NONE
PROJECTION_ERR 0.001 # Maximum projection error (in output
# pixels), or 0 for no approximation
CENTER_TYPE ALL # MANUAL, ALL or MOST
CENTER 00:00:00.0, +00:00:00.0 # Coordinates of the image center
PIXELSCALE_TYPE MEDIAN # MANUAL,FIT,MIN,MAX or MEDIAN
PIXEL_SCALE 0.0 # Pixel scale
IMAGE_SIZE 0 # Image size (0 = AUTOMATIC)

#-------------------------------- Resampling ----------------------------------

RESAMPLE Y # Resample input images (Y/N)?
RESAMPLE_DIR . # Directory path for resampled images
RESAMPLE_SUFFIX .resamp.fits # filename extension for resampled images

RESAMPLING_TYPE LANCZOS3 # NEAREST,BILINEAR,LANCZOS2,LANCZOS3
# or LANCZOS4 (1 per axis)
OVERSAMPLING 0 # Oversampling in each dimension
# (0 = automatic)
INTERPOLATE N # Interpolate bad input pixels (Y/N)?
# (all or for each image)

FSCALASTRO_TYPE FIXED # NONE,FIXED, or VARIABLE
FSCALE_KEYWORD FLXSCALE # FITS keyword for the multiplicative
# factor applied to each input image
FSCALE_DEFAULT 1.0 # Default FSCALE value if not in header

GAIN_KEYWORD GAIN # FITS keyword for effect. gain (e-/ADU)
GAIN_DEFAULT 1.0 # Default gain if no FITS keyword found

#--------------------------- Background subtraction ---------------------------

SUBTRACT_BACK N # Subtraction sky background (Y/N)?
# (all or for each image)

BACK_TYPE AUTO # AUTO or MANUAL
# (all or for each image)
BACK_DEFAULT 0.0 # Default background value in MANUAL
# (all or for each image)
BACK_SIZE 128 # Background mesh size (pixels)
# (all or for each image)
BACK_FILTERSIZE 3 # Background map filter range (meshes)
# (all or for each image)

#------------------------------ Memory management -----------------------------

VMEM_DIR . # Directory path for swap files
VMEM_MAX 24000 # Maximum amount of virtual memory (MB)
MEM_MAX 24000 # Maximum amount of usable RAM (MB)
COMBINE_BUFSIZE 2047 # RAM dedicated to co-addition(MB)

#------------------------------ Miscellaneous ---------------------------------

DELETE_TMPFILES Y # Delete temporary resampled FITS files
# (Y/N)?
COPY_KEYWORDS OBJECT # List of FITS keywords to propagate
# from the input to the output headers
WRITE_FILEINFO N # Write information about each input
# file in the output image header?
WRITE_XML Y # Write XML file (Y/N)?
XML_NAME swarp.xml # Filename for XML output
VERBOSE_TYPE NORMAL # QUIET,NORMAL or FULL

NTHREADS 0 # Number of simultaneous threads for
# the SMP version of SWarp
# 0 = automatic



And the header is:
SIMPLE = T
BITPIX = 32
NAXIS = 2
NAXIS1 = 21600 / Cross-scan grid dimension
NAXIS2 = 1920 / In-scan grid dimension
OBJECT = 'p1705 ' / Object imaged by YORIC
CTYPE1 = 'GLON-CAR' / Decreases in value as sample index
COMMENT increases (orthographic projection)
CRVAL1 = 225. / GLON at origin (deg)
CRPIX1 = 10800. / Z-axis origin (cell)
CDELT1 = 0.004166666884 / Pixel Z-width (deg)
CTYPE2 = 'GLAT-CAR' / Increases in value as line index
COMMENT increases (orthographic projection)
CRVAL2 = 0. / GLAT at origin (deg)
CRPIX2 = 960. / Y-axis origin (cell)
CDELT2 = 0.004166666884 / Pixel Y-width (deg)



Thanks,
Adam
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02-06-2010, 18:14
Post: #2
RE: All zeros in image and weight
Hi Adam,

sorry for taking so much time to answer (!). Please tell me, does the header you give below correspond to an input image or to the output frame?
- Emmanuel.
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