Causes the specified 2-D data to be displayed, via ds9.
sherpa> IMAGE <arg> [# [ID]]
# specifies the number of the dataset (default dataset number is 1).
The ID modifier is used for displaying background datasets, and then if
and only if the Sherpa state object variable multiback is set to 1,
i.e., if more than one background dataset is to be associated with a
single source dataset. The ID modifier may be any unreserved string
(e.g., A, foo, etc.), i.e., a string that is not a parsable command.
The argument <arg> may be any of the following:
IMAGE Command Arguments
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{{DATA | DCOUNTS} |
{BACK | BDCOUNTS}}
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The source|background data values
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{ERRORS |
BERRORS}
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The estimated total errors for the source|background data values
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{SYSERRORS |
BSYSERRORS}
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The assigned systematic errors for the source|background data values
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{STATERRORS |
BSTATERRORS}
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The estimated statistical errors for the source|background data values
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{{MODEL | MCOUNTS} |
{BMODEL | BMCOUNTS}}
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The (convolved) source|background model amplitudes
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{FIT |
BFIT}
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The data, model, and absolute residuals for source|background, displayed in
three frames
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{DELCHI |
BDELCHI}
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The sigma residuals of the source|background fit: (data - model)/error
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{RESIDUALS |
BRESIDUALS}
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The absolute residuals of the source|background fit: (data - model)
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{RATIO |
BRATIO}
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The ratio (data/model) for source|background
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{CHI SQU |
BCHISQU}
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The contributions to the chi-square statistic
from each source|background data point
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{STATISTIC |
BSTATISTIC}
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The contributions to the current statistic
from each source|background data point
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{WEIGHT |
BWEIGHT}
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The statistic weight value assigned to each source|background data point
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{FILTER |
BFILTER}
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The mask value (0|1) for each source|background data point
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<sherpa_model_stack>
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The (unconvolved) model amplitudes for the
specified model stack (SOURCE,
{BACKGROUND|BG}, or
[B]NOISE)
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<model_stack>
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The (unconvolved) model amplitudes for the
specified user-defined model stack
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<sherpa_modelname>
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The (unconvolved) amplitudes of the specified model component
(e.g., GAUSS2D)
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<modelname>
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The (unconvolved) amplitudes of the specified model component
(e.g., g)
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{EXPMAP |
BEXPMAP}
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The unfiltered source|background 2-D EXPMAP file contents
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{PSF |
BPSF}
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The unfiltered source|background 2-D PSF file contents
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If there is no open image window when an IMAGE command
is given, one will be created automatically.
In CIAO 3.0, if one displays an image after filtering, what is displayed is
the <data to image> * filter", shown over the range of
the unfiltered dataset. In a future version of Sherpa,
include/exclude regions may also be
superimposed upon the image.
Also note that in CIAO 3.0, images are automatically resized to fit
entirely within the image frame. The user may of course
subsequently zoom in and/or out.
Related commands include
IGNORE IMAGE and
NOTICE IMAGE, which are used to
interactively define filter regions from an image display.
The Display chapter of the Sherpa Manual has more
information regarding data display capabilities, including modifying
various image characteristics.
It IS NOT possible to pass a Data Model virtual file specification
to this command. While you can read in a large file with
sherpa> data "image.fits[opt mem=1000]"
the following DOES NOT work:
sherpa> image "model[opt mem=1000]"
This is because "model" is a token that the Sherpa parser
interprets, and it will treat the rest of the string ("[opt
mem=1000]") as an error. A workaround is to write out the file with
the "write" command:
sherpa> write model "out.fits[opt mem=1000]"
Then display out.fits in ds9.
Display 2-D data:
sherpa> DATA example_img.fits
sherpa> IMAGE DATA
The last command displays dataset number 1.
Dataset number 1 must be a 2-D dataset.
Exclude a 2-D region; display the filtered region:
sherpa> IGNORE FILTER "BOX(250,250,50,50)"
sherpa> IMAGE FILTER
The first command, IGNORE FILTER
"BOX(250,250,50,50)" defines a filter for dataset number 1.
The second command displays the defined filter region.
Display 2-D absolute residuals:
sherpa> PARAMPROMPT OFF
sherpa> SOURCE = GAUSS2D[g]
sherpa> FIT
sherpa> IMAGE RESIDUALS
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