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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.64 imview
Requires:
Synopsis
View an image
Description
The imview task will display images in raster, contour, vector or marker form.
Images can be blinked, and movies are available for spectral-line image cubes.
Executing the imview task will bring up a display panel window, which can be resized. If no data file was specified, a Load Data window will also appear. Click on the desired data file and choose the display type; the rendered data should appear on the display panel.
A Data Display Options window will also appear. It has drop-down subsections for related options, most of which are self-explanatory.
The state of the imview task – loaded data and related display options – can be saved in a ’restore’ file for later use. You can provide the restore filename on the command line or select it from the Load Data window.
It is possible to use the viewer GUI tool to perform image manipulation and
analysis tasks that are not available from the command-line start.
Arguments
Inputs |
| ||
raster |
| (Optional) Raster filename (string) or complete raster
config dictionary. The allowed dictionary keys are file
(string), scaling (numeric), range (2 element numeric
vector), colormap (string), and colorwedge (bool).
| |
| allowed: | any |
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| Default: | variant
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contour |
| (Optional) Contour filename (string) or complete
contour config dictionary. The allowed dictionary keys
are file (string), levels (numeric vector), unit (float), and
base (float).
| |
| allowed: | any |
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| Default: | variant
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zoom |
| (Optional) zoom can specify intermental zoom (integer),
zoom region read from a file (string) or dictionary
specifying the zoom region. The dictionary can have two
forms. It can be either a simple region specified with blc
(2 element vector) and trc (2 element vector) [along with
an optional coord key (”pixel” or ”world”; pixel is the
default) or a complete region rectangle e.g. loaded with
”rg.fromfiletorecord( )”. The dictionary can also contain
a channel (integer) field which indicates which channel
should be displayed.
| |
| allowed: | any |
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| Default: | variant 1 |
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axes |
| (Optional) this can either be a three element vector
(string) where each element describes what should be
found on each of the x, y, and z axes or a dictionary
containing fields ”x”, ”y” and ”z” (string).
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| allowed: | any |
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| Default: | variant
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out |
| (Optional) Output filename or complete output config
dictionary. If a string is passed, the file extension is used
to determine the output type (jpg, pdf, eps, ps, png,
xbm, xpm, or ppm). If a dictionary is passed, it can
contain the fields, file (string), scale (float), dpi (int),
or orient (landscape or portrait). The scale field is used
for the bitmap formats (i.e. not ps or pdf) and the dpi
parameter is used for scalable formats (pdf or ps).
| |
| allowed: | any |
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| Default: | variant
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void
Example
The imview task provides access to a subset of all of the configuration
options for loading and configuring the display of images in the casaviewer.
This interface will evolve and eventually provide access to nearly all of
the image options available in the casaviewer.
To simply create a casaviewer to set up interactively, you can use:
imview
To open a particular image:
imview "ngc5921.clean.image"
to open an image and overlay a contour:
imview "ngc5921.clean.image", "ngc5921.clean.image"
or equivalently:
imview( raster="ngc5921.clean.image", contour="ngc5921.clean.image" )
to output an image:
imview( raster="ngc5921.clean.image", out="ngc5921-01.png" )
There are five optional parameters for imview -- raster, contour, zoom,
axes, and out. Each of these parameters can take a few different forms and
are treated as python dictionaries:
raster -- (string) image file to open
(dict) file (string) => image file to open
scaling (float) => scaling power cycles
range (float*2) => data range
colormap (string) => name of colormap
colorwedge (bool) => show color wedge?
contour -- (string) file to load as a contour
(dict) file (string) => file to load
levels (float*N) => relative levels
base (numeric) => zero in relative levels
unit (numeric) => one in the relative levels
zoom -- (int) integral zoom level
(string) region file to load as the zoom region
(dict) blc (numeric*2) => bottom left corner
trc (numeric*2) => top right corner
coord (string) => pixel or world
channel (int) => chanel to display
(dict) <region record> => record loaded
e.g. rg.fromfiletorecord( )
axes -- (string*3) demension to display on the x, y, and z axes
(dict) x => dimension for x-axes
y => dimension for y-axes
z => dimension for z-axes
out -- (string) file with a supported extension
[jpg, pdf, eps, ps, png, xbm, xpm, ppm]
(dict) file (string) => filename
format (string) => valid ext (filename ext overrides)
scale (numeric) => scale for non-eps, non-ps output
dpi (numeric) => dpi for eps or ps output
orient (string) => portrait or landscape
Examples:
1) A subset (zoom) of a raster image. Note the notation of curly brackets:
imview(raster="ngc5921.clean.image", out="ngc5921-02.png",
zoom={’channel’: 10, ’blc’: [113,109], ’trc’: [141,136]} )
2) An overlay of a raster image, ngc5921.clean.image, with a
contour map of the same image ngc5921.clean.image. Data ranges
are selected, as well as the colormap and the scaling cycles
of the raster image. Contours are autogenerated and The x-axis
will be Declination. The image is written out to a file named
myout.png in the png format.
imview(raster={’file’: ’ngc5921.clean.image’,
’range’: [-0.01,0.03],
’colormap’: ’Hot Metal 2’,
’scaling’: -1},
contour={’file’: ’ngc5921.clean.image’},
axes={’x’:’Declination’} ,
zoom={’channel’: 7, ’blc’: [75,75], ’trc’: [175,175],
’coord’: ’pixel’},
out=’myout.png’)
3) As example (2) but with an integral zoom level and no output to a file
imview(raster={’file’: ’ngc5921.clean.image’,
’range’: [-0.01,0.03],
’colormap’: ’Hot Metal 2’},
contour={’file’: ’ngc5921.clean.image’},
axes={’x’:’Declination’} ,
zoom=2)
4) Now, the contour levels are explicitely given, a region file is used
to define the zoom area
imview(raster={’file’: ’ngc5921.clean.image’,
’range’: [-0.01,0.03],
’colormap’: ’Hot Metal 2’},
contour={’file’: ’ngc5921.clean.image’,
’levels’: [-0.2, 0.2, 0.25, 0.3, 0.35, 0.4, 0.6, 0.8] },
zoom=’myregion.rgn’)
specifying "zoom={’file’: ’myregion.rgn’, ’channel’: 10}" would result
in the same level of zoom and would display channel number 10 from
the cube.
More information about CASA may be found at the
CASA web page
Copyright © 2016 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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