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Blink mode limitations (and ways around them)

If you used the sgrb2n images in the example above, you'll notice that both images remained on channel 61 during blink mode. To look at a different channel, you could move back to normal mode, select a different channel, and return to blink mode to view both images on the new channel. A shortcut command for this is:

an.gotoz(67);     # change to channel 67, while still in 'blink' mode.

There is no way for the animator to tell the various images to display different channels; it has only a single frame number setting, which is communicated to all the images. There are several ways around this limitation, however.

• If you have a spectral image and a continuum (single-channel) image with the same sky projection and extents, the continuum image can be blinked or displayed along with whichever channel you select for the spectral image. For now, you should register the spectral image first, but that requirement will be removed soon.

• If your images have both a Stokes (polarization) axis and a Frequency axis, you can move the Stokes axis onto the animator, which will put the Frequency axes under separate slider controls within the 'Adjust' panels of each DisplayData. To accomplish this, press the 'Adjust' button on the DisplayPanel. Then, on both 'Adjust' panels that appear, open the 'Display' axes rollup, select 'Stokes' for the 'Z-axis', and press 'Apply' on both. The channel for each image can then be selected independently, from the 'Hidden axes' rollup of the corresponding Adjust panel.

  If your images don't have a Stokes axis, it's easy to give them one.

  include 'image.g'                     # (probably already included by now).
  im := image('nostokes.im');           # use the file name of your image here.
  imst := im.adddegaxes(stokes='I');    # add Stokes axis temporarily.
  ddst := dv.loaddata(imst, 'raster');  # load the new image tool
  mdp.register(ddst);                   # and register it on the displaypanel.
  

  You can save that stokes axis permanently if you wish, by adding an outfile parameter in the adddegaxes command above:

  imst := im.adddegaxes(stokes='I', outfile='hasstokes.im');
  

If your images cover a similar portion of the sky but have different projections or extents on it, you can view them both by regridding one to the projection and shape of the other, as follows:

im1 := image('first.im');       # use the file names of your
im2 := image('second.im');      # images here.
cs1 := im1.coordsys();          # coordinate system of the first image.
im2r:= im2.regrid(outfile='second-regrid.im', csys=cs1, shape=im1.shape());

im2r contains the second image regridded to the projection and shape of the first image. You can omit the outfile parameter if you don't need to save the regridded image permanently. You can now display and blink between the images im1 and im2r.

dd1 := dv.loaddata(im1,  'raster');  mdp.register(dd1);
dd2 := dv.loaddata(im2r, 'raster');  mdp.register(dd2);

Different images can always be displayed 'side-by-side' in completely separate DisplayPanel windows as well. In that case the the images need have nothing in common at all. There is no zoom synchronization or other 'linkage' between different DisplayDatas in the different panels, however.

The first item under the 'File' menu in one panel will bring up a new panel; registration of DisplayDatas, zooming, and animation can be controlled separately in each panel.