NRAO Home > CASA > CASA Cookbook and User Reference Manual

7.3.1 Loading Data

The load tab of the Data Manager Panel allows you to interactively choose images or Measurement Sets to load into the viewer. The load tab automatically shows you the available images, Measurement Sets, and Display Panel States in the current directory that can be opened by the viewer. When you highlight an image in this view, the tab shows a brief summary of the image: pixel shape, extent of the image on the sky and in frequency/velocity, and restoring beam (if available).

Selecting a file will bring up information about that file in the panel on the right of the Data Manager Panel provide options for how to display the data. Images can be displayed as:

  1. raster image
  2. contour map
  3. vector map
  4. marker map

These options area each discussed in 7.4.

LEL: Instead of only loading an image from disk, you may ask the viewer to evaluate a ’Lattice Expression Language’ (LEL) expression ( 6.1.3). This can be entered in the box provided after you click the ”LEL” box. The images used in the LEL expression should have the same coordinates and extents.

Measurement Sets: A Measurement Set can only be displayed as a raster. For measurement sets, the load tab offers options for data selection. This will reduce loading and processing times for visibility flagging.

Regridding Images on Load: Optionally, you may regrid the velocity axis of an image on load to match the current coordinates grid in the Display Panel. In this case, the viewer will interpolate (using the selected interpolation scheme) the cube on disk to share the same velocity gridding as the loaded coordinates. This can be used, e.g., to overlay contour maps of different spectral lines or to make synchronized movies of multiple cubes. Note that the regridding depends on the rest frequency in the image, which is used to calculate the velocities used in regridding.


More information about CASA may be found at the CASA web page

Copyright 2010 Associated Universities Inc., Washington, D.C.

This code is available under the terms of the GNU General Public Lincense


Home | Contact Us | Directories | Site Map | Help | Privacy Policy | Search