Under Development

Several components in CARTA are not completely integrated into the main tool but are included in this preview release.  This section outlines their intended functionality and limitations.

Image Stacks

The image stack functionality is in place to view multiple images together.  Image Stack functionality is part of the Image View settings.  If multiple images are loaded into the same Image View, then the Stack functionality will become active. The tool allows for the order of images to be determined and their relative transparency.  The stack tool will also allow for creation of RGB images in the future.  By selecting Auto Select and using the Up and Down buttons the order can be established.  By changing the Transparency slider, the opacity of the upper images can be controlled.  The Name field also allows the images in the stack to be given custom names.  

Image Stack Tool

At present, there is no provision for images on different coordinate grids and future work will allow multiple images to be transformed onto each other.


The profile tool summarizes information about two dimensional images along a third dimension.  The Profile tool currently only appears if added by the user through Customization.  The usual application of this tool is for analyzing Spectral Line Data cubes.  The figure below shows an example of the Profile tool, which uses a similar tabbed view as the Image View for controling the visualization.  The missing functionality represents how to show profiles of image subsets including the position under the cursor.  

Spectral Profile Tool


Display -- This tab controls the axes shown in the display including support for changing units.  This also controls where the plot annotations are displayed.

Range -- This controls what section of the spectrum is shown.  The Full button returns to the full spectral range.  This is useful since dragging across the spectrum will zoom to the region highlighted.

Profiles -- This controls what spectra are actually shown.  In particular, for regions and entire images, the Profiles tab allows for generating different measurements (Statistics) from the data such as the mean (average brightness over the region), RMS, etc.  Region selection and changing rest frequencies are not fully implemented.

Fit -- This tab allows for multi-Gaussian fitting to be used in the profile tool.  It is not fully implemented at present.

Curves -- This tab controls the appearance of the different profiles, including draw style and color.


The region drawing functionality allows you to select sub-regions within an image.  Region drawing and selection is not fully implemented and suffers from poor performance.  Region selection is currently controlled by the Image view in the Quick bar.  Selecting a region shape and then click+dragging will draw the desired shape of region.  This region will then connect to the profile and statistics tool.  Simple shapes are drawn through a click+drag action.  The polygon is controlled by clicking on the vertices in order and double-clicking to end drawing.  The figure below shows a Polygon region and its rectangular bounding box.

Region Example



The statistics panel provides information about the image or regions of interest in the image. The Statistics tool currently only appears if added by the user through Customization. By opening a statistics panel, several different statistics about the image and regions are displayed.  The user can select which statistics are displayed through the Statistics View settings, which is accessed in the Menu Bar or in the context menu, brought up with a right click.

Statistics Preview