# Edit Objects

The Edit Objects dialog box has much the same layout as the Edit Graphs dialog box. It is divided into 3 regions...

At the top of the dialog box are two list boxes. The box on the left lists all known display objects (curves and images). The box on the right lists all known data objects. The number following the data objects' names indicates the number of values contained within each object. (The NULL data object is used to specify no data for certain elements of Curve objects.) The name of the display object being editted is indicated by the entry box below the left box. New objects are editted by simply entering a unique name. (Note that curves and images are treated separately, so one can have both a curve and image with the same name.) The Edit Data button on the right currently does nothing. In a future release, one will be able to edit old and create new data objects.

The middle portion of the dialog box lists the parameters defining the selected object. Using the pair of radio buttons at the top of this region one can alternate (or convert) between editting the object as a Curve or Image...

- Curve:

  A POW Curve is formed by specifying up to 4 data objects: X, Y, X-error, and Y-error. To assign data to the curve, highlight one of the data objects in the top right box and then click on the appropriate button in the curve parameter list. Either X or Y must be specified, but the others are all optional. If an X or Y data object is given as "NULL", POW will generate a simple integer count instead.

  A curve can contain WCS information which allows it to be plotted in celestial coordinates instead of pixels. Enter (or edit) the values at the bottom of the parameter list and select the WCS Info check box.

- Image:

  A POW Image is created from a single data object; highlight the desired data object and click on the Data button. The NULL data object cannot be used for an image. The Units entry box lists the units of the array values (not the X/Y coordinates). A data object is one-dimensional, so the image needs to know how to convert the data into a 2-D array. This is done by entering the X and Y Dimensions of the image in the first pair of entry boxes. Below them are the 3 image scale parameters. Origin specifies the coordinates of the center of the bottom left pixel of the image. By convention, FITS images have an origin of (1,1) when specified in pixels. The Pixel Size specifies the linear scale of the pixels (in units/pixel) and Units specify the physical units used for the Orign and Pixel Size.

  An image can contain WCS information which allows it to be labeled in celestial coordinates instead of pixels. Enter (or edit) the values at the bottom of the parameter list and select the WCS Info check box. WCS information overrides the image scale parameters (origin, pixel size, and units).

At the bottom of the dialog box are 3 buttons. Create Object creates the indicated object. If the Object Name is unique, a new object will be created otherwise, it will replace the old version. (Note than a curve and image can have the same name and but will still be considered unique.) Creating/Editting an object does not immediately affect the graphs in which that object already exists, so it is necessary to update them manual from the Edit Graphs dialog box. Reload Info will reset the parameter list and update the object/data boxes with the current list of known objects. The Exit button closes the dialog box. Any changes will be lost if an object wasn't created before exitting.