To plot an overlay map.


The files created by DB_OVER can be used to draw the overlay maps with this command. The files contain the coordinates of the sky center fields, the stars positions and the coordinates of the superimposed objects written in an ad hoc format. This command use these coordinates to make the overlay maps on a specific graphic device. The user can read the next chapter to have more information about the hard copy devices available in his DIRA implementation.

INPUT FIELDS of the command:

Input File:

The name of the file created from DB_OVER command that must be used to produce overlay.

Example : FOR012.DAT

Output graphic device:

The name of the output graphic device. The user can enter a ? to have a list of the device available in his installation. The names are assigned by the system manager at the moment of the installation of DIRA package and have a different syntax when the AGL or GKS graphic library is in use.

Example : HPLOT

Plot overlay: from N. to N.

The DB_OVER command can create the data for more overlay at a time. Then the user can decide to plot only a subset of these. Here the user must enter the number of the first and of the last overlay map that he needs to plot.

Example : 10 25

Stars magnitude limits

If in a sky region the stellar density is too high then the overlay map can result confused because filled with too many symbols. The user can select, to avoid that, to plot the stars that have a magnitude greater than this value.

Example : 7.5

Size in cm. of the overlays x

In this fields the user must define the X and Y size of the output map. The values that are entered here must agree with the values of the scale and of the half width defined in the DB_OVER command. The user must pay attention to change the default values to avoid conflicts with the data in the input file

Example : 10.8 10.8


The output of this task is graphic metafiles (xxxxx.PLT) where xxxxx is a mnemonic for the graphic device type. The user must send these files to the physical device with an appropriate system command.

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