fv Help: starting FV

### Starting FV

To start up fv on Unix workstations, enter 'fv' in a command window. You may optionally append the name of a FITS file, or multiple files, to be opened. For example, 'fv ngc1316o.fit' opens a single file, and 'fv ngc*' opens all the FITS files in the current directory whose names match the string. On PCs running MS Windows you may start fv either by double clicking on the fv desktop icon, or by dragging a FITS file from e.g. Windows Explorer onto the fv icon. It is also possible to set up your Windows or Unix environment so that you can just double click (in the File Manager or on an e-mail attachment) on a FITS file that has a standard extension like '.fit' or '.fits' and then have fv automatically start up and open that file.

### Environment Variable FVTMP

The environment variable FVTMP defines the directory that fv will use to create temporary files. On Unix machines, you may set this variable in your .login file, or in a .[t]cshrc file as

setenv FVTMP /temporary/directory/path

or in a .bashrc as

export FVTMP=/temporary/directory/path

Under MS Windows, open the Control Panel and click on System and Environment tabs, and type "FVTMP" in Variable entry box and disk:\temporary\directory\path in the Value entry box.

### cmap Option

Fv usually chooses an appropriate color map value by default, but it sometimes fails to recognize architectures supporting TrueColor mode and fails with a "X Error: BadMatch" message. The solution to this is to restart fv with the -cmap 2 option.

Here is a list of available cmap options when starting fv (e.g., 'fv -cmap 2':

     cmap 0 - Default behavior.  I.e. choose the "best" colormap.
     cmap 1 - Force POW to setup a new private pseudocolor colormap (very safe)
     cmap 2 - Force POW to use truecolor mode (very safe, but looks bad on low
              color displays and runs slower than pseudocolor).  Note: this will
              cause powSetupColormap to look for a truecolor visual; if it can't
              find one, it will allow the main Tk code to pick a visual, but POW
              will still use "truecolor mode" (i.e. the Tk photo widget) to
              display images.
     cmap 3 - Force use of the screen default colormap. This should be
              reasonably safe now, but often won't be what you want.

Go to About fv.