fv FITS file viewer and editor release

[William Pence]

FV 2.4 Release Announcement
                         November 24, 1998

Version 2.4 of the fv software tool for viewing and editing any FITS
format image or table is now available.  Fv has a graphical user
interface written using Tcl/Tk.  The Fv software distribution ships with
everything you need to build (i.e. you do not need Tcl/Tk already 
installed on your machine).  Fv has the following features (items
marked with a * are new with this release):

  *- fv runs under Windows 95/98/NT.

  *- Files can be opened (read-only) across the internet (http and ftp
     protocols). FTP sites can be browsed from the "Open File" dialog
     box. This feature is currently only available on Unix platforms.

  *- Filename completion eases browsing large directories and typing
     long names... type the first few letters of a filename and then
     hit TAB.

  *- Basic fv functions -- open, display, and plot data -- can be
     accessed from simple TCL scripts. 

   - A summary window lists the contents and size of all the
     extensions in the FITS file.

   - Entire extensions can be copied, cut, and pasted to/from the
     clipboard which can be saved to a new FITS file. 

  *- New, empty FITS files can be created. Empty extensions of any of
     the 3 basic types -- image, ASCII table, and binary table -- can
     be appended to existing files.

   - FITS headers may be displayed in a scrolling text window.  
     Keywords may be edited, inserted, or deleted, and an ASCII
     text listing of the header may be generated.

  *- Checksum keywords can be created or updated when a file is
     modified.

   - Selected columns in a FITS table may be viewed in a scrolling spread
     sheet.  The values in the table may be edited, and rows and columns
     may be inserted or deleted in the table.  The contents of the table
     may be saved to an ASCII text file.

  *- Keyboard shortcuts (ctrl-c and ctrl-v) simplify the copying and
     pasting of data between cells.

   - Tables can be sorted using multiple keys.
     
   - When sorting, rows with identical keys may be optionally deleted.

   - Table rows can be selectively deleted using a boolean expression
     evaluated for each row.

   - A spreadsheet calculator function allows you to create new columns
     by performing arithmetic on existing columns.

   - Line plots of one or more columns in a table may be generated.  
     Plots are displayed using the POW widget.  The user may then zoom 
     in on any area of interest in the plot. The plots may be saved and
     printed in postscript format.

   - Individual columns or pairs of columns can be used to produce 1D or
     2D histograms, respectively, and plotted in POW.

   - FITS images may be displayed with the usual pan, zoom, and color
     table manipulation facilities.  Users may choose to use the SAOtng
     image display tool (available separately from SAO), or the
     internal image display widget called POW that is supplied with fv.

  *- Double clicking an image displayed by POW will bring up a fv
     table of the image data with the clicked pixel highlighted.

   - Selected rows or columns of an image can be averaged and their
     pixels plotted in a line graph.


Items specific to the POW display widget...

   - POW supports interactive manipulation of the image colortable (i.e.
     contrast and bias twiddling).  

   - POW supports TrueColor displays and has more "colormap friendly"
     support for PsuedoColor display.  See the documentation for
     the "-cmap" fv command line switch or the POW "Color" help menu
     item for details.

  *- POW interprets standard FITS World Coordinate System (WCS) keywords,
     and optionally displays grid lines. (Version 2.4 adds WCS support for
     curves.)

   - Once displayed in POW, the contents of graphs can be edited and
     multiple graphs can be merged into one. Coordinate information
     (labels, pixel sizes, WCS parameters, etc) can be modified as well. 

  *- Graphs (including those containing images) can be arbitrarily resized.
     Previous versions only supported integral zoom levels.

  *- Multiple images can be mosaiced within a single graph. The only
     restriction is that the images have identical rotations.

  *- Each curve plotted in a graph can be displayed in a number of
     line styles/widths, point shapes/sizes, and colors. A single
     dialog box controls both the graph-level features (labels,
     contents, etc) and the display styles of each of a graph's
     curves.

   - POW can create, read, write, and graphically manipulate regions
     (boxes, circles, ellipses, polygons, lines, and points). (Data
     analysis of regions will be added in a later version.) 

   - POW can "blink" a set of images or graphs in rapid sequence. A 3D
     image cube can be animated in this manner. 

  *- POW can create contour maps of images.


Fv currently runs on many Unix platforms, including SUN O/S, SUN
Solaris, Dec OSF, and Linux PCs. With this release binaries for
Windows PCs are also available.  We plan to port fv to run under Mac
OS in the coming year.

Fv may be obtained from the HEASARC (High Energy Astrophysics Science
Archive Research Center) FTOOLS Web site at:

         http://heasarc.gsfc.nasa.gov/ftools/fv.html

See the INSTALL file in the fv distribution for instructions on installing
and running fv. Any comments or suggestions about fv should be sent to
ftoolshelp at athena.gsfc.nasa.gov.

--------
The fv development team currently consists of:

    William Pence:  Project Scientist, author of CFITSIO
    Lawrence Brown: Tcl/Tk programmer, original author of POW
    Peter Wilson:   Tcl/Tk programmer, fv/POW programmer        

fv and fitsTcl were originally written by Jianjun Xu.