fv: Features

fv is a general-purpose FITS file editor (formerly just a file viewer) able to manipulate virtually all aspects of a FITS file and perform basic data analysis of its contents.

(Highlighted items are new in version 5.5)

• Enhancement: Updated for compatibility with new Hera web server and HTTPS connections.
• Bug fixed: Various compatibility issues with iwidgets 4.1.0 and Tcl/Tk 8.6.x.
• Bug fixed: Issue with vector column plotting.
• Enhancement: Updated for compatibility with Tcl/Tk 8.6.x.
• Enhancement: Updated to handle HTTPS connections.
• Bug fixed: Displaying vector columns with ds9 generated a large temporary data file.
• Bug fixed: Error after exiting Hera.
• Bug fixed: Text dump of vector column was changing NULLs to non-zero values.
• Bug fixed: Retain fv graph preference size.
• Bug fixed: Adding arithmetic function in expression when plotting resulted in seg fault.
• Bug fixed: fv summary information of primary extension name changed after closing header view.
• Bug fixed: Print preview panel did not resize correctly.
• Bug fixed: HDU export from fv was not working.
• Bug fixed: Problems in graph options editing.
• Bug fixed: Error messages about "missing rootx and rooty" and regarding Editing Objects initialization.
• Bug fixed: WCS projection for vector image column.
• Bug fixed: Errors when displaying or exporting slices of a data cube.
• Bug fixed: For logical columns of a binary table, display 'U' (undefined) for illegal values (anything other than 'T', 'F', or 0) rather than interpreting the values as 'F'.
• Bug fixed: Memory faults when trying to open a FITS file that has a binary table with non-zero variable length array columns but has no rows.
• Bug fixed: Fix large FITS file crashing and displaying summary/header issue.
• Enhancement: Adding wcsfix routine to handle non-standard WCS keywords values in FITS header.
• Bug fixed: correct FITS Header string to WCSLib overflow 80 characters limit per card.
• Enhancement: denote -SIP projection to its counter-part (i.e. -TAN-SIP to -TAN projection.)
• Bug fixed: file selection panel not been displayed during exiting fv/pow application when the FITS file is modified during the session.
• Passing Fits Header string and cnt to client to display wcs info correctly for Hera and POWplot operation.
• Horizontal scrolling bug of 0 rows table.
• Add 2 new icons: Hera and Student Hera during installation for Microsoft Windows and Apple Mac OS X.
• Allow display of 64 bits integers in fv data table and in POW imagery.
• Fix saving 64 bits integer data to a text file bug.
• "Run Ftools..." option is no long available. Users are encouraged to use the new "fgui" task that is distributed with ftools.
• "Skyview..." catalog selection is now only available via "Catalog..." option.
• Adding capability to re-order the display of FITS columns.
• Expand capability to sorting/modification of FITS columns parameters.
• Tracking parent window view via vector columns in "Expand"ed view .
• Allow user to specify path for DS9 and XPA in Windows.
• Fix Windows platform of printing countor map on image problem.
• Modified how the rotation angle in region files is interpreted to be consistent with DS9 (angle is w.r.t. the North direction in the image).
• Add capability to handle more than 9 parameters.
• Add capability to invoke future HERA modules.
• Fix running FTOOLS tools not copying physical par file problem.
• Add capablity to display 4D table and image (movie).
• Update logic for display CAR projection.
• Change vizier/skyview/catalog file naming scheme.
• Rework background backup directory cleanup logics.
• fv runs under most major operating systems: Unix/Linux, Windows, and Mac OS.
• Basic fv functions -- open, display, plot data, sort, save, close -- can be accessed from simple TCL scripts. With the XPA package (available separately from SAO) for unix, fv can be controlled by other programs. On Mac OS, fv can be controlled with AppleScript. Sample programs written using XPA (C, Tcl, and Csh), Tcl, and AppleScript are included.
• Added more XPA scripting command for controlling fv from external processes, including create (create an image or table file or extension), export (export hdu to a Fits file or a text file), opentool (open skyview, catalog, vizier or ftools dialog panel) and preference (set up FV preferences). See Scripting for more information.
• Adding support for Cartesian projection.
• Adding record capability for profile of FITS image.
• Enhanced capabilities for printing and saving FITS image or plot, including the ability to preview the image before printing.
• A row selection function was added to fv. User can select/deselect row(s) by clicking on the row index in the table with the mouse's left button (or clicking left button then right button to select row range). Row(s) also can be selected using selection condition and expression.
• fv's plot, calculator, histogram and statistics tools now can perform on the selected rows.
• Export command can export the selected rows and columns from a table to fits file or text file.
• Delete command will now delete the selected rows and cols.



• Add short cut on the selection panel to allow users access fv preference quickly.
• Files can be opened (read-only) across the internet (http and ftp protocols). FTP sites can be browsed from the "Open File" dialog box.
• The SkyView online database can be searched for images of and object lists for a region of the sky. Results are downloaded in FITS format which then can be plotted.
• Filename completion eases browsing large directories and typing long names... type the first few letters of a filename and then hit TAB.



• 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.



• Enhanced support for ds9 image display. User can choose to display images or plots using either DS9 or POW as the primary display tool.
• Function buttons incorported to the File Summary window to provide short cuts to common operations: 'Hist' (displays a histogram image of 1 or 2 columns in a table), 'Plot' (plots table columns), 'Table All' and 'Table Select' (The first button displays all the columns in a table, whereas the second button allows the user to select which columns to display).
• When displaying Hierarchical grouping tables, a new 'OPEN' button is available at the beginning of each row which can be used to open the corresponding group member file.
• Can display and edit images that are compressed with the new FITS 'Tile Compression' algorithm.
• 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 spreadsheet. The values in the table may be edited, and rows and columns may be inserted or deleted in the table. Tables can be sorted using multiple keys and rows with identical keys optionally deleted. Table rows can be selectively deleted using a boolean expression evaluated for each row. The contents of a table may be saved to an ASCII text file.
• Line plots of one or more columns (or arithmetic expressions involving one or more columns) in a table may be generated and displayed in the POW widget. Data can be extracted from a subset of rows; each row of a vector column can be plotted as a separate curve. Individual columns or pairs of columns can be used to produce 1D or 2D histograms, respectively, and plotted in POW.
• A spreadsheet calculator function allows you to create new columns by performing arithmetic on existing columns.
• FITS images may be displayed with the usual pan, zoom, and color table manipulation facilities. Users may choose to use the SAOtng or DS9 image display tools (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.
• FITS image data also may be displayed as a table, allowing individual pixels to be edited. Selected rows or columns can be averaged and their pixels plotted in a line graph. Image data can be smoothed using a boxcar filter.
• On Unix machines with FTOOLS installed, one can select and execute an FTOOL from within fv.
• An optional "Desktop Manager" allows for management of the various fv windows.
• Update calculator, calculator expression help files.
• Add licence.
• Fix interface to VizieR.

POW is a general-purpose graphing widget which can display and manipulate line plots and images.

• Bug fixed: Fix opening FITS files in read-only mode issue.
• Bug fixed: Fix scale error on colorbar.
• Bug fixed: Fix axial label and scale issue for image constructed from image table cells.
• Bug fixed: Fix no plot in pow scope area when displaying/flipping contour map (on separate graph.)
• Bug fixed: Fix grid displaying issue when flipping a plot.
• Bug fixed: Fix crashing issue when Zoom and then Reset zoom of images constructed from an image table.
• Bug fixed: Fix information missing when displaying movie from a 3-D image table.
• Bug fixed: when editing plot/image information, new title string is not been updated in the graph bug.
• Bug fixed: zoom/unzoom of plot/image cause labels and units of the graph disappeared.
• Bug fixed: fv/pow crashes during rendering of graph/image if the FITS file consists of inconsistence coordinates or unsupported coordinates system.
• Bug fixed: un-necessary X and Y labels displayed in POW window (no image/plot created yet) when xspec is invoked.
• Enhancement: allow the selection of columns panel to remain visible during plotting.
• Enhancement: allow renaming capability of created region files when running special analysis tools in Hera.
• Fix zoom in and out bugs on POW image.
• Support displaying images that straddle the 24h = 00h boundary on the sky with WCSLIB.
• Release memory when deleting/closing an image in POW (on-going).
• Fix editing graph parameter values bug.
• Fix "Duplicate Graph" casuing seg-fault bug.
• Fix two identical file names from two directories overwrite each other in POW bug.
• Fix image flipping bug with FITS keyword CDn_n.
• Fix displaying linear WCS projection and coordinates image.
• Overhauling POW world coordination calculation logics. Now fV/POW use standard WCSLIB library to generate world coordinates/pixel positions.
• Allow generating of plots that retains its world coordinate projection information.
• Allow limited editing capability on the property of graph objects (projection, rotation, etc) of a graph/image on the fly.
• Allow switching between multiply world coordination system (i.e. WCSa, WCSx, etc.) on the fly.
• Allow the flipping of image/plot of direction on X or Y or Both axes.
• Fix white-wash grey-out POW imagery on Scientific Linux platform bug.
• Allow display of 64 bits integers in fv data table and in POW imagery.
• Modified how the rotation angle in region files is interpreted to be consistent with DS9 (angle is w.r.t. the North direction in the image).
• Add capablity to calculate Flux on region.



• Add capability to handle "Physical" attribute in region file.
• Add capability to center (and resize) of ROI (region of interest) when the image is zoomed.
• Add capability to allow parameters editor to stay until user decided to cancel.
• Fix sorting Fits table but displaying wrong slice image problem.
• Fix rotation of coordinates results in wrong region specification problem.
• Fix plotting of selected rows from FITS table problem.
• Fix ploygon region handle placement and dragging mechanisms problem.
• Add X axis range selection utility in POW.
• Add capablity to create/display region on image.
• Add XPA entry points for X axis range selection and region display.
• Fix ploygon creation problem, allow right mouse button to drag the existing vertex, left mouse button for creation and move the region.
• Add color changes capability in Edit Region Panel.
• Fix one dimension plot/image label problem.



• An image's colortable (i.e. contrast and bias) can be interactively manipulated. More than 20 different color schemes can be selected.
• Histogram Equalization colormap intelligently distributes the colormap according to the distribution of pixel intensities in an image.
• POW supports TrueColor displays and has more "X 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.
• Text labels can be placed on a graph at a position fixed either to the graph (eg, a legend) or to the graph's coordinate system (eg, an object label).
• Font, size, and style of labels can be independently controlled for graph titles, axis labels, tick labels, and each text label.
• 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.



• Add preview capability. In this panel, user can also rotate, zoom to preview image.
• Allow user to save the image in POW display to one of these formats: bmp, jpeg postscript (default), png, pnm or tiff.
• Add directory preview to allow user to save image to different location on local disk
• Multiple images can be mosaiced within a single graph. The only restriction is that the images have identical rotations. (Well-separated WCS images will not be projected exactly, though.)
• A single intuitive dialog box controls virtually all aspects of a graph, from its contents and labels, to the tick mark spacing, to the display options of its curves, to the colormaps of its images.
• Each curve plotted in a graph can be displayed in a number of line styles/widths, point shapes/sizes, and colors. The color of a curve's points and connecting lines can have different colors. Graphs containing multiple curves will have different colors assigned to each curve.
• Log and semi-log graphs can be created from either logarithmic or regular curve data.

  

• Allow user to reverse the functionality of the left and right mouse buttons within the POW display via pow's preferences settings (default: Left mouse button - control zoom, right mouse button - control brightness/contrast).
• POW can create, read, write, and graphically manipulate regions (boxes, circles, ellipses, polygons, lines, and points). Supports new DS9 region file format.
• 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.
• Measure the distance between two points on a graph using the Ruler tool.
• Flux and centroid values for a region of an image can be calculated with the Probe tool.
• Plot an image cross-section with the Profile tool.
• A standalone tool, POWplot, can be used to display a single image without going through fv.
• Add A4 paper size.
• Rework print interfac.
• Fix preview orientation.
• Fix preview page layout.
• Add XPA entry points to print/save image on POW.
• Update profile help files.
• Graphs can be repositioned and resized, and regions of interest can be zoomed in on. The cursor's position within a graph and, for images, the pixel's value located there are displayed in a continuously-updated readout.

See the release notes for details on the changes from the previous version.