gr47@sdcc12.ucsd.EDU (gr47) (11/07/87)
---------------------------------------------------------------- I have not been following this newsgroup so please bear with me... My research group has been using the National Center for Atmospheric Research (NCAR) graphics package for contouring, mapping and xy-plotting for several years now. NCAR recently started distribution of a new package that conforms to GKS level 0A standards. NCAR recommends buying a higher level GKS package to take care of the low-level graphics tasks. Where can I find out what the different levels of GKS correspond to in practical terms? I am particularly interested in a package written at U. Lowell, MA that conforms to level 2A. Can someone give me a quick rundown on 2A and/or some refs to GKS level descriptions? I have looked at 'Introduction to the Graphical Kernel System G.K.S' by Hopgood et al., 1983, but it doesn't say anything about the different levels -- does the 1986 ed.? What really got me going on this is a need for more interactive plotting in our group - to move an x-axis label in our present system takes modifs to a Fortran program, recompilation, re-executing... Can anyone recommend a graphics package that has more of the interactive 'Macintosh Cricket-graph' type functionality (geez, *any* interactivity) for use with VAX/VMS? Is everyone using SAS and SPSS?? We are a university-connected geochemical research group so cost can not be too high, but I'll listen to any suggestions. Thanks for any help. Steve Piper scripps inst. of oceanography a-020 la jolla, ca 92093 gr47%sdcc12@SDCSVAX.ARPA (ARPA/Usenet) cdrgmv::piper2 (SPAN/HEPNET) -----------------------------------------------------------------------
webber@brandx.rutgers.edu (Webber) (11/08/87)
In article <846@sdcc12.ucsd.EDU>, gr47@sdcc12.ucsd.EDU (gr47) writes: > ... > Where can I find out what the different levels of GKS correspond to > in practical terms? I am particularly interested in a package > written at U. Lowell, MA that conforms to level 2A. Can someone give > me a quick rundown on 2A and/or some refs to GKS level descriptions? Assuming you don't want to read the standard itself (ANSI standard X3.124 - 1985; American National Standards Institute; 1430 Broadway; New York, N.Y. 10018; 212-354-3300), probably the next best thing is ``Computer Graphics Programming: GKS - The Graphics Standard'' (by G. Enderle, K. Kansy, and G. Pfaff; Springer-Verlag). The basic level scheme in GKS works along two dimensions, input and output. So, ``2a'' means level ``2'' output and level ``a'' input. Roughly, level ``0'' output means that you can use the system as an output interface, but it doesn't keep track of what you have done. Level ``1'' output means that the system keeps linked lists of primitives (called segments), which you can then later refer to to do things like rotation. Level ``2'' output means that the segment memory of level ``1'' can now be shared among workstations (allowing multiple workstation systems to be run). Roughly, level ``a'' input means no input primitives. Level ``b'' input means that input is upon request only (similar to UNIX getchar()). Level ``c'' input means that input events and sampling is supported (which means that the system is now tracking the input and answering queries from the application about the state of what has happened on various input devices). In a more general setting, GKS and other graphics standards are discussed in ``Raster Graphics Handbook, 2nd Edition'' (by Conrac Division/Conrac Corporation; Van Nostrand Reinhold Company). Also of general interest is the booklet ``Standards in the Computer Graphics Industry'' (prepared and sold by: National Computer Graphics Association; 2722 Merrilee Drive; Suite 200; Fairfax, VA 22031). ------- BOB (webber@aramis.rutgers.edu ; rutgers!aramis.rutgers.edu!webber)
thom@hpfcdq.HP.COM (Tom Morrissey) (11/09/87)
> Where can I find out what the different levels of GKS correspond to > in practical terms? > Can someone give > me a quick rundown on 2A and/or some refs to GKS level descriptions? > I have looked at 'Introduction to the Graphical Kernel System G.K.S' > by Hopgood et al., 1983, but it doesn't say anything about the > different levels -- does the 1986 ed.? The Hopgood etal book you cite contains a section on levels. See section 8.6, page 124. The 2nd edition of that book doesn't contain any new information on levels. You might want to check another GKS reference book: "Computer Graphics Programming: GKS - The Graphics Standarad", G. Enderle, K. Kansy, G. Pfaff, Springer-Verlag, 1984. There is a newer edition than this. In the 1984 edition, Chapter 2, pgs 86-98 address the levels of GKS. -- Tom Morrissey. UUCP: hplabs!hpfcla!thom ARPA Internet: thom%hpfcla@hplabs.HP.COM USPS: HP/TWO, 3404 E. Harmony Rd., Bldg 1U-73, Fort Collins, CO 80525-9599 PHONE: 303-229-2869 FAX: 303-229-2692 (with attn: Tom Morrissey, MS 1U-73, x2869)