b.oconn@cooper.cooper.EDU (Bob O'Connor ) (01/23/88)
Hi.
I'm looking for a contouring program. I'm running a water quality
program that gives me concentrations of a pollutant at nodes on a
grid (finite element). It gives me the location (x,y coordinates) and
the concentration at that location. I need to graphically display
the results. The program will have to interpolate between the grid
points and find points of equal concentration. It will also probably
have to have some kind of curve fitting feature.
If anyone out there has any programs or algorithms which can help
me I would appreciate it.
Thanks in advance.
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Bob O'Connor ihnp4!philabs!phri!cooper!b.oconn
The Cooper Union ||
cmcl2!cooper!b.oconn
kurtk@tekcae.TEK.COM (Kurt Krueger) (01/28/88)
ACM Alogorithm 531 worked fine for me. I was able to speed it up considerably by changing the bit fiddling subroutines to instrinsic functions on a VMS system. The only drawback is that it is NOT structured code and conversions to c (or even f77 with if-then-else) would be difficult. I use it in a stand alone, post processor mode.
kent@xanth.cs.odu.edu (Kent Paul Dolan) (01/28/88)
In article <945@luth.luth.se> sow@cad.luth.se (Sven-Ove Westberg) writes: >In article <1185@cooper.cooper.EDU> b.oconn@cooper.cooper.EDU (Bob O'Connor ) writes: >| >|Hi. >| >| I'm looking for a contouring program. I'm running a water quality >|program that gives me concentrations of a pollutant at nodes on a >|grid (finite element). It gives me the location (x,y coordinates) and >|the concentration at that location. I need to graphically display >|the results. The program will have to interpolate between the grid >|points and find points of equal concentration. It will also probably >|have to have some kind of curve fitting feature. >| If anyone out there has any programs or algorithms which can help >|me I would appreciate it. >| >|Thanks in advance. > >If your data is similar to those from a finite element program. Use >a postprocessor for a FE program. A good and cheap one is MOVIE.BYU >from Brigham Young University. > >Sven-Ove Westberg, CAD, University of Lulea, S-951 87 Lulea, Sweden. >UUCP: {uunet,mcvax}!enea!cad.luth.se!sow >Internet: sow@cad.luth.se Another approach that might prove fruitful: "Automated Contour Mapping Using Triangular Element Data Structures and An Interpolant Over Each Irregular Triangular Domain", Chris Gold, University of Alberta, et al., COMPUTER GRAPHICS (A Quarterly Repoirt of SIGGRAPH-ACM), Volume 11, Number 2, Summer 1977, (SIGGRAPH '77 PROCEEDINGS), page 170-175. Chris Gold's (fairly old) algorithm has a nice feature; it does not require resampling the data onto a regular grid before the contours are formed, thus preventing lots of well known and otherwise hard to avoid artifacts. A program could be written from the description, but it is probably better to try to contact the author at: C. L. Gold, Dept. of Geology, University of Alberta, Edmonton, Alberta, Canada T6G 2E1, in case he hasn't long ago moved on. Hope this helps; the movie.byu idea is also a good one; no guarantee it is still as cheap, but that package of programs used to go for the copy cost, around $100, and it is a very, very nice graphics package for scientific data display, at the least. There is also a very nice 3D package available from NCAR (National Center for Atmospheric Research) Boulder, Colorado, including countouring, but I've lost further contact information there. Kent, the man from xanth.