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[previous article] [next article]NCAR graphics is a collection of routines that display scientific data. NCAR graphics routines are available on the Gould NP1, as well as the Sun 3 and 4. FORTRAN and C programs can be written to call these routines.
Capabilities of NCAR include:
A handy features of NCAR are the shell scripts, ncargf77 and ncargcc, that compile FORTRAN or C programs using NCAR graphics. These shell scripts free the user from having to include the executable libraries needed to use NCAR routines.
NCAR routines produce output in the form of a Computer Graphics Meta-file (CGM) that can be translated into a format for various devices. This translator, called ctrans, can produce PostScript, UNIX plot standard, and Tektronix output.
NCAR provides a group of routines called autograph that do a variety of 2-d plots. A simple example is below.
autograph example shown here (ps.autograph)
% cat autograph.ex.f
C define data arrays
C
real xdra(201), ydra(201,12)
C
C initialize gks.
C
call opngks
C
C fill the data arrays.
C
do 103 i=1,201
xdra(i)= -1.+.02*float(i-1)
if( i .gt. 101) xdra(i)=2. - xdra(i)
do 101 j=1,10
ydra(i,j)=float(j)*
+ (sin(1.00000001-xdra(i)**2) \
+cos(1.00001-xdra(i)**2))/10.
if(i .gt. 101) ydra(i,j)= -ydra(i,j)
ydra(i,11)= xdra(i)
ydra(i,12)= xdra(i)*xdra(i)
101 continue
102 continue
C
C draw the graph, using EZMXY.
call ezmxy \
(xdra,ydra,201,12,201,'Autograph Example$')
C | | | | | |
C | | | | | _plot title
C | | | | | (must end in $)
C | | | | |_length of y array
C | | | |_number of curves
C | | |_length of x array
C | |_y array
C |_x array
C close GKS
C
call clsgks
C
stop
C
end
% ncargf77 autograph.ex.f -o autograph.ex
f77 autograph.ex.f -o autograph.ex \
/usr/ecn/ncar.dir/lib/libncarg.a \
/usr/ecn/ncar.dir/lib/libncarg_gks.a \
/usr/ecn/ncar.dir/lib/libncarg.a
Gould Common FORTRAN UTX/32 Release 1.2A
Copyright (c) 1987 EPCL. All Rights Reserved.
autograph.ex.f
main program
31 Lines Compiled
% autograph.ex
% ls gmeta
gmeta
% ctrans -d ps.mono gmeta > ps.autograph
% lpr -Pna -l ps.autograph
OUTPUT = "dippon" in NUC 140D (Apple LaserWriter)
%
NCAR also provides for routines to do various types of contour plots. This contour example was written by Scott Hucker.
Hucker example contour plot
shown here (ps.hucker)
% cat hucker.f
dimension q(201,201)
data tx/.3955/, ty/.9765/
C must call opngks before calling any other
C NCAR routine
call opngks
P=1.
alpha=1.
nu=.3
xmin=0.
xmax=10.
zmin=0.
zmax=10.
xd=.1
zd=0.1
imax=ifix((xmax-xmin)/xd) + 1
jmax=ifix((zmax-zmin)/zd) + 1
print*,'imax is ',imax,' jmax is ',jmax
do 10 i=1,imax
do 10 j=1,jmax
x=xmin+xd*(i-1.)
z=zmin+zd*(j-1.)
q(i,j)=-P .br
*( ( alpha*z*sin(alpha*x)*exp(-alpha*z)
% + nu*cos(alpha*x)*(1.-alpha*z)*exp(-alpha*z)+nu))
10 continue
print*,'data array is finished'
call gselnt(1)
C tick4 controls tick mark length and direction
call tick4(-12,-8,-12,-8)
C | | | |_length minor ticks Y axis
C | | |_length major ticks Y axis
C | |_length minor ticks X axis
C |_length major ticks X axis
C
call gselnt(0)
C conrec makes contours
C from a rectangular array
call conrec .br
(q,201,imax,jmax,0.,0.,0,0,0,0)
C | | | | | | | | | |_indicates desired
C | | | | | | | | | dashed line pattern
C | | | | | | | | |_extra info on plot
C | | | | | | | | (see manual)
C | | | | | | | |_scaling factor
C | | | | | | |_contour levels parameter
C | | | | | |_highest contour level
C | | | | |_lowest contour level
C | | | |_number data values Y direction
C | | |_number data values X direction
C | |_first dimension of q
C |_array to be contoured
C
call frame
C must call clsgks before ending
C program that call NCAR routines
call clsgks
end
% ncargf77 hucker.f -o hucker
f77 hucker.f -o hucker \
/usr/ecn/ncar.dir/lib/libncarg.a \
/usr/ecn/ncar.dir/lib/libncarg_gks.a \
/usr/ecn/ncar.dir/lib/libncarg.a
Gould Common FORTRAN UTX/32 Release 1.2A
Copyright (c) 1987 EPCL. All Rights Reserved.
hucker.f
main program
46 Lines Compiled
% hucker
imax is 100 jmax is 100
data array is finished
% ctrans -d ps.mono gmeta > ps.hucker
% lpr -Pna -l ps.hucker
OUTPUT = "dippon" in NUC 140D (Apple LaserWriter)
%
The next contour example shows how a sparse, irregularly spaced data set can be contoured. Also the sample program reads its data from a file.
contour2 example shown here
% cat contour2.f
C This is an example of the NCAR routine conran
C The data to be plotted is read out of a file.
C The user is prompted for the data file name.
C x y and z data needs to be in 1D arrays
real xd(5000), yd(5000),fd(5000)
C stuff needed for conran workspace arrays
C wk space has to be 13*number of points.
C (5000 is max number of points)
real wk(13*5000)
C scrarr work area needs to be resolution**2
C (see below: CALL conop2('SSZ=ON',resolution)
real scrarr(30**2 )
C iwk (integer work space) has to be 31 * max number
C of data points
integer iwk(31 * 5000)
character *23 gfilen
C read grid data: the mesh file must contain first an
C integer specifying the number of points in the file
C and then x y and z data points in three columns
write(6,*) 'Mesh file name:'
read(5,1) gfilen
1 format(a20)
idev = 8
open(idev,file=gfilen,status='old')
rewind idev
read(idev,*) ni
C the data is then put in three 1D arrays
do 11 i = 1,ni
read(idev,*) xd(i),yd(i),fd(i)
11 continue
close (idev)
C plot x y z using NCAR routine conran
C OPEN GKS, OPEN WORKSTATION OF TYPE 1,
C ACTIVATE WORKSTATION
CALL OPNGKS
C set resolution default is 40 for a dense data set
CALL conop2('SSZ=ON',30 )
C set contour increment by default NCAR calculates
CALL conop3('CIL=ON',.01,1)
C title for plot
CALL conop4('TLE=ON','Conran Example',14,0)
C Call the routine conran to make the contour plot
CALL conran(xd,yd,fd,ni,wk,iwk,scrarr)
C frame in the plot
CALL frame
C DEACTIVATE AND CLOSE WORKSTATION, CLOSE GKS.
CALL CLSGKS
stop
end
%
% ncargf77 contour2.f -o contour2
f77 contour2.f -o contour2 \
/usr/ecn/ncar.dir/lib/libncarg.a \
/usr/ecn/ncar.dir/lib/libncarg_gks.a \
/usr/ecn/ncar.dir/lib/libncarg.a
Gould Common FORTRAN UTX/32 Release 1.2A
Copyright (c) 1987 EPCL. All Rights Reserved.
contour2.f
main program
49 Lines Compiled
%
% contour2
Mesh file name:
contour2.data
%
%
% ctrans -d ps.mono gmeta > ps.contour2
% lpr -Pna -l ps.contour2
OUTPUT = "dippon" in NUC 140D (Apple LaserWriter)
%
NCAR manuals are for sale in the Armory bookstore. ECN #734 NCAR--Autograph, A Graphics Utility sells for $5.95 and ECN #735 NCAR, User's Guide is $17.75. Questions concerning the use of NCAR or problems that arise with usage can be E-mailed to "ncar".
NOTE: In this article the postscript file was sized using the scale factor .13 or .15 to fit in a two column format.
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