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*=======================================================================
*
* WCSLIB 7.4 - an implementation of the FITS WCS standard.
* Copyright (C) 1995-2021, Mark Calabretta
*
* This file is part of WCSLIB.
*
* WCSLIB is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* WCSLIB is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with WCSLIB. If not, see http://www.gnu.org/licenses.
*
* Author: Mark Calabretta, Australia Telescope National Facility, CSIRO.
* http://www.atnf.csiro.au/people/Mark.Calabretta
* $Id: ttab2.f,v 7.4 2021/01/31 02:24:52 mcalabre Exp $
*=======================================================================
PROGRAM TTAB2
*-----------------------------------------------------------------------
*
* TTAB2 tests the -TAB routines using PGPLOT for graphical display. It
* demonstrates the nature of linear interpolation in 2 dimensions by
* contouring the interior a single 2 x 2 interpolation element as the
* values in each corner change.
*
*-----------------------------------------------------------------------
* Set up a 2 x 2 lookup table.
INTEGER K1, K2, M
PARAMETER (M = 2, K1 = 2, K2 = 2)
INTEGER K(2), MAP(2)
DOUBLE PRECISION CRVAL(2)
DATA K /K1, K2/
DATA MAP /0, 1/
DATA CRVAL /0D0, 0D0/
* Number of subdivisions on each side of the interpolation element.
INTEGER NP
REAL SCL
PARAMETER (NP = 128)
PARAMETER (SCL = 2.0/(NP-1))
INTEGER I, IM, IK, J, L, L1, L2, L3, LSTEP, STAT(NP*NP), STATUS
REAL ARRAY(NP,NP), CLEV(-10:20), LTM(6), V0, V1, W
DOUBLE PRECISION X(M,NP,NP), WORLD(M,NP,NP)
CHARACTER TEXT*80
* On some systems, such as Sun Sparc, the struct MUST be aligned
* on a double precision boundary, done here using an equivalence.
* Failure to do this may result in mysterious "bus errors".
INCLUDE 'tab.inc'
INTEGER TAB(TABLEN)
DOUBLE PRECISION DUMMY
EQUIVALENCE (TAB,DUMMY)
*-----------------------------------------------------------------------
WRITE (*, 10)
10 FORMAT (
: 'Testing WCSLIB coordinate lookup table routines (ttab2.f)',/,
: '---------------------------------------------------------')
* PGPLOT initialization.
CALL PGBEG (0, '/null', 1, 1)
CALL PGVSTD ()
CALL PGSCH (0.7)
* The viewport is slightly oversized.
CALL PGWNAD (-0.65, 1.65, -0.65, 1.65)
DO 20 L = -10, 20
CLEV(L) = 0.2*L
20 CONTINUE
LTM(1) = -SCL*(1.0 + (NP-1)/4.0)
LTM(2) = SCL
LTM(3) = 0.0
LTM(4) = -SCL*(1.0 + (NP-1)/4.0)
LTM(5) = 0.0
LTM(6) = SCL
* Set up the lookup table.
STATUS = TABPTI (TAB, TAB_FLAG, -1, 0, 0)
STATUS = TABINI(M, K, TAB)
IF (STATUS.NE.0) THEN
WRITE (*, 30) STATUS
30 FORMAT ('TABINI ERROR',I2,'.')
GO TO 999
END IF
STATUS = TABPTI (TAB, TAB_M, M, 0, 0)
DO 50 IM = 1, M
STATUS = TABPTI (TAB, TAB_K, K(IM), IM, 0)
STATUS = TABPTI (TAB, TAB_MAP, MAP(IM), IM, 0)
STATUS = TABPTD (TAB, TAB_CRVAL, CRVAL(IM), IM, 0)
DO 40 IK = 1, K(IM)
STATUS = TABPTD (TAB, TAB_INDEX, DBLE(IK-1), IM, IK)
40 CONTINUE
50 CONTINUE
* Subdivide the interpolation element.
DO 70 I = 1, NP
DO 60 J = 1, NP
X(1,J,I) = (J-1)*(K1-1.0)*SCL - 0.5 - CRVAL(1)
X(2,J,I) = (I-1)*(K2-1.0)*SCL - 0.5 - CRVAL(2)
60 CONTINUE
70 CONTINUE
* The first coordinate element is static.
STATUS = TABPTD (TAB, TAB_COORD, 0D0, 1, 0)
STATUS = TABPTD (TAB, TAB_COORD, 0D0, 3, 0)
STATUS = TABPTD (TAB, TAB_COORD, 0D0, 5, 0)
STATUS = TABPTD (TAB, TAB_COORD, 0D0, 7, 0)
* (k1,k2) = (1,1).
STATUS = TABPTD (TAB, TAB_COORD, 0D0, 2, 0)
* The second coordinate element varies in three of the corners.
DO 170 L3 = 0, 100, 20
* (k1,k2) = (2,2).
STATUS = TABPTD (TAB, TAB_COORD, 0.01D0*L3, 8, 0)
DO 160 L2 = 0, 100, 20
* (k1,k2) = (1,2).
STATUS = TABPTD (TAB, TAB_COORD, 0.01D0*L2, 6, 0)
CALL PGPAGE ()
DO 150 L1 = 0, 100, 2
* (k1,k2) = (2,1).
STATUS = TABPTD (TAB, TAB_COORD, 0.01D0*L1, 4, 0)
* Compute coordinates within the interpolation element.
STATUS = TABX2S (TAB, NP*NP, 2, X, WORLD, STAT)
IF (STATUS.NE.0) THEN
WRITE (*, 80) STATUS
80 FORMAT ('TABX2S ERROR',I2,'.')
END IF
* Start a new plot.
CALL PGBBUF ()
CALL PGERAS ()
CALL PGSCI (1)
CALL PGSLW (3)
CALL PGBOX ('BCNST', 0.0, 0, 'BCNSTV', 0.0, 0)
CALL PGMTXT ('T', 0.7, 0.5, 0.5, '-TAB coordinates: ' //
: 'linear interpolation / extrapolation in 2-D')
* Draw the boundary of the interpolation element in red.
CALL PGSCI (2)
CALL PGMOVE (-0.5, 0.0)
CALL PGDRAW ( 1.5, 0.0)
CALL PGMOVE ( 1.0, -0.5)
CALL PGDRAW ( 1.0, 1.5)
CALL PGMOVE ( 1.5, 1.0)
CALL PGDRAW (-0.5, 1.0)
CALL PGMOVE ( 0.0, 1.5)
CALL PGDRAW ( 0.0, -0.5)
* Label the value of the coordinate element in each corner.
WRITE (TEXT, '(F3.1)') 0.0
CALL PGTEXT (-0.09, -0.05, TEXT)
WRITE (TEXT, '(F4.2)') 0.01*L1
CALL PGTEXT ( 1.02, -0.05, TEXT)
WRITE (TEXT, '(F3.1)') 0.01*L2
CALL PGTEXT (-0.13, 1.02, TEXT)
WRITE (TEXT, '(F3.1)') 0.01*L3
CALL PGTEXT ( 1.02, 1.02, TEXT)
CALL PGSCI (1)
* Contour labelling: bottom.
V0 = REAL(WORLD(2,1,1))
V1 = REAL(WORLD(2,NP,1))
IF (V0.NE.V1) THEN
IF (ABS(INT((V1-V0)/0.2)).LT.10) THEN
LSTEP = 20
ELSE
LSTEP = 40
END IF
DO 90 L = -200, 300, LSTEP
W = -0.5 + 2.0*(L*0.01 - V0)/(V1 - V0)
IF (W.LT.-0.5 .OR. W.GT.1.5) GO TO 90
WRITE (TEXT, '(F4.1)') L*0.01
CALL PGPTXT (W+0.04, -0.56, 0.0, 1.0, TEXT)
90 CONTINUE
END IF
* Contour labelling: left.
V0 = REAL(WORLD(2,1,1))
V1 = REAL(WORLD(2,1,NP))
IF (V0.NE.V1) THEN
IF (ABS(INT((V1-V0)/0.2)).LT.10) THEN
LSTEP = 20
ELSE
LSTEP = 40
END IF
DO 100 L = -200, 300, LSTEP
W = -0.5 + 2.0*(L*0.01 - V0)/(V1 - V0)
IF (W.LT.-0.5 .OR. W.GT.1.5) GO TO 100
WRITE (TEXT, '(F4.1)') L*0.01
CALL PGPTXT (-0.52, W-0.02, 0.0, 1.0, TEXT)
100 CONTINUE
END IF
* Contour labelling: right.
V0 = REAL(WORLD(2,NP,1))
V1 = REAL(WORLD(2,NP,NP))
IF (V0.NE.V1) THEN
IF (ABS(INT((V1-V0)/0.2)).LT.10) THEN
LSTEP = 20
ELSE
LSTEP = 40
END IF
DO 110 L = -200, 300, LSTEP
W = -0.5 + 2.0*(L*0.01 - V0)/(V1 - V0)
IF (W.LT.-0.5 .OR. W.GT.1.5) GO TO 110
WRITE (TEXT, '(F3.1)') L*0.01
CALL PGPTXT (1.52, W-0.02, 0.0, 0.0, TEXT)
110 CONTINUE
END IF
* Contour labelling: top.
V0 = REAL(WORLD(2,1,NP))
V1 = REAL(WORLD(2,NP,NP))
IF (V0.NE.V1) THEN
IF (ABS(INT((V1-V0)/0.2)).LT.10) THEN
LSTEP = 20
ELSE
LSTEP = 40
END IF
DO 120 L = -200, 300, LSTEP
W = -0.5 + 2.0*(L*0.01 - V0)/(V1 - V0)
IF (W.LT.-0.5 .OR. W.GT.1.5) GO TO 120
WRITE (TEXT, '(F3.1)') L*0.01
CALL PGPTXT (W+0.04, 1.52, 0.0, 1.0, TEXT)
120 CONTINUE
END IF
* Draw contours for the second coordinate element.
DO 140 I = 1, NP
DO 130 J = 1, NP
ARRAY(J,I) = REAL(WORLD(2,J,I))
130 CONTINUE
140 CONTINUE
CALL PGSLW (2)
CALL PGSCI (4)
CALL PGCONT (ARRAY, NP, NP, 1, NP, 1, NP, CLEV(-10), 10,
: LTM)
CALL PGSCI (7)
CALL PGCONT (ARRAY, NP, NP, 1, NP, 1, NP, CLEV(0), 1, LTM)
CALL PGSCI (5)
CALL PGCONT (ARRAY, NP, NP, 1, NP, 1, NP, CLEV(1), 20, LTM)
CALL PGEBUF ()
150 CONTINUE
160 CONTINUE
170 CONTINUE
CALL PGEND ()
999 STATUS = TABFREE (TAB)
END
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