Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/~mperrin/software/sources/arrows2.pro Дата изменения: Thu Oct 4 07:10:10 2007 Дата индексирования: Sat Mar 1 14:05:39 2014 Кодировка: Поисковые слова: hydrogen

pro arrows2,angle,xcen,ycen,thick=thick,charsize=charsize,arrowlen=arrowlen, $
color=color,NotVertex=NotVertex,Normal = normal,Data=data,font=font,$
flip=flip
;+
; NAME:
; ARROWS2
; PURPOSE:
; overplot an arrow on an image at a given position and angle.
; NOTES:
; Like Goddard's ARROWS.PRO, except this takes a user-specified angle
; rather than a FITS astrometry header. Modified from ARROWS.PRO by
; Marshall Perrin. 2004-09-29
;
; PURPOSE:
; To display "weathervane" directional arrows on an astronomical image
; EXPLANATION:
; Overlays a graphic showing orientation of North and East.
;
; CALLING SEQUENCE:
; ARROWS,h, [ xcen, ycen, ARROWLEN= , CHARSIZE= COLOR= , /DATA
; FONT=, /NORMAL, /NOTVERTEX, THICK= ]
;
; INPUTS:
; h - FITS or STSDAS header array, must include astrometry
;
; OPTIONAL INPUTS:
; xcen,ycen - numeric scalars, specifying the center position of
; arrows. Position in device units unless the /NORMALIZED
; keyword is specified. If not supplied, then ARROWS
; will prompt for xcen and ycen
;
; OPTIONAL KEYWORD INPUTS:
; arrowlen - length of arrows in terms of normal Y size of vector-drawn
; character, default = 3.5, floating point scalar
; charsize - character size, default = 2.0, floating point scalar
; color - color that the arrows and NE letters should be. Default
; value is !P.COLOR
; Data - if this keyword is set and nonzero, the input center (xcen,
; ycen) is understood to be in data coordinates
; font - IDL vector font number (1-20) to use to display NE letters.
; For example, set font=13 to use complex italic font.
; NotVertex - Normally (historically) the specified xcen,ycen indicated
; the position of the vertex of the figure. If this
; keyword is set, the xcen,ycen coordinates refer to a sort
; of 'center of mass' of the figure. This allows the
; figure to always appear with the area irregardless of
; the rotation angle.
; Normal - if this keyword is set and nonzero, the input center
; (xcen,ycen) is taken to be in normalized coordinates. The
; default is device coordinates.
; thick - line thickness, default = 2.0, floating point scalar
; OUTPUTS:
; none
; EXAMPLE:
; Draw a weathervane at (400,100) on the currently active window,
; showing the orientation of the image associated with a FITS header, hdr
;
; IDL> arrows, hdr, 400, 100
;
; METHOD:
; Uses EXTAST to EXTract ASTrometry from the FITS header. The
; directions of North and East are computed and the procedure
; ONE_ARROW called to create the "weathervane".
;
; PROCEDURES USED:
; GETROT - Computes rotation from the FITS header
; ONE_ARROW - Draw a labeled arrow
; ZPARCHECK
; REVISON HISTORY:
; written by B. Boothman 2/5/86
; Recoded with new procedures ONE_ARROW, ONE_RAY. R.S.Hill,HSTX,5/20/92
; Added separate determination for N and E arrow to properly display
; arrows irregardless of handedness or other peculiarities and added
; /NotVertex keyword to improve positioning of figure. E.Deutsch 1/10/93
; Added /DATA and /NORMAL keywords W. Landsman July 1993
; Recognize GSSS header W. Landsman June 1993
; Added /FONT keyword W. Landsman April 1995
; Modified to work correctly for COLOR=0 J.Wm.Parker, HITC 1995 May 25
; Work correctly for negative CDELT values W. Landsman Feb. 1996
; Converted to IDL V5.0 W. Landsman September 1997
; Use GETROT to compute rotation W. Landsman June 2003
; Restored /NotVertex keyword which was not working after June 2003 change
; W. Landsman January 2004
;
;
; --- Split out to arrows2.pro by M. Perrin ---
; 2006-03-23 default charsize is now !p.charsize, not 2.
;-

;On_error,2 ;Return to caller

if (N_params() LT 1) then begin
print,'Syntax - ' + $
'ARROWS, hdr, [ xcen, ycen, ARROWLEN= , CHARSIZE= COLOR= , /DATA'
print,' FONT=, /NORMAL, /NotVertex, THICK= ]'
print,' hdr - FITS header with astrometry'
return
endif ;else zparcheck,'ARROWS',h,1,7,1,'FITS header array'

if ( N_params() LT 3 ) then $
read,'Enter x, y values for center of arrows: ',xcen,ycen

if not keyword_set( THICK ) then thick = 2.0
if not keyword_set( ARROWLEN ) then arrowlen = 3.5
if (n_elements(COLOR) eq 0) then color = !P.COLOR
if not keyword_set( NotVertex ) then NotVertex=0
if ~(keyword_set(charsize)) then charsize = !p.charsize

; Derive Position Angles for North and East separately

;getrot,h,npa, cdelt,/SILENT
;sgn = 1 - 2*(cdelt[0]*cdelt[1] GT 0)
npa = angle+90
sgn = 1.0
if keyword_set(flip) then sgn=-1.0
epa = npa + sgn*90

; Make arrows reasonable size depending on device

arrowlen_dev = arrowlen*!D.y_ch_size
arrowsize = [arrowlen_dev, arrowlen_dev/3.5, 35.0] ; See one_arrow.pro

if keyword_set( NORMAL) then begin
newcen = convert_coord( xcen, ycen, /NORMAL, /TO_DEVICE)
xcent = newcen[0]
ycent = newcen[1]
endif else if keyword_set( DATA) then begin
newcen = convert_coord( xcen, ycen, /DATA, /TO_DEVICE)
xcent = newcen[0]
ycent = newcen[1]
endif else begin
xcent=xcen & ycent=ycen
endelse

; Adjust Center to 'Center of Mass' if NotVertex set
if NotVertex then begin
rot = npa/!RADEG
dRAdX = cdelt[0]*cos(rot)
dRAdY = cdelt[1]*sin(rot)
dDECdX = cdelt[0]*sin(rot)
dDECdY = cdelt[1]*cos(rot)
RAnorm = sqrt( dRAdX^2 + dRAdY^2 )
DECnorm = sqrt(dDECdX^2 + dDECdY^2 )
xcent = xcen - (dRAdX+dDECdX)/2/RAnorm*arrowsize[0]
ycent = ycen - (dRAdY+dDECdY)/2/DECnorm*arrowsize[0]
endif

; Draw arrows
one_arrow, xcent, ycent, 90+NPA, 'N', font= font, $
charsize=charsize, thick=thick, color=color, arrowsize=arrowsize
one_arrow, xcent, ycent, 90+EPA, 'E', font = font, $
charsize=charsize, thick=thick, color=color, arrowsize=arrowsize

return
end