Select sun azimuth by grip

[Marcin O]

Hello,

 

I would like to select sun azimuth by block grip on my drawing.

1. I created a block with two grips (attached DWG)

2. LISP definition that gives an array of hour:minute and azimuth (radians).

 

So I need to update the value of attribute TIME1 and TIME2 when my grip changes. My problem can be probably solved by reactor. There is also a problem that the sun azimuth is defined from the north. Angle for grips in my block are defined in different way so i need to recalculate my azimuths.

 

I appreciate any responce.

 

Greetings

Marcin

 

 

(defun c:sun-azimuth-array ( / lat lon year month day jd jc gmst lst ha decl azimuth time-list)
  ;; Utility functions
  (defun deg-to-rad (deg) (* pi (/ deg 180.0)))
  (defun rad-to-deg (rad) (* 180.0 (/ rad pi)))
  (defun mod (a b) (- a (* b (fix (/ a b)))))
  
  ;; Inverse sine function
  (defun asin (x)
    (atan (/ x (sqrt (- 1 (* x x)))))
  )

  ;; Tangent function
  (defun tan (x)
    (/ (sin x) (cos x))
  )

  ;; Function to calculate Julian Date
  (defun julian-date (year month day hour minute second)
    (setq a (fix (/ (- 14 month) 12)))
    (setq y (+ year 4800 a))
    (setq m (+ month (* 12 a) -3))
    (+ day
       (/ (- (* 153 (+ m 1)) 2) 5)
       (* 365 y)
       (/ y 4)
       (/ (- y 100) 100)
       (/ y -400)
       -32045
       (/ (+ hour (/ minute 60.0) (/ second 3600.0)) 24.0)
    )
  )

  ;; Function to calculate Sun Azimuth
  (defun sun-azimuth (lat lon jd)
    ;; Calculate Julian Century
    (setq jc (/ (- jd 2451545.0) 36525.0))

    ;; Calculate Greenwich Mean Sidereal Time
    (setq gmst (mod (+ 280.46061837 (* 360.98564736629 (- jd 2451545.0)) (* 0.000387933 (* jc jc)) (/ (* jc jc jc) -38710000.0)) 360.0))

    ;; Local Sidereal Time
    (setq lst (mod (+ gmst (rad-to-deg lon)) 360.0))

    ;; Calculate Mean Anomaly of the Sun
    (setq m (mod (+ 357.5291 (* 35999.0503 jc)) 360.0))

    ;; Calculate Mean Longitude of the Sun
    (setq l0 (mod (+ 280.46646 (* 36000.76983 jc) (* 0.0003032 (* jc jc))) 360.0))

    ;; Calculate Ecliptic Longitude of the Sun
    (setq c (+ (* (sin (deg-to-rad m)) 1.914602) (* (sin (deg-to-rad (* 2 m))) 0.019993) (* (sin (deg-to-rad (* 3 m))) 0.000289)))
    (setq lambda (+ l0 c))

    ;; Calculate Declination of the Sun
    (setq eps (deg-to-rad (+ 23.439 (- (* 0.00000036 jc)))))
    (setq decl (asin (* (sin eps) (sin (deg-to-rad lambda)))))

    ;; Calculate Hour Angle
    (setq ha (- lst (rad-to-deg lambda)))

    ;; Convert Hour Angle and Latitude to Radians
    (setq ha (deg-to-rad ha))

    ;; Calculate Azimuth in Radians
    (setq azimuth (atan (/ (sin ha) (- (* (cos ha) (sin lat)) (* (tan decl) (cos lat))))))

    azimuth
  )

  ;; User inputs
  (setq lat (deg-to-rad (getreal "\nEnter latitude: ")))
  (setq lon (deg-to-rad (getreal "\nEnter longitude: ")))
  (setq year (getint "\nEnter year: "))
  (setq month (getint "\nEnter month: "))
  (setq day (getint "\nEnter day: "))

  ;; Initialize the list
  (setq time-list '())

  ;; Loop through each minute from 6:00 to 18:00
  (setq hour 6)
  (while (<= hour 18)
    (setq minute 0)
    (while (< minute 60)
      ;; Calculate Julian Date for the current time
      (setq jd (julian-date year month day hour minute 0))
      
      ;; Calculate Sun Azimuth
      (setq azimuth (sun-azimuth lat lon jd))
      
      ;; Create the time string and append to the list
      (setq time-str (strcat (itoa hour) ":" (if (< minute 10) (strcat "0" (itoa minute)) (itoa minute))))
      (setq time-list (append time-list (list (strcat time-str " " (rtos azimuth 2 6)))))
      
      ;; Increment minute
      (setq minute (+ minute 1))
    )
    ;; Increment hour
    (setq hour (+ hour 1))
  )

  ;; Print the list of time and azimuth values
  (foreach item time-list
    (prompt (strcat "\n" item))
  )

  (princ)
)

 

LS.dwg