Module:Ordnance Survey coordinates/sandbox: Difference between revisions

Revision as of 12:54, 17 December 2023

Revision as of 13:07, 17 December 2023

Line 528:

local function find_M ( lat_rad )

local e = OSGBglobe.ecc

local e2 = e*e

local e3 = e*e*e

return OSGBglobe.semimajor * ( ( 1 - e/4 - 3 * e * ee2/64

- 5 * e * e * ee3/256

) * lat_rad

- ( 3 * e/8 + 3 * e * ee2/32

+ 45 * e * e * ee3/1024

) * sin(2 * lat_rad)

+ ( 15 * e * ee2/256 +

45 * e * e * ee3/1024

) * sin(4 * lat_rad)

- ( 35 * e * e * ee3/3072

) * sin(6 * lat_rad) )

end

Line 561 ⟶ 563:

local v = OSGBglobe.semimajor / sqrt(1 - e * sin(lat_rad)*sin(lat_rad))

local Ttank = pow( tan(lat_rad), 2)

local T = tank*tank

local T2 = T*T

local C = e_prime_sq * pow( cos(lat_rad), 2)

local A = deg2rad( longitude2 -OSGBglobe.lon0 ) * cos(lat_rad)

local A2 = A*A

local A3 = A2*A

local A4 = A2*A2

local A5 = A3*A2

local A6 = A3*A3

local M = find_M( lat_rad )

local M0 = 0.0

Line 572 ⟶ 581:

local northing = OSGBglobe.n0 + OSGBglobe.scale *

( (M - M0) + v*tan(lat_rad) *

( A*AA2/2

+ (5 - T + 9*C + 4*C*C) * pow(A,4)A4/24

+ (61 - 58*T + T*T T2

+ 600*C - 330*e_prime_sq) * pow(A,6)A6/720 ))

local easting = OSGBglobe.e0 + OSGBglobe.scale * v *

( A

+ (1-T+C)*pow(A,3)A3/6

+ (5 - 18*T + pow(T,2)T2 + 72*C

- 58 * e_prime_sq)*pow(A,5)A5/120 )

return {northing=northing,easting=easting}