Module:Ordnance Survey coordinates/sandbox: Difference between revisions

Revision as of 06:20, 16 December 2023

Revision as of 06:49, 16 December 2023

Line 510:

local phi = deg2rad ( latitude )

local lambda = deg2rad ( longitude )

local cosphi = cos ( phi )

local sinphi = sin ( phi )

Line 524 ⟶ 523:

local y1 = ny * cosphi * sinlambda

local z1 = ny * ( 1. - e1 ) * sinphi

-- the helmert transformation proper

-- Equation 3, Section 6.2, Ordnance Survey document

Line 531 ⟶ 529:

local y2 = ty + ( rz * x1 + s0 * y1 - rx * z1 )

local z2 = tz + ( -ry *x1 + rx * y1 + s0 * z1 )

-- convert cartesian coordinates to latitude and longitude

-- math in Annex B.2, of Ordnance Survey document

Line 538 ⟶ 535:

local e2 = ( aq - b2 * b2 ) / aq

lambda = atan ( y2 ,/ x2 )

local p2 = sqrt ( x2*x2 + y2*y2 )

phi = atan ( z2 ,/ p2*(1.-e2) )

local limit = 1. / b2

Line 550 ⟶ 547:

phi_alt = phi

ny = a2 / sqrt ( 1. - e2 * sin(phi) * sin(phi) )

phi = atan ( (z2 + e2 * ny * sin(phi)) ,/ p2 )

n0 = n0 - 1

until abs ( phi - phi_alt ) <= limit or n0 <= 0

Line 595 ⟶ 592:

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

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

local A = deg2rad( longitude2 -longitude_originlon0GB ) * cos(lat_rad)

local M = find_M( lat_rad )

local M0 = 0.0

if latitude_origin ~= 0 then

M0 = find_M(deg2rad( latitude_originlat0GB ))

end

Line 624 ⟶ 621:

local function LatLon2OSGB36( latlon )

local tm = LatLonOrigin2TM(latlon.lat, latlon.lon)

if not tm then return 'TM failure '..tostring(latlon.lat)..' '..tostring(latlon.lon) end

-- fix by Roger W Haworth

Line 634 ⟶ 631:

local letters = "ABCDEFGHJKLMNOPQRSTUVWXYZ"

local c1indx1 = mw.ustring.sub(letters,18-floor(grid_y/5)*5+floor(grid_x/5),1)

local c2indx2 = mw.ustring.sub(letters,21-(grid_y%5)*5+grid_x%5,1)

local c1 = mw.ustring.sub(letters,indx1,indx1)

local c2 = mw.ustring.sub(letters,indx2,indx2)

local e = mw.ustring.format('%05d', tm.easting%100000)

Line 650 ⟶ 649:

function oscoord.WGS2OSGB(frame)

local args = getArgs(frame)

return args[1]..' '..and args[2]..' '..and oscoord._WGS2OSGB(args[1],args[2]) or ''

end