-- General TM lat/long to grid
-- converts latd, lond (in degrees) to e, n
-- needs 'include' file with projection parameters
-- needs zn=zone number to be specified for UTM-type system

latd={52.657570305,52.574136527}
lond={1.717921583, 1.339196666}
zn={31, 31}


include "WGS84data.txt"

k=latd*pi/180
l=lond*pi/180

k3=k-k0
k4=k+k0
am=((1+n1+1.25*n1^2+1.25*n1^3)*k3-(3*n1+3*n1^2+21/8*n1^3)*sin(k3)*cos(k4)+
(15/8*n1^2+15/8*n1^3)*sin(2*k3)*cos(2*k4)-35/24*n1^3*sin(3*k3)*cos(3*k4))*b1

v=a1/sqrt(1-e2*sin(k)^2)
r=v*(1-e2)/(1-e2*sin(k)^2)
h2=v/r-1

p=l-l0

n=am+n0+p^2*v*sin(k)*cos(k)/2+p^4*v/24*sin(k)*cos(k)^3*(5-tan(k)^2+9*h2)+
p^6*v/720*sin(k)*cos(k)^5*(61-58*tan(k)^2+tan(k)^4)
e=e0+p*v*cos(k)+p^3*v/6*cos(k)^3*(v/r-tan(k)^2)+p^5*v/120*cos(k)^5*
(5-18*tan(k)^2+tan(k)^4+14*h2-58*tan(k)^2*h2)

e:{357343.023,315191.669}
n:{5849162.885,5839912.464}