Convert from ISG 561 to MGS 84

[Guest]

Hi There,

I am new to the geometric conversion game and have come with a bit of a problem converting from ISG 56 1 to WGS 84.

I have easting northing values in ISG that i have converted to Latitude Longitude values in ISG which is ok although when importing these longitude latitude values in Google they are consistently incorrect.

That is they are consistently distanced say 200m from the location that they should be (200m south - 100m west).

Are there any good apps out there that will help me to convert these values or any documentation so i can find the formulas??

Any help would be greatly appreciated as i have currently hit a brick wall.

Thanks in advance.. :D