Re: BNG Coordinates for custom maps

Ok I have currently developed 2 solutions,

1) is to send lat/lng to my tile server which then uses the Proj.4
utility to convert from Lat/Long to BNG. This works fairly well except
that the tiles don't 'link up' perfectly, this is because a Lat doesnt
'map perfectly' to a Northing, i.e. it depends on the Long coordinate
as well.

2) The second solution I have is to get ArcIMS (my mapserver) to do the
reprojections on the fly. This way the map images 'link up' perfectly
(albeit it is noticebly slower that 1). The problem with this approach
(apart from the speed difference) is that ArcIMS will not display my
raster layers.

So I figured the best way was to send back the x,y,zoom so i could work
out the 'correct' BNG coordinates for that tile.