2 replies to this topic

[woneil]

Some GIS and mapping software I am familiar with can make maps that extend across the 180 deg meridian very simply from conventional -180 to +180 deg data sets. Is Manifold able to do this? I haven't been able to find out how. When I re-project such a drawing or surface with a center at, say, 165 deg, everything east of 180 deg comes out blank. Of course it is possible to take -180 to +180 deg data sets apart and put them back together as, say, 0 to +180 to -180 to 0 deg data sets, but I'd like to find a simpler way if I can, since I often have need of Pacific-oriented maps.

(Note: I also posted this question on the Manifold forum.)

[Nick Springer]

I ran into this same problem in Manifold and also posted to the Manifold forum. THe short answer is: it can't do it (unless somethign has changed). It's definitely a limitation. It also has problems with any links that cross the 180 line (they end up drawing across the whole map).

[Hans van der Maarel]

I did this with rasters and it sort of worked. A raster image that crosses the 180 degrees boundary gets drawn entirely on one side of the map. Not sure what the algorithm behind it is.