| Wed Aug 27 09:17:11 2014 by Mara |
| Hi, The choice of projections and lack of definitions of what things mean is really confusing. I'm hoping that someone here will be able to guide me in the right direction. I'm probably after the holy grail but eh... I want a map that which will show 1km square exactly no matter how I orient the map. So if I look in the top left and take a 1km square and then look in the center and take a 1km square, I know that they're exactly the same. So far, the only way I can see of doing this is a globe and that's... not suitable. The reason being is that the game I'm playing uses a grid-like territory system and I don't want it to be unfair to one because one part of the map is extremely distorted. Lets say one player picks a territory at the north pole and another at the equator. The player at the equator technically has a much larger advantage because when wrapped back onto a globe, they would cover more land (I think). I've been using "Square" projection so far. I mean, I used conical previously (that was a bad idea when trying to find different areas on the map). The ability to wrap the map back to a globe is desirable too e.g. through gimp. So any recommendations or what would likely be the best choice? |
| Wed Aug 27 09:58:42 2014 by Mara |
| Turns out mostly, that the Mollweide projection does what I need it to. Now. If only there were a hexagonal grid... it seems to preserve the true amount of land a player would have. More to the Mollweide however to save me from cooking up a new thread on the matter. Is there anyway to reverse the projection from an Ellipse to a globe? |
| Wed Aug 27 16:50:32 2014 by Torben |
| There are several area-preserving projections: Mollweide, Peters and the area-preserving azimuthal. All of these will distort the map in some other way: Mollweide distorts shapes by bending them, Peters distorts shapes by stretching horisontally and compressing vertically (or vice-versa) as you get away from the 45-degree meridians. The azimuthal compresses the distance from the centre and stretches in the other dimension. For a full world map with no gaps, I think Mollweide or Peters will work best, but you should add a latitude/longitude grid to make it easier to see where the distortion is. The icosahedral projection is not area preserving, but fairly close to being so, and the distortions are fairly small. On the negative side, it has more gaps than Mollweide and Peters, that have the left/right gap only. The icosahedral map, however, is fairly well suited for a hexagonal grid. If you apply a regular hexagonal grid to a Mollweide or Peters projection, each hex will have the same area, but distances are not well represented by counting hexes: A hex on the can correspond to an area on the globe that is far from being equally high and wide. |