This is a follwup to the pre Foxy Message API review

GridCells
Are the points in cells the center point? It could use some documentation?

MapMetaData:
Is origin the center point of the (0,0) cell? Which direction do cell coordinates increase? Is (0,0) x,y in a right handed coordinate system such that (0,0) is the bottom right cell, or is it row,col such that (0,0) is the top left cell?