fix bug in computation of the nb of tiles
fix bug in computation of the nb of tiles

dyoussef/s2p,dyoussef/s2p,mnhrdt/s2p,carlodef/s2p,jmichel-otb/s2p,dyoussef/s2p,dyoussef/s2p,carlodef/s2p,MISS3D/s2p,MISS3D/s2p,jmichel-otb/s2p,MISS3D/s2p,MISS3D/s2p,mnhrdt/s2p,jmichel-otb/s2p,jmichel-otb/s2p