of the isolated chaotic map is greater than some critical positive value. We propose a few schemes that make spatial synchronization possible in large lattices. If the idea of only local connections is abandoned, the number of connections necessary for synchronization dramatically decreases to three per node. We also propose a model of a lattice with an external pacemaker, where we find a spatially homogeneous mode synchronous with the pacemaker, as well as different from the pacemaker mode.
