A sequence representation for maps

An easy implementable polynomial algorithm to test for isomorphism of graphs embedded in arbitrary compact surfaces (maps) is given. The map are defined algebraically by Tutte's axtom system. We produce a canonical codification of them as a sequence of 4e integers (2e if the map is orientable) where e is the number of edges. To test for isomorphism between two maps we just have to compare their codes. Some applications relying on the implementation are given.