Canis River is an official skirmish map from Supreme Commander. It is a small map and is very rich on resources for a one-on-one game. The 6 mass extractors at the player's initial location, with the many rocks scattered all over the map allow the construction of large tech one armies, making a rushing strategy essential. Both players also have access to one hydrocarbon plant.
The river in the middle forces the large groups of tech 1 units to go through either of the two choke-points, one close to the player's own base, one close to the opponent's base. It's easy to defend the closest chocke point but virtually impossible to break through at the one furthest away. The river may block the path for most of the land units but it is extremely shallow so ACUs are still vulnerable if they stand in it.