ECM is demo software for planetary-scale terrain rendering. It implements Ellipsoidal Cube Maps (ECMs), as described in M. Lambers and A. Kolb, Ellipsoidal Cube Maps for Accurate Rendering of Planetary-Scale Terrain Data, Proc. Pacific Graphics (Short Papers), Sep. 2012. It consists of three parts: libecmdb, which implements the basic model and projection; ecmdb, which builds ECM databases from remote sensing data; and ecmview, which renders ECM databases interactively.