A seismic vessel with 2 sources and towing a single streamer is known as a "Narrow-Azimuth Towed Streamer" (or NAZ or NATS). By the early 2000s, it was accepted that this type of acquisition was useful for initial exploration but inadequate for development and production, in which wells had to be accurately positioned. This led to the development of the "Multi-Azimuth Towed Streamer" (MAZ) which tried to break the limitations of the linear acquisition pattern of a NATS survey by acquiring a combination of NATS surveys at different azimuths (see diagram). This successfully delivered increased illumination of the subsurface and a better signal to noise ratio.