What other ways are there to obtain sector data?

Occasionally, you will get this as a reward for certian encounters. One that springs to mind is map data for encountering a lone drone without destroying it (requires an Engi, I believe), but other encounters can also update your map data and reveal information to you as a reward.

As Zibbobz brought out, here are several random events which reward you with map data.

I haven't found a complete list on the wiki, but a quick search revealed just a few of many random events which reward you with map data of the sector.

• De-Activated Rebel Automated Scout Random Mission
• Rebel Automated Ship Near Sensor Station
• Drone guardian Rebel station
• Federation Deserters
• Zoltan Ship Tour

Most of them follow the same pattern of receiving the map data after defeating a ship, but a few have other requirements such as upgraded sensors, or (just like in the case of merchants) receiving the map data in exchange for resources.