but that's the problem with any map. It's a 2D representation of a 3D thing. The other thing you forget is that *****y little thing called gravity. Stellar bodies are not static. They drift over time. The other thing is that the 3D to 2D shift distorts something (Greenland on most maps)
the Lay out is correct probably on the map, so while looking down on the NJO map it is probably right but it's relationship in 3D (x,y,z) isn't.
also, i believe the use of the word system is defined by most star wars sources is a solar system (the planets orbiting a star(s), since binary systems in science are more abundant than unitary or trinary). A sector is probably the 5 by 5 by 5 light year volume. That would allow for something like Corellia to be the system with Corellia, Drall, Sacoria, Talus and Tralus and the Correllian Sector to include those, Duro, Sacoria etc.