My question concerns the general purpose of the composer in qgis. My first idea was that with the composer you can "save" different layer combinations with different style to gain the possibility the have different "views" on the same data. However I realized when I change the map in QGIS, the information in the composer is also refreshed. To clarify my intent I want to give a small example:
Assume you have the gas stations of different companies for a country and you want to produce a map with all companies and maps containing only the gas stations of a certain company. So in the beginning I though I just create different composers to gain different maps but I somehow fail.