Take off from the very center of OSLO in Ullevål Hospital, ICAO ENUH. Made with photogrammetry in and around the hospital itself. There is one helipad for takeoff and landing, and I recommend using this pack with the "WORLD UPDATE V: NORDICS" from MSFS marketplace - to get key buildings in the city.
There is also a "OSLO Photogrammetry" to be found here in flightsim.to, if you have a very powerful computer. This covers the centrum area and all the surrounding islands. Keep in mind that this is pack is made of old photos, before Bjørvika and Sørenga was built complete, and you see a lot of cranes and unfinished buildings with this pack.
Just drop the "habibi-ulleval-scenery" in the community folder, under "C:\Users\XXXXX\AppData\Roaming\Microsoft Flight Simulator\Packages\Community" and look up ENUH ingame.