I wanted to say that the lake is in the northern part of the city. As 北部 means the northern part, I naturally thought that 湖在城市的北部 would be a correct way of putting it. But some people said that 湖在城市的北边 is the correct answer. As I know that 北边 can also be used to mean the northern part for architectural regions like campus, which also seems to apply to cities, now I am not so sure which one I have to use. Do I have to use 北边 or 北部?
My question was more specific. 湖在城市的北部 would mean like that the lake is actually inside the city, but in the northern part of the city. 北边 means north, so I thought that saying 湖在城市的北边 would mean that the lake is to the north of the city, and outside the city. However, I learned that 北边 can also denote that something is inside a specific region if it is talking about an architectural region, which was why I was confused.
So in summary, I was asking if I have to use 北部 or 北边 in this sentence to mean that the lake is in the city, but in the northern part of the city.