How is the coordinate origin determined on a topographic map?
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I’m from Nanjing, and I accidentally discovered that the coordinates 0,0 on topographic maps are actually not located in Nanjing. I’d like to ask everyone: how was this origin point determined?
The coordinates on a topographic map are determined by the coordinate system used in that area.
So how is this coordinate system determined? It doesn’t seem to be in the city center!
In different coordinate systems, the coordinate origin is also different； Generally, the coordinate origin is defined based on the partition: it lies at the intersection of the central meridian and parallel in that partition ； Nanjing uses a local coordinate system, and one can only find it by going to the Land and Resources Bureau.
Where the left foot of Qi sitting in the seat in front of me touches, of course, that place is both the origin and the endpoint. Because the Earth is round. Coordinates are set by humans; since they were established in the past, it’s just right to follow those established coordinates
Hehe, what I want to know is why – is Nanjing part of some area in Anhui? :)