The poem is written from the perspective of a person who is observing the city from above, seeing it seated in a jet plane. As he ascends the heights in the sky, he is able to understand the real meaning of geography.
As the plane took off from the ground and went into the sky, it becomes clear why the city was developed in a certain way. From a certain height, the city started to look smaller in size. A mile was reduced to six inches on the scale. But, what looked haphazard and without logic on the ground, seemed inevitable and necessary when viewed from the sky.
When the plane attained ten thousand feet of height, the logic of geography unravelled itself. The speaker is able to comprehend that it is land and water that attract man or habitation. And therefore, many cities developed where the rivers were flowing and the valleys, too, were populated for similar reasons.
As the plane attained another six miles, it became amply clear that the earth was round and there was more water than land. However, the logic of geography failed to answer one question. The speaker was unable to understand why people hate and kill each other. Why was there a need to build walls across the cities. Even from that height, the causes behind human hatred remained unclear.