Ageographer who works with city governments to lay out new parks and streets might be a(n)

A "geographer" who works with "city governments" to help layout new parks and streets might be a cartographer.

Explanation:

A cartographer is the one who is responsible for making precise and accurate maps of different places by studying the features and the orientation of "natural and man-made objects" at that particular place. To prepare layouts of new parks and streets already built or to be built in the city, the city government would hence need to consult a cartographer.

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