The palette
Almost everything here is line: the water is thin, the green comes in patches, and the grid itself is the picture. Give the major streets a clearly darker line than the rest, so that the squares of a mile read across the whole sheet, and keep a light line for the minor streets, so that each square holds its own texture. Water needs an ink strong enough to show in the lagoons of Encanto Park and in the thin line of the river; for the green, parks and riverbanks, a soft tint is enough.