The palette
The subject is an outline, the island's, and the first requirement is that it be visible: take the water frank and deep enough that the shape closes in one piece, western tip included. Then comes the hill, and one point needs making plain. There is only one vegetation ink, the same for every green on the sheet: you cannot give the mountain a colour that sets it apart from the parks. It sets itself apart another way, and that is more than enough, since it is the one green mass of that size caught inside the continuous built fabric, while the others line the northern river, at the edge. So give the green a value strong enough to hold everywhere, and the hill will stand out on its own. The built fabric is better kept to a single value: the grids already tilt from one neighbourhood to the next, and that is movement enough.