Bold red is a good color for basins since it likely won’t compete with other linear feature colors and is striking enough to bring attention to them. Purple is another good choice since it is close to blue on the color wheel. Blue, of course, is the color for hydrography and basins are closely related to hydrography. Any bright colors would be good as well. It is usually not necessary to use a fill color or pattern on a basin map as that would only obscure the features in the interior of the basin. However, if your map’s focus is solely on the basins themselves, without any detailed background data, you could borrow the fill technique discussed in the Political Boundaries section. For this technique, you use a series of related colors as fills. The colors need to be different enough, especially for adjacent features, to be able to tell where each basin is. When your basins are nested within each other a common practice is to use a thicker outline for the major basins and subsequently thinner lines for each tier of smaller basin size. Only use this technique if it is really called for because it could potentially create useless visual clutter. In many cases simply using the basin outlines without a fill color is plenty. The color of the outlines can be lightened for the nested basins and darkened for the major basins. To minimize confusion, however, make sure to not change the actual color. Occasionally you will run into an issue with the basin scale and the other map element scales not being entirely coincident. When the basins are of a finer scale than the rest of the map data, they can wind up looking too chunky due to having many more nodes than needed at a small scale. To fix this problem you will have to get