Rivers and streams, also called “hydrography,” can be simple features to display if you adhere to some common conventions such as the almost exclusive use of blue to depict them and the use of lines instead of polygons for most maps. (See Figure 6.6 for color suggestions.) Therefore, you can simply slap on a line‑based river dataset, color it blue, and go. No, it can’t be that easy. Here are some additional considerations. To start, in many cases it is wise to match the stream line colors with the same color you are using for other water bodies on your map, including oceans and lakes. Other things to think about are how to show hierarchy, attributes, and labels. These are discussed next.