Which feature is NOT one of the six colors on a map?

The feature that is not one of the standard six colors typically used on a map is purple. In cartography, colors are often employed to convey different types of information. For example, black is frequently used for text and boundaries, green indicates vegetation or parks, and red is commonly used for roads and highways. These colors help to distinguish various features and make the map easier to interpret. Purple, while it may be used in some contexts, is not one of the foundational colors recognized in the conventional color-coding of maps, which generally include colors like blue for water, brown for elevation, green for land cover, red for roads, black for infrastructure, and yellow for urban areas. This helps users navigate and understand the map's contents effectively.