In contrast to the creative freedom of painting or graphic illustration, map design must observe rigid limitations because the locations of geographic features such as rivers, national boundaries, and coastlines are tied to reality. Map design is defined as the systematic process of arranging and assigning meaning to elements on a map for the purpose of communicating geographic knowledge in a pleasing format. During the twentieth century, standardized symbols and designs evolved for reference maps such as topographic maps. However, nonstandard maps with unique purposes must be designed within a process that encompasses creativity, experimentation, and evaluation. Careful design is crucial to map effectiveness to avoid distorted or inaccurately represented information.