The map of reality is not reality. Even the best maps are imperfect. That's because they are reductions of what they represent. If a map were to represent the territory with perfect fidelity, it would no longer be a reduction and thus would no longer be useful to us.
Trek is a NASA web-based portal for exploration of Mars. This portal showcases data collected by NASA at various landing sites and features an easy-to-use browsing tool that provides layering and viewing of high resolution data.
Using charts, maps, illustrations, data visualizations, interactives, and animation, South China Morning Post’s graphics convey complex stories with intuitive insight
This map does not depict actual data. Instead, it has been carefully designed to be a diagnostic tool for evaluating the robustness of individual color schemes. Full use of this tool will benefit your map designs because colors (even very similar colors) are easy to differentiate when they appear in a nicely ordered sequence (such as a legend). The task of differentiating the colors, however, becomes much harder when the patterns on the map are complex, such as in the lower left corner of the diagnostic map.