Figure 6.93 If you want to achieve a balance between providing the viewer with contextual detail and focusing the viewer’s attention on one particular feature, use this semi‑masked technique. To produce this map, I simply selected the basin and hydrology that I wanted to highlight, made them into new layers, and created lighter symbols for the focus area and darker symbols for the outside area. Some GIS programs allow symbol levels, which can be used for this effect as well. You can also create a transparent layer that covers the outside area to mute any of the data under