The lack of clear communication among the people and organizations constructing

The lack of clear communication among the people and

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The lack of clear communication among the people and organizations constructing parts of a system is perhaps the most common cause of complicated, confusing designs. A usable design starts with careful observations of how the tasks being supported are actually performed, followed by a design process that results in a good fit to the actual ways the tasks get performed. The technical name for this method is task analysis. The name for the entire process is human-centered design (HCD), discussed in Chapter 6. The solutions to the problem posed by my Del Mar home require the natural mappings described in Chapter 3. With six light switches
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mounted in a one-dimensional array, vertically on the wall, there is no way they can map naturally to the two-dimensional, horizontal placement of the lights in the ceiling. Why place the switches flat against the wall? Why not redo things? Why not place the switches horizontally, in exact analogy to the things being controlled, with a two-dimensional layout so that the switches can be placed on a floor plan of the building in exact correspondence to the areas that they control? Match the layout of the lights with the layout of the switches: the principle of natural mapping. You can see the result in Figure 4.5. We mounted a floor plan of the living room on a plate and oriented it to match the room. Switches were placed on the floor plan so that each switch was located in the area controlled 138 The Design of Everyday Things by that switch. The plate was mounted with a slight tilt from the horizontal to make it easy to see and to make the mapping clear: had the plate been vertical, the mapping would still be ambiguous. The plate was tilted rather than horizontal to discourage people (us or visitors) from placing objects, such as cups, on the plate: an example of an anti-affordance. (We further simplified operations by moving the sixth switch to a different location where its meaning was clear and it did not confuse, because it stood alone.) It is unnecessarily difficult to implement this spatial mapping of switches to lights: the required parts are not available. I had to hire a skilled technician to construct the wall-mounted box and install the special switches and control equipment. Builders and electricians need standardized components. Today, the switch boxes that are available to electricians are organized as rectangular boxes meant to hold a long, linear string of switches and to be mounted horizontally or vertically on the wall. To produce the appropriate spatial array, we would need a two-dimensional structure that could be mounted parallel to the floor, where the switches would be mounted on the top of the box, on the horizontal surface. The switch box should have a matrix of supports so that there can be free, relatively unrestricted placement of the switches in whatever pattern best suits the room. Ideally the box would use small switches, perhaps low-voltage switches that would control a separately
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