[MUSIC] Hey, so, while we got a cursory look at Gestalt principles and pre attentive attributes in the last module, it's purpose was to provide you with an overview. This module will examine more in depth one of these principles and preattentive attributes. By the end of this lesson you will be able to recognize which of the Gestalt principles are used in a visualization and why. Let's get started. [MUSIC] First let's talk about Gestalt Principles. Remember in the last module we spent time talking about the 6 Gestalt Principles. It was pretty high level and theoretical but we're just going to review them here. We're going to bring it down to examples and visualization briefly and then really do a very deep dive into one of the Gestalt Principles in particular. Just to review, the six Gestalt Principles, they are Proximity, things close together tend to be more related than things further apart. This is the one that we're going to do to deep dive in in just a moment. Second, is the Gestalt principle of Similarity. Things that look the same tend to be grouped together. The third Gestalt principle is Enclosure. It's when we perceive things to belong together when there's a boundary or an appearance of a boundary around a group. Closure is the gut feeling that we have that we should resolve ambiguity. The resolution of ambiguity works to our benefit to eliminate distracting elements from our visualization as you can see on the screen. Continuity is when we perceive something to be part of a whole, even if they are with another section. In the sketch I drew on the screen, I'm no artist. We perceived the wavy line to be continuous, even though it is broken up by the green rectangle. In this example, we don't need a row for each division. Because it's obvious that the departments go with the top level division. In fact, we can even save horizontal space by indenting the department under each division. Finally, we come to the principle of Connection. This is simply the notion that a line connects two grouped things. If we look at for example proximity, which is one of my favorites, I'd have to say I'm a geography person so I definitely I'm very interested in, in the Gestalt principle proximity. It was actually a part of this is Tobler's First Law of Geography which states that quote, everything is related to everything else, but near things are more related than distant things. And so, it's a proximity that Gestalt principle is absolutely fundamental to geographical analysis, spatial statistics, and other types of fields related to geography. It is the basis for what's known as spatial interpolation in geographic information systems. Which by the way is offered as another course by UC Davis. This particular Gestalt principle has fundamental applications, not just in visualization of course, but across a wide swath of fields. But it also could be used for example when you're doing a categorical scatter plot, and these categorical scatter plots allows you to look and see if there's any clustering that occurs based on the scatter plot that you draw. Let's take this proximity principle further into a visualization. We're going to go back to the example that we saw back in course one. The color M map. You can follow along as I bring it up on the screen. The proximity principle implies that there are more relationships to things that are closer to each other than there are to things that are further from each other. Click on the cholera analysis tab, then Snow's Analysis. Here you see that the proximity principle is at play. The darker the red, the more deaths, the largest number of deaths occurred right next to the water pump that was infested with cholera. Now, click on, Mapping the Results as I'm doing here. Then zoom and pan on the map as I'm doing, over to the water pumps to the North. If you see here there are no cholera deaths at all over there. But as you get closer to the polluted pump, the number of deaths rose. And as you get closer and closer to those polluted pumps, the numbers of death jump quite starkly. Each of these Gestalt principles can be similarly illustrated. Now what I'd like you to do is select one of the remaining five principles, locate a visualization or create one that illustrates one of these Gestalt principles, and explain why it is the principle and why it applies to the one that you chose. You can look for the on Tableau Public or some other place. But I think it's important that if you're going to do that, you should document the source of the visualization. So that we can know where it's coming from.
