Now, I want to talk about the fact that all the visual representations that I've introduced so far, if you think about it, use position as the main visual channel to represent time. So, think about it. In timelines, the horizontal position represents time. In calendar like visualizations or heatmaps, one of the two directions represent times, or even both of them. So, all of the visual representations we discussed so far use position as a way to represent time. Now, an important question is, are there other ways to represent time? Is it desirable to represent time with different visual channels other than position? Well, there are some situations where this is useful and necessary. We actually have seen that already in one of our previous lessons. If you remember, when we talked about geographical visualization, we also talked about situations where you have both time and geography, or time and space. In that case, you are presented with a dilemma. Why? Well, because if you want to use a spatial visualization, let's say a map, now space or position is already taken by the visual representation of a map. So, it's hard for you to use position again to represent time. So, in those cases, we have seen that there are situations and there are solutions that can be used to represent time in ways that don't involve the use of position. In particular, we have seen three main solutions. We have seen animation, we have seen the use of color, and we have seen the use of trajectories and lines, and also combinations between these three solutions. For instance, one can use animation and trajectories to see how things change over time, or animation and color, and so on. So, in general, these three techniques are always available as an additional method to represent time whenever position is not available. So, now, I'm not recommending the use of these three solutions as a way to represent time if you don't have a very good reason to do it. So. In general, if you can use position to represent time, that's the best possible solution. But, as I said, there may be situations out there where you may want to use position as a way to represent something else that is not time, and when this happens, I think it's useful for you to remember that there are at least these three methods. So, these may happen somewhat often when you have spatial temporal data, but there may be other situations out there where you may want to use position to represent something else, and now you want to add time to this visual representation. These are three possible solutions. So, keep them in mind, animation, color, and trajectories.
