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POReducing flicker in a real-time graph?
 

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  1. POReducing flicker in a real-time graph?
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    <p>I am rendering a scatter plot every 5 seconds where the X-axis denotes time and Y-axis denotes a set of names ordered alphabetically. </p> <p><img src="https://i.stack.imgur.com/RR8AO.png" alt="mockup"></p> <p>A set of data points (say, 'X's) can optionally be grouped into a category and so I use a color to show this. Therefore all 'X's with the same color belong to the same category and so on. </p> <p><strong>Problem</strong>: I have tens of thousands of 'Name's and they can appear randomly on the graph at some point in time. The real purpose is to provide the user with a graph that provides the ability to monitor these names. Therefore, every time I render the graph, I get the list of points to be rendered and the underlying <a href="http://www.humblesoftware.com/flotr2/" rel="nofollow noreferrer">graph library: Flotr2</a> takes care of assigning colors to the sets of points. Therefore, if the dataset contains two categories of points, it assigns two colors and if a point belonging to a new category arrives, it assigns a third color. As a result of this, what I am observing due to this is a flicker effect:</p> <p><img src="https://i.stack.imgur.com/EuoG5.png" alt="mockup"></p> <p>And when the point disappears, the colors revert back to the ones before. Is there a good way to solve this problem? I have two specific problems:</p> <ul> <li>Colors keep changing for every new point being added</li> <li>A new point added somewhere shifts every other point vertically in either direction. For instance, if Category 2.5 is added, it ends up shifting Category 2 down and Category 1 up because the alphabetical order should be preserved.</li> </ul> <p>In a scenario which is highly dynamic, such a graph tends to be useless because of the dynamism it shows visually. One obvious solution I can think of is to pre-allocate space for all points and all categories possible in the graph so that an appearance of a new point will not change anything but it just draws a point somewhere. However, I am not clear if this approach is ideal for large data sets where the set of names and categories change often. </p> <p>Is there a good way to solve this problem? I am open to other graph types that mitigate this problem. In short, I want a real-time display that is capable of showing the appearance of new names on a time axis.</p>
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    1. PTQuestion
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    1. USLegend
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      1. VTUpMod
    1. COUse a scrolling log or a Gantt chart.
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      1. POReducing flicker in a real-time graph?
      1. USDeer Hunter
    2. CO@DeerHunter: +1 Thank you. Can you kindly elaborate on how to address this using Gantt charts?
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      1. USLegend
    3. COWhat you have is a data reduction problem. Human beings are not accustomed to deal with scores of new pieces of data. Only if you reduce the number of names/categories to manageable proportions (not larger than 8-10) can Gantt or any other timeline based chart be useable (and each category's color should be consistently the same all the time). Try to think in terms of decision-making workflow of your users - they aren't machines, their cognition capabilities are very limited.
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