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Super Chart y-axis auto scale suggestions

#1

Hi!

Firstly, I love what you are doing with the Super Chart. It looks great and has amazing functionality. The issue for me is that the auto scaling on the y-axis can be confusing at times and it forces me to use the static y-axis scaling (the VALUES option).

Auto scaling of the y-axis (the HEIGHT, % option) is critical to many data streams since you do not know the range of your data. I have some specific suggestions that I think could enhance the scaling. Screenshot are from an iPhone 6 SE.

  1. HEIGHT, % min and max values:
    When setting min = 10 and max = 90 I get 10% of ‘air’ underneath and above my graph. This is great. The y-axis values, however, also get squeezed down, so instead of getting more air around my curve, the whole graph and y-axis is just squeezed together. In the screenshot below you can see that the temperature y-axis does not utilise the full vertical space like the (static) humidity y-axis values is doing.
    y-axis squeeze

  2. Static minimum y-axis range (maximum zoom)
    Depending on your data, there is a limit to how much you want to zoom in on the data. Eg for a temperature sensor where ± 0.3 is just sensor noise you may not want to zoom too much in on it. If you have stable readings around 20 Celsius, you may still want to see a range [20, 30] Celsius on the y-axis or even more. The screenshot below shows the extreme case in ‘live’ scope where time is short and data values are within [24.48, 24,50]. Some ideas to solve:

  • Static minimum y-axis range option. User sets a minimum y-axis range (eg. 10, which will stop y-axis zoom at [20, 30] if the middle point of the graph is at 25.
  • Pin a y-value to the x-axis and only scale upwards. Typically useful for data that goes from zero and up (for example air pollution PM2.5 values). You pin y=0 to the x-axis and scale so that y=0 and y=max_value is always in sight.

super chart y-axis close zoom

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#2

Right, when selecting Height,% option your graph is placed in the defined space range entirely - you can’t specify Values for the Y range. And this limitation is something we had discussed internally back then, but postponed due to lack of time.
Just so you understand, the main initial goal with the Height option was to be able to put a stream (say, a binary graph of when your air-conditioner is on) on the bottom (0-10%) of the chart space.

Thanks for the ideas. Will be checking these again when there is time for improvements.

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#3

@tarjes

I read through your post multiple times and I don’t understand 90% of it, sorry.

May I ask you to structure it differently?

For each case:

  1. Use case description. What are you trying to achieve, tell more about data flowing. Use real example with real data and actual known range (for example: humidity is know to be within 0-100%)
  2. How Blynk works within this use case
  3. How would you like Blynk to work in this use case
  4. If possible - screenshots, images, references, excel examples to explain item 3 above. Even a paper sketch is better than nothing.

Please avoid using special terminology. Simple language is the best way to describe the problem and solution.

Thanks!

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