- to obtain curve fitting equation from graph image/published graph.

- to find complex intersection points of 2 lines.

- to plot pump curves (2 identical pumps in parallel) and system curve.

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There are situations where you need to find a curve fit equation from the given graph image / published graph. Let's get stuff done in a simple yet effective way.

This app can trace an existing curve from a graph image/published graph, and obtain a curve fitting equation.

For linear-linear graph, curve fitting equations available are linear, parabolic and cubic.

For straight line on log-log graph plot, curve fitting equation is a power function.

You can copy & paste the equation for other purpose.

For details, download these how-to documentations:

Note: This app cannot do semi-log graph, or curve line on log-log graph.

This app can find complex intersection points of 2 irregular lines as shown above.

You can key-in the points for the 2 lines, or generate points from equations.

The basic built-in equations to generate points are:

- linear line: y = c * x + k

- parabolic: y = b * x^2 + c * x + k

- cubic: y = a * x^3 + b * x^2 + c * x + k

- power: y = c * x^n

The result comparison and validation can be downloaded here.

The following example shows the pump-system curves intersection point. The points are generated from the following equations:

Line 1 equation: Y = (12.1959750485299) X^0 + (-0.000313889819417844) X^1 + (-6.21374144873013E-08) X^2

Line 2 equation: Y = (0.0834768409254421) X^0 + (-0.000105670775146769) X^1 + (1.93568787397805E-07) X^2 + (-1.45541723653532E-12) X^3

This app can plot 2 identical pumps in parallel curve and system curve. See How-To example.

Final Thought: I wanted to obtain a curve fitting equation from an existing graph image, and I felt powerless to do so. So I engineered this application, and so on.

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OS Requirement: Windows Vista, 7, 8, 10, ... (does not work on Windows XP)

Purchase: USD 2.00

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