av/turbidity/plot.go

88 lines
2.1 KiB
Go

/*
DESCRIPTION
Plotting functions for the turbidity sensor results.
AUTHORS
Russell Stanley <russell@ausocean.org>
LICENSE
Copyright (C) 2021-2022 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package turbidity
import (
"fmt"
"math"
"gonum.org/v1/plot"
"gonum.org/v1/plot/plotter"
"gonum.org/v1/plot/vg"
)
// normalise normalises the values in the given slice to the range [0,1] inclusive.
func normalize(s []float64) []float64 {
max := -math.MaxFloat64
min := math.MaxFloat64
out := make([]float64, len(s))
if len(s) <= 1 {
return s
}
// Find the max and min values of the s.
for i := range s {
if s[i] > max {
max = s[i]
}
if s[i] < min {
min = s[i]
}
}
for i := range s {
out[i] = (s[i] - min) / (max - min)
}
return out
}
// plotToFile creates a plot with a specified name and x&y titles using the
// provided draw function, and then saves to a PNG file with filename of name.
func plotToFile(name, xTitle, yTitle string, draw func(*plot.Plot) error) error {
p := plot.New()
p.Title.Text = name
p.X.Label.Text = xTitle
p.Y.Label.Text = yTitle
err := draw(p)
if err != nil {
return fmt.Errorf("could not draw plot contents: %w", err)
}
if err := p.Save(15*vg.Centimeter, 15*vg.Centimeter, "plots/"+name+".png"); err != nil {
return fmt.Errorf("could not save plot: %w", err)
}
return nil
}
// plotterXY provides a plotter.XYs type value based on the given x and y data.
func plotterXY(x, y []float64) plotter.XYs {
xy := make(plotter.XYs, len(x))
for i := range x {
xy[i].X = x[i]
xy[i].Y = y[i]
}
return xy
}