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Priyank edited this page Apr 7, 2017 · 19 revisions

Lines and Points

Plotutil

If the default style (color, dashes, and glyph shapes) work for you then the plotutil package makes creating line and points plots very easy:

points_simple2.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/plotutil"
	"github.com/gonum/plot/vg"
)

func main() {
	rand.Seed(int64(0))

	p, err := plot.New()
	if err != nil {
		panic(err)
	}

	p.Title.Text = "Plotutil example"
	p.X.Label.Text = "X"
	p.Y.Label.Text = "Y"

	err = plotutil.AddLinePoints(p,
		"First", randomPoints(15),
		"Second", randomPoints(15),
		"Third", randomPoints(15))
	if err != nil {
		panic(err)
	}

	// Save the plot to a PNG file.
	if err := p.Save(4*vg.Inch, 4*vg.Inch, "points.png"); err != nil {
		panic(err)
	}
}

// randomPoints returns some random x, y points.
func randomPoints(n int) plotter.XYs {
	pts := make(plotter.XYs, n)
	for i := range pts {
		if i == 0 {
			pts[i].X = rand.Float64()
		} else {
			pts[i].X = pts[i-1].X + rand.Float64()
		}
		pts[i].Y = pts[i].X + 10*rand.Float64()
	}
	return pts
}

More Detailed Style Settings

If you need more fine-grained control it is available too:

points_1.png

package main

import (
	"image/color"
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
        "github.com/gonum/plot/vg/draw"
)

func main() {
	// Get some random points
	rand.Seed(int64(0))
	n := 15
	scatterData := randomPoints(n)
	lineData := randomPoints(n)
	linePointsData := randomPoints(n)

	// Create a new plot, set its title and
	// axis labels.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Points Example"
	p.X.Label.Text = "X"
	p.Y.Label.Text = "Y"
	// Draw a grid behind the data
	p.Add(plotter.NewGrid())

	// Make a scatter plotter and set its style.
	s, err := plotter.NewScatter(scatterData)
	if err != nil {
		panic(err)
	}
	s.GlyphStyle.Color = color.RGBA{R: 255, B: 128, A: 255}

	// Make a line plotter and set its style.
	l, err := plotter.NewLine(lineData)
	if err != nil {
		panic(err)
	}
	l.LineStyle.Width = vg.Points(1)
	l.LineStyle.Dashes = []vg.Length{vg.Points(5), vg.Points(5)}
	l.LineStyle.Color = color.RGBA{B: 255, A: 255}

	// Make a line plotter with points and set its style.
	lpLine, lpPoints, err := plotter.NewLinePoints(linePointsData)
	if err != nil {
		panic(err)
	}
	lpLine.Color = color.RGBA{G: 255, A: 255}
	lpPoints.Shape = draw.PyramidGlyph{}
	lpPoints.Color = color.RGBA{R: 255, A: 255}

	// Add the plotters to the plot, with a legend
	// entry for each
	p.Add(s, l, lpLine, lpPoints)
	p.Legend.Add("scatter", s)
	p.Legend.Add("line", l)
	p.Legend.Add("line points", lpLine, lpPoints)

	// Save the plot to a PNG file.
	if err := p.Save(4*vg.Inch, 4*vg.Inch, "points.png"); err != nil {
		panic(err)
	}
}

// randomPoints returns some random x, y points.
func randomPoints(n int) plotter.XYs {
	pts := make(plotter.XYs, n)
	for i := range pts {
		if i == 0 {
			pts[i].X = rand.Float64()
		} else {
			pts[i].X = pts[i-1].X + rand.Float64()
		}
		pts[i].Y = pts[i].X + 10*rand.Float64()
	}
	return pts
}

Custom tick marks

You can override the Axis.Tick.Marker function to make your own custom tick marks. Some people like commas separating the place values of numbers:

points_commas.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/plotutil"
	"github.com/gonum/plot/vg"
)

func main() {
	rand.Seed(int64(0))

	p, err := plot.New()
	if err != nil {
		panic(err)
	}

	p.Title.Text = "Relabeling tick marks example"
	p.X.Label.Text = "X"
	p.Y.Label.Text = "Y"
	// Use a custom tick marker interface implementation with the Ticks function,
	// that computes the default tick marks and re-labels the major ticks with commas.
	p.Y.Tick.Marker = commaTicks{}

	err = plotutil.AddLinePoints(p,
		"First", randomPoints(15),
		"Second", randomPoints(15),
		"Third", randomPoints(15))
	if err != nil {
		panic(err)
	}

	// Save the plot to a PNG file.
	if err := p.Save(4*vg.Inch, 4*vg.Inch, "points_commas.png"); err != nil {
		panic(err)
	}
}

// RandomPoints returns some random x, y points.
func randomPoints(n int) plotter.XYs {
	pts := make(plotter.XYs, n)
	for i := range pts {
		if i == 0 {
			pts[i].X = rand.Float64()
		} else {
			pts[i].X = pts[i-1].X + rand.Float64()
		}
		pts[i].Y = (pts[i].X + 10*rand.Float64()) * 1000
	}
	return pts
}

type commaTicks struct{}
// Ticks computes the default tick marks, but inserts commas
// into the labels for the major tick marks.
func (commaTicks) Ticks(min, max float64) []plot.Tick {
	tks := plot.DefaultTicks{}.Ticks(min, max)
	for i, t := range tks {
		if t.Label == "" { // Skip minor ticks, they are fine.
			continue
		}
		tks[i].Label = addCommas(t.Label)
	}
	return tks
}

// AddCommas adds commas after every 3 characters from right to left.
// NOTE: This function is a quick hack, it doesn't work with decimal
// points, and may have a bunch of other problems.
func addCommas(s string) string {
	rev := ""
	n := 0
	for i := len(s) - 1; i >= 0; i-- {
		rev += string(s[i])
		n++
		if n%3 == 0 {
			rev += ","
		}
	}
	s = ""
	for i := len(rev) - 1; i >= 0; i-- {
		s += string(rev[i])
	}
	return s
}

Points with error bars

errpoints2.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/plotutil"
)

func main() {
	// Get some data.
	n, m := 5, 10
	pts := make([]plotter.XYer, n)
	for i := range pts {
		xys := make(plotter.XYs, m)
		pts[i] = xys
		center := float64(i)
		for j := range xys {
			xys[j].X = center + (rand.Float64() - 0.5)
			xys[j].Y = center + (rand.Float64() - 0.5)
		}
	}

	plt, err := plot.New()
	if err != nil {
		panic(err)
	}

	// Create two lines connecting points and error bars. For
	// the first, each point is the mean x and y value and the
	// error bars give the 95% confidence intervals.  For the
	// second, each point is the median x and y value with the
	// error bars showing the minimum and maximum values.
	mean95, err := plotutil.NewErrorPoints(plotutil.MeanAndConf95, pts...)
	if err != nil {
		panic(err)
	}
	medMinMax, err := plotutil.NewErrorPoints(plotutil.MedianAndMinMax, pts...)
	if err != nil {
		panic(err)
	}
	plotutil.AddLinePoints(plt,
		"mean and 95% confidence", mean95,
		"median and minimum and maximum", medMinMax)
	plotutil.AddErrorBars(plt, mean95, medMinMax)

	// Add the points that are summarized by the error points.
	plotutil.AddScatters(plt, pts[0], pts[1], pts[2], pts[3], pts[4])

	plt.Save(4*vg.Inch, 4*vg.Inch, "errpoints.png")
}

Bar Charts

barchart3.png

package main

import (
	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/plotutil"
	"github.com/gonum/plot/vg"
)

func main() {
	groupA := plotter.Values{20, 35, 30, 35, 27}
	groupB := plotter.Values{25, 32, 34, 20, 25}
	groupC := plotter.Values{12, 28, 15, 21, 8}

	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Bar chart"
	p.Y.Label.Text = "Heights"

	w := vg.Points(20)

	barsA, err := plotter.NewBarChart(groupA, w)
	if err != nil {
		panic(err)
	}
	barsA.LineStyle.Width = vg.Length(0)
	barsA.Color = plotutil.Color(0)
	barsA.Offset = -w

	barsB, err := plotter.NewBarChart(groupB, w)
	if err != nil {
		panic(err)
	}
	barsB.LineStyle.Width = vg.Length(0)
	barsB.Color = plotutil.Color(1)

	barsC, err := plotter.NewBarChart(groupC, w)
	if err != nil {
		panic(err)
	}
	barsC.LineStyle.Width = vg.Length(0)
	barsC.Color = plotutil.Color(2)
	barsC.Offset = w

	p.Add(barsA, barsB, barsC)
	p.Legend.Add("Group A", barsA)
	p.Legend.Add("Group B", barsB)
	p.Legend.Add("Group C", barsC)
	p.Legend.Top = true
	p.NominalX("One", "Two", "Three", "Four", "Five")

	if err := p.Save(5*vg.Inch, 3*vg.Inch, "barchart.png"); err != nil {
		panic(err)
	}
}

Functions

functions.png

package main

import (
	"image/color"
	"math"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
)

func main() {
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Functions"
	p.X.Label.Text = "X"
	p.Y.Label.Text = "Y"

	// A quadratic function x^2
	quad := plotter.NewFunction(func(x float64) float64 { return x * x })
	quad.Color = color.RGBA{B: 255, A: 255}

	// An exponential function 2^x
	exp := plotter.NewFunction(func(x float64) float64 { return math.Pow(2, x) })
	exp.Dashes = []vg.Length{vg.Points(2), vg.Points(2)}
	exp.Width = vg.Points(2)
	exp.Color = color.RGBA{G: 255, A: 255}

	// The sine function, shifted and scaled
	// to be nicely visible on the plot.
	sin := plotter.NewFunction(func(x float64) float64 { return 10*math.Sin(x) + 50 })
	sin.Dashes = []vg.Length{vg.Points(4), vg.Points(5)}
	sin.Width = vg.Points(4)
	sin.Color = color.RGBA{R: 255, A: 255}

	// Add the functions and their legend entries.
	p.Add(quad, exp, sin)
	p.Legend.Add("x^2", quad)
	p.Legend.Add("2^x", exp)
	p.Legend.Add("10*sin(x)+50", sin)
	p.Legend.ThumbnailWidth = vg.Inches(0.5)

	// Set the axis ranges.  Unlike other data sets,
	// functions don't set the axis ranges automatically
	// since functions don't necessarily have a
	// finite range of x and y values.
	p.X.Min = 0
	p.X.Max = 10
	p.Y.Min = 0
	p.Y.Max = 100

	// Save the plot to a PNG file.
	if err := p.Save(4*vg.Inch, 4*vg.Inch, "functions.png"); err != nil {
		panic(err)
	}
}

Histograms

hist.png

package main

import (
	"image/color"
	"math"
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
	"github.com/gonum/stat/distuv"
)

func main() {
	// Draw some random values from the standard
	// normal distribution.
	rand.Seed(int64(0))
	v := make(plotter.Values, 10000)
	for i := range v {
		v[i] = rand.NormFloat64()
	}

	// Make a plot and set its title.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Histogram"

	// Create a histogram of our values drawn
	// from the standard normal.
	h, err := plotter.NewHist(v, 16)
	if err != nil {
		panic(err)
	}
	// Normalize the area under the histogram to
	// sum to one.
	h.Normalize(1)
	p.Add(h)

	// The normal distribution function
	norm := plotter.NewFunction(distuv.UnitNormal.Prob)
	norm.Color = color.RGBA{R: 255, A: 255}
	norm.Width = vg.Points(2)
	p.Add(norm)

	// Save the plot to a PNG file.
	if err := p.Save(4*vg.Inch, 4*vg.Inch, "hist.png"); err != nil {
		panic(err)
	}
}

Box Plots

Vertical

boxplot.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
)

func main() {
	// Get some data to display in our plot.
	rand.Seed(int64(0))
	n := 10
	uniform := make(plotter.Values, n)
	normal := make(plotter.Values, n)
	expon := make(plotter.Values, n)
	for i := 0; i < n; i++ {
		uniform[i] = rand.Float64()
		normal[i] = rand.NormFloat64()
		expon[i] = rand.ExpFloat64()
	}

	// Create the plot and set its title and axis label.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Box plots"
	p.Y.Label.Text = "Values"

	// Make boxes for our data and add them to the plot.
	w := vg.Points(20)
	b0, err := plotter.NewBoxPlot(w, 0, uniform)
	if err != nil {
		panic(err)
	}
	b1, err := plotter.NewBoxPlot(w, 1, normal)
	if err != nil {
		panic(err)
	}
	b2, err := plotter.NewBoxPlot(w, 2, expon)
	if err != nil {
		panic(err)
	}
	p.Add(b0, b1, b2)

	// Set the X axis of the plot to nominal with
	// the given names for x=0, x=1 and x=2.
	p.NominalX("Uniform\nDistribution", "Normal\nDistribution",
		"Exponential\nDistribution")

	if err := p.Save(3*vg.Inch, 4*vg.Inch, "boxplot.png"); err != nil {
		panic(err)
	}
}

Or, the same plot using the plotutil package:

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/plotutil"
	"github.com/gonum/plot/vg"
)

func main() {
	// Get some data to display in our plot.
	rand.Seed(int64(0))
	n := 10
	uniform := make(plotter.Values, n)
	normal := make(plotter.Values, n)
	expon := make(plotter.Values, n)
	for i := 0; i < n; i++ {
		uniform[i] = rand.Float64()
		normal[i] = rand.NormFloat64()
		expon[i] = rand.ExpFloat64()
	}

	// Create the plot and set its title and axis label.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Box plots"
	p.Y.Label.Text = "Values"

	// Make boxes for our data and add them to the plot.
	err = plotutil.AddBoxPlots(p, vg.Points(20),
		"Uniform\nDistribution", uniform,
		"Normal\nDistribution", normal,
		"Exponential\nDistribution", expon)
	if err != nil {
		panic(err)
	}

	if err := p.Save(3*vg.Inch, 4*vg.Inch, "boxplot.png"); err != nil {
		panic(err)
	}
}

Horizontal

boxplot-horiz.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
)

func main() {
	// Get some data to display in our plot.
	rand.Seed(int64(0))
	n := 10
	uniform := make(plotter.Values, n)
	normal := make(plotter.Values, n)
	expon := make(plotter.Values, n)
	for i := 0; i < n; i++ {
		uniform[i] = rand.Float64()
		normal[i] = rand.NormFloat64()
		expon[i] = rand.ExpFloat64()
	}

	// Create the plot and set its title and axis label.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Horizontal box plots"
	p.X.Label.Text = "Values"

	// Make horizontal boxes for our data and add
	// them to the plot.
	w := vg.Points(20)
	b0, err := plotter.MakeHorizBoxPlot(w, 0, uniform)
	if err != nil {
		panic(err)
	}
	b1, err := plotter.MakeHorizBoxPlot(w, 1, normal)
	if err != nil {
		panic(err)
	}
	b2, err := plotter.MakeHorizBoxPlot(w, 2, expon)
	if err != nil {
		panic(err)
	}
	p.Add(b0, b1, b2)

	// Set the Y axis of the plot to nominal with
	// the given names for y=0, y=1 and y=2.
	p.NominalY("Uniform\nDistribution", "Normal\nDistribution",
		"Exponential\nDistribution")

	if err := p.Save(4*vg.Inch, 3*vg.Inch, "boxplot-horiz.png"); err != nil {
		panic(err)
	}
}

Quartile Plots

quartile.png

package main

import (
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
)

func main() {
	// Get some data to display in our plot.
	rand.Seed(int64(0))
	n := 10
	uniform := make(plotter.Values, n)
	normal := make(plotter.Values, n)
	expon := make(plotter.Values, n)
	for i := 0; i < n; i++ {
		uniform[i] = rand.Float64()
		normal[i] = rand.NormFloat64()
		expon[i] = rand.ExpFloat64()
	}

	// Create the plot and set its title and axis label.
	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Quartile plots"
	p.Y.Label.Text = "Values"

	// Make boxes for our data and add them to the plot.
	q0, err := plotter.NewQuartPlot(0, uniform)
	if err != nil {
		panic(err)
	}
	q1, err := plotter.NewQuartPlot(1, normal)
	if err != nil {
		panic(err)
	}
	q2, err := plotter.NewQuartPlot(2, expon)
	if err != nil {
		panic(err)
	}
	p.Add(q0, q1, q2)

	// Set the X axis of the plot to nominal with
	// the given names for x=0, x=1 and x=2.
	p.NominalX("Uniform\nDistribution", "Normal\nDistribution",
		"Exponential\nDistribution")

	if err := p.Save(3*vg.Inch, 4*vg.Inch, "quartile.png"); err != nil {
		panic(err)
	}
}

Bubble Plots

bubble.png

package main

import (
	"image/color"
	"math/rand"

	"github.com/gonum/plot"
	"github.com/gonum/plot/plotter"
	"github.com/gonum/plot/vg"
)

func main() {
	rand.Seed(int64(0))
	n := 10
	bubbleData := randomTriples(n)

	p, err := plot.New()
	if err != nil {
		panic(err)
	}
	p.Title.Text = "Bubbles"
	p.X.Label.Text = "X"
	p.Y.Label.Text = "Y"

	bs, err := plotter.NewBubbles(bubbleData, vg.Points(1), vg.Points(20))
	if err != nil {
		panic(err)
	}
	bs.Color = color.RGBA{R: 196, B: 128, A: 255}
	p.Add(bs)

	if err := p.Save(4*vg.Inch, 4*vg.Inch, "bubble.png"); err != nil {
		panic(err)
	}
}

// randomTriples returns some random x, y, z triples
// with some interesting kind of trend.
func randomTriples(n int) plotter.XYZs {
	data := make(plotter.XYZs, n)
	for i := range data {
		if i == 0 {
			data[i].X = rand.Float64()
		} else {
			data[i].X = data[i-1].X + 2*rand.Float64()
		}
		data[i].Y = data[i].X + 10*rand.Float64()
		data[i].Z = data[i].X
	}
	return data
}

Also see the Creating Custom Plotters page for details on how the Bubbles plotter was implemented.

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