volcano_example_test.go

Documentation: gonum.org/v1/plot/plotter

     1  // Copyright ©2015 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:generate ./volcano
     6  
     7  package plotter_test
     8  
     9  import (
    10  	"image/color"
    11  
    12  	"gonum.org/v1/gonum/mat"
    13  	"gonum.org/v1/plot"
    14  	"gonum.org/v1/plot/palette"
    15  	"gonum.org/v1/plot/plotter"
    16  	"gonum.org/v1/plot/vg"
    17  	"gonum.org/v1/plot/vg/draw"
    18  )
    19  
    20  type deciGrid struct{ mat.Matrix }
    21  
    22  func (g deciGrid) Dims() (c, r int)   { r, c = g.Matrix.Dims(); return c, r }
    23  func (g deciGrid) Z(c, r int) float64 { return g.Matrix.At(r, c) }
    24  func (g deciGrid) X(c int) float64 {
    25  	_, n := g.Matrix.Dims()
    26  	if c < 0 || c >= n {
    27  		panic("index out of range")
    28  	}
    29  	return 10 * float64(c)
    30  }
    31  func (g deciGrid) Y(r int) float64 {
    32  	m, _ := g.Matrix.Dims()
    33  	if r < 0 || r >= m {
    34  		panic("index out of range")
    35  	}
    36  	return 10 * float64(r)
    37  }
    38  
    39  func Example_volcano() {
    40  	var levels []float64
    41  	for l := 100.5; l < mat.Max(volcano.Matrix.(*mat.Dense)); l += 5 {
    42  		levels = append(levels, l)
    43  	}
    44  	c := plotter.NewContour(volcano, levels, palette.Rainbow(len(levels), (palette.Yellow+palette.Red)/2, palette.Blue, 1, 1, 1))
    45  	quarterStyle := draw.LineStyle{
    46  		Color:  color.Black,
    47  		Width:  vg.Points(0.5),
    48  		Dashes: []vg.Length{0.2, 0.4},
    49  	}
    50  	halfStyle := draw.LineStyle{
    51  		Color:  color.Black,
    52  		Width:  vg.Points(0.5),
    53  		Dashes: []vg.Length{5, 2, 1, 2},
    54  	}
    55  	c.LineStyles = append(c.LineStyles, quarterStyle, halfStyle, quarterStyle)
    56  
    57  	h := plotter.NewHeatMap(volcano, palette.Heat(len(levels)*2, 1))
    58  
    59  	p := plot.New()
    60  	p.Title.Text = "Maunga Whau Volcano"
    61  
    62  	p.Add(h)
    63  	p.Add(c)
    64  
    65  	p.X.Padding = 0
    66  	p.Y.Padding = 0
    67  	_, p.X.Max, _, p.Y.Max = h.DataRange()
    68  
    69  	if err := p.Save(10*vg.Centimeter, 10*vg.Centimeter, "testdata/volcano.png"); err != nil {
    70  		panic(err)
    71  	}
    72  }
    73
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