Scatter

// This example was found at:
// www.cookbook-r.com/Graphs/Scatterplots_(ggplot2)
val rand = java.util.Random(123)
val n = 20
val dataset = dataFrameOf(
    "cond" to List(n / 2) { "A" } + List(n / 2) { "B" },
    "xvar" to List(n) { i: Int -> i },
    "yvar" to List(n) { i: Int -> i + rand.nextGaussian() * 3 }
)
val cond = "cond"<String>()
val xvar = "xvar"<Int>()
val yvar = "yvar"<Double>()

Basic Scatter Plot

plot(dataset) {
    points {
        x(xvar)
        y(yvar)
        symbol = Symbol.CIRCLE_OPEN
    }
}

plot(dataset) {
    points {
        x(xvar)
        y(yvar)
        color(cond)
        symbol(cond)
        size = 5.0
    }
    layout {
        size = 700 to 350
    }
}

plot(dataset) {
    points {
        x(xvar)
        y(yvar)
        color(cond)
        symbol(cond) {
            scale = categorical(range = listOf(Symbol.CIRCLE_OPEN, Symbol.TRIANGLE_OPEN))
        }
        size = 5.0
    }
    layout {
        size = 700 to 350
    }
}

Handling Over-plotting

// Create data with overlapping points.
val datasetOverlapping = dataset.convert { xvar and yvar }.with {
    (it.toDouble() / 5).toInt() * 5
}

plot(datasetOverlapping) {
    points {
        x(xvar) {
            axis.breaks(listOf(0, 5, 10, 15))
        }
        y(yvar)
        alpha = .3
        size = 7.0
    }
    layout {
        size = 700 to 350
    }
}

plot(datasetOverlapping) {
    points {
        x(xvar) {
            axis.breaks(listOf(0, 5, 10, 15))
        }
        y(yvar)
        symbol = Symbol.CIRCLE_OPEN

        position = Position.jitter(.1, .1)
    }
    layout {
        size = 700 to 350
    }
}

Last modified: 07 December 2023