Add a gradient legend to a plot.

Description

Add a gradient legend to a contour plot (or other plot) to indicate the range of values represented by the color palette.

Usage

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gradientLegend(valRange, color = "topo", nCol = 30, pos = 0.5, side = 4,
  length = 0.25, depth = 0.05, inside = TRUE, coords = FALSE,
  pos.num = NULL, n.seg = 3, border.col = "black", dec = NULL)

Arguments

valRange

Range of the values that is represented by the color palette. Normally two value-vector. If a larger vector is provided, only the min and max values are being used.

color

Name of color palette to use ('topo', 'terrain', 'heat', 'rainbow'). Custom color palettes can also be provided, but then the argument nCol is ignored.

nCol

Number of colors in the color palette.

pos

A number indicating the position on the axis in proportion. Using the arguments length and depth and side the position of the legend is calculated automatically. Alternatively, one could provide a vector with 4 numbers, providing the xleft, ybottom, xright, ytop of a rectangle. These 4 points are indicated in proportions of the x- and y-axis. However, if the argument coords is set to TRUE, these positions are taken as values in the Cartesian coordinate system of the plot. Note: coords is only considered for 4-number vectors of pos.

side

Which axis to choose: 1=bottom, 2=left, 3=top, 4=right. Default is 4.

length

Number, indicating the width of the legend as proportion with respect to the axis indicated by side. Note: when pos is defined by 4 numbers, length is ignored.

depth

Number, indicating the height of the legend as proportion with respect to the axis perpendicular to side. Note: when pos is defined by 4 numbers, depth is ignored.

inside

Logical: whether or not to plot the legend inside or outside the plot area. Note: when pos is defined by 4 numbers, inside is ignored.

coords

Logical: whether or not pos is defined as coordinates. When FALSE, the default, pos is defined in proportions. Note: when pos is defined by 1 number, inside is ignored. #' @param color Name of color palette to use ('topo', 'terrain', 'heat', 'rainbow'). Custom color palettes can also be provided, but then the argument nCol is ignored.

pos.num

Numeric value, indicating the position of the numbers with respect to the tick marks. 1=bottom, 2=left, 3=top, 4=right.

n.seg

Number of ticks and markers on the scale.

border.col

Color of the border and the ticks.

dec

Number of decimals for rounding the numbers, set to NULL on default (no rounding).

Author(s)

Jacolien van Rij

See Also

Other Functions for plotting: addInterval, add_bars, add_n_points, alphaPalette, alpha, check_normaldist, color_contour, dotplot_error, drawArrows, emptyPlot, errorBars, fill_area, getCoords, getFigCoords, getProps, legend_margin, marginDensityPlot, plot_error, plot_image, plotsurface

Examples

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# empty plot:
emptyPlot(1,1, main="Test plot")
gradientLegend(valRange=c(-14,14),pos=.5, side=3)
gradientLegend(valRange=c(-14,14),pos=.125, side=4, inside=FALSE)
gradientLegend(valRange=c(-14,14),pos=.75, length=.5,
color=alphaPalette('white', f.seq=seq(0,1, by=.1)), border.col='white')

# when defining custom points, it is still important to specify side:
gradientLegend(valRange=c(-14,14), pos=c(500,-5,1250,-4), coords=TRUE, 
border.col='red', side=1)

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