Error bars and bands#

Purpose and concepts#

errorbar draws xerr/yerr at samples; band fills between lower/upper at x positions. Errors use data units, while cap_size and stroke width are physical lengths.

Minimal complete example#

Run this file directly with laymesh validate or laymesh render; it contains its own canvas and required definitions.

1# Minimal complete example: plot.errorbar2page=canvas(size=(100mm,75mm),background="#ffffff")3p=plot(size=(86mm,62mm),x=axis(range=(0,4)),y=axis(range=(0,5)))4p.errorbar(x=[1,2,3],y=[1,3,2],yerr=[0.2,0.4,0.3])5page.add(p,offset=(7mm,6mm))

# Minimal complete example: plot.errorbar
page=canvas(size=(100mm,75mm),background="#ffffff")
p=plot(size=(86mm,62mm),x=axis(range=(0,4)),y=axis(range=(0,5)))
p.errorbar(x=[1,2,3],y=[1,3,2],yerr=[0.2,0.4,0.3])
page.add(p,offset=(7mm,6mm))

1# Minimal complete example: plot.errorbar2page=canvas(size=(100mm,75mm),background="#ffffff")3p=plot(size=(86mm,62mm),x=axis(range=(0,4)),y=axis(range=(0,5)))4p.errorbar(x=[1,2,3],y=[1,3,2],yerr=[0.2,0.4,0.3])5page.add(p,offset=(7mm,6mm))

# Minimal complete example: plot.errorbar
page=canvas(size=(100mm,75mm),background="#ffffff")
p=plot(size=(86mm,62mm),x=axis(range=(0,4)),y=axis(range=(0,5)))
p.errorbar(x=[1,2,3],y=[1,3,2],yerr=[0.2,0.4,0.3])
page.add(p,offset=(7mm,6mm))

Dependencies

examples/manual/plot-errorbar.lay

Parameters and default behavior#

Unitless geometry uses the canvas unit; unitless type and stroke sizes use pt. Explicit call parameters override inherited/theme defaults. The linked interface reference lists accepted types, choices and defaults per parameter.

Composition#

Combine a translucent band, central line and point errors for one experiment. Errors may be symmetric or separately specify lower/upper sides, with corresponding sample positions.

1page = canvas(size=(180 mm, 82 mm), background="#ffffff")2d = table(src="results.csv")3style = plot_style(font_family="DejaVu Sans", font_size=8 pt, line_width=0.6 pt)4p = plot(size=(80 mm, 65 mm), x=axis(label="Time (s)"), y=axis(label="Intensity"), style=style)5p.band(x=d["time"], lower=d["lower"], upper=d["upper"], color="#0072B2")6p.line(x=d["time"], y=d["signal"], color="#0072B2", label="Experiment")7p.scatter(x=d["time"], y=d["signal"], color="#0072B2", marker_size=3 pt)8p.errorbar(x=d["time"], y=d["signal"], yerr=d["error"], color="#0072B2")9p.hline(y=2, color="#777777", line_dash=[2 pt, 2 pt], label="Reference")10p.legend(position= top_left)11left = page.add(p, target=page.top_left, offset=(7 mm, 6 mm))12h = plot(size=(80 mm, 65 mm), x=axis(label="x"), y=axis(label="y"), style=style)13heat = h.heatmap(z=[[1,2,3,4],[2,4,6,5],[3,6,9,6],[4,5,6,4]], extent=(0,4,0,4), origin= lower, cmap="viridis")14h.colorbar(heat, label="Value")

page = canvas(size=(180 mm, 82 mm), background="#ffffff")
d = table(src="results.csv")
style = plot_style(font_family="DejaVu Sans", font_size=8 pt, line_width=0.6 pt)
p = plot(size=(80 mm, 65 mm), x=axis(label="Time (s)"), y=axis(label="Intensity"), style=style)
p.band(x=d["time"], lower=d["lower"], upper=d["upper"], color="#0072B2")
p.line(x=d["time"], y=d["signal"], color="#0072B2", label="Experiment")
p.scatter(x=d["time"], y=d["signal"], color="#0072B2", marker_size=3 pt)
p.errorbar(x=d["time"], y=d["signal"], yerr=d["error"], color="#0072B2")
p.hline(y=2, color="#777777", line_dash=[2 pt, 2 pt], label="Reference")
p.legend(position= top_left)
left = page.add(p, target=page.top_left, offset=(7 mm, 6 mm))
h = plot(size=(80 mm, 65 mm), x=axis(label="x"), y=axis(label="y"), style=style)
heat = h.heatmap(z=[[1,2,3,4],[2,4,6,5],[3,6,9,6],[4,5,6,4]], extent=(0,4,0,4), origin= lower, cmap="viridis")
h.colorbar(heat, label="Value")

1page = canvas(size=(180 mm, 82 mm), background="#ffffff")2d = table(src="results.csv")3style = plot_style(font_family="DejaVu Sans", font_size=8 pt, line_width=0.6 pt)4p = plot(size=(80 mm, 65 mm), x=axis(label="Time (s)"), y=axis(label="Intensity"), style=style)5p.band(x=d["time"], lower=d["lower"], upper=d["upper"], color="#0072B2")6p.line(x=d["time"], y=d["signal"], color="#0072B2", label="Experiment")7p.scatter(x=d["time"], y=d["signal"], color="#0072B2", marker_size=3 pt)8p.errorbar(x=d["time"], y=d["signal"], yerr=d["error"], color="#0072B2")9p.hline(y=2, color="#777777", line_dash=[2 pt, 2 pt], label="Reference")10p.legend(position= top_left)11left = page.add(p, target=page.top_left, offset=(7 mm, 6 mm))12h = plot(size=(80 mm, 65 mm), x=axis(label="x"), y=axis(label="y"), style=style)13heat = h.heatmap(z=[[1,2,3,4],[2,4,6,5],[3,6,9,6],[4,5,6,4]], extent=(0,4,0,4), origin= lower, cmap="viridis")14h.colorbar(heat, label="Value")15right = page.add(h, target=left.top_right, offset=(6 mm, 0 mm))16page.add(text(content="(a)", font_family="DejaVu Sans", font_size=9 pt), target=left.top_left)17page.add(text(content="(b)", font_family="DejaVu Sans", font_size=9 pt), target=right.top_left)

page = canvas(size=(180 mm, 82 mm), background="#ffffff")
d = table(src="results.csv")
style = plot_style(font_family="DejaVu Sans", font_size=8 pt, line_width=0.6 pt)
p = plot(size=(80 mm, 65 mm), x=axis(label="Time (s)"), y=axis(label="Intensity"), style=style)
p.band(x=d["time"], lower=d["lower"], upper=d["upper"], color="#0072B2")
p.line(x=d["time"], y=d["signal"], color="#0072B2", label="Experiment")
p.scatter(x=d["time"], y=d["signal"], color="#0072B2", marker_size=3 pt)
p.errorbar(x=d["time"], y=d["signal"], yerr=d["error"], color="#0072B2")
p.hline(y=2, color="#777777", line_dash=[2 pt, 2 pt], label="Reference")
p.legend(position= top_left)
left = page.add(p, target=page.top_left, offset=(7 mm, 6 mm))
h = plot(size=(80 mm, 65 mm), x=axis(label="x"), y=axis(label="y"), style=style)
heat = h.heatmap(z=[[1,2,3,4],[2,4,6,5],[3,6,9,6],[4,5,6,4]], extent=(0,4,0,4), origin= lower, cmap="viridis")
h.colorbar(heat, label="Value")
right = page.add(h, target=left.top_right, offset=(6 mm, 0 mm))
page.add(text(content="(a)", font_family="DejaVu Sans", font_size=9 pt), target=left.top_left)
page.add(text(content="(b)", font_family="DejaVu Sans", font_size=9 pt), target=right.top_left)

1time,signal,error,lower,upper20,0.4,0.12,0.28,0.5231,1.3,0.18,1.12,1.4842,1.9,0.15,1.75,2.0553,1.5,0.20,1.30,1.7064,2.7,0.22,2.48,2.9275,3.1,0.16,2.94,3.26

time,signal,error,lower,upper
0,0.4,0.12,0.28,0.52
1,1.3,0.18,1.12,1.48
2,1.9,0.15,1.75,2.05
3,1.5,0.20,1.30,1.70
4,2.7,0.22,2.48,2.92
5,3.1,0.16,2.94,3.26

Dependencies

examples/plot/results.csv
examples/plot/scientific.lay

Common errors and limits#

Errors cannot be negative and arrays must match. Broken-axis/projection clipping does not invent error caps. Missing inputs retain diagnostics. Bounds are not error magnitudes.

Individual functions#

plot-errorbar#

Add error bars. xerr and yerr accept symmetric errors or separate lower and upper errors; cap_size sets the physical cap length.

Returns: A layer handle that can be included in a shared legend.

Minimal complete source · Composition source · All parameters

plot-band#

Filled band layer: add data to this plot, control its appearance with physical style parameters, and select data mappings with named-axis parameters.

Returns: A layer handle that can be included in a shared legend.

Minimal complete source · Composition source · All parameters

Detailed behavior and further examples#

Parameters#

Parameter	Purpose	Default or requirement
`yerr / xerr`	Error ranges	Match observations
`lower / upper`	Band boundaries	Same length as x

Common usage#

Error bars express uncertainty per observation; band uses lower/upper bounds for intervals. The left panel combines lines, points, bands, error bars and a reference line; the right panel shows a heatmap.

Complete parameters and rules

Lines and scatter · Bars and steps · Heatmaps and contours · Multiple axes and breaks