Geom.segment

Draw separate line segments/vectors/arrows.

Note

If you want arrows, then you need to provide a Scale object for both axes. See example below.

Aesthetics

x: Start of line segment.
y: Start of line segment.
xend: End of line segment.
yend: End of line segment.
color (optional): Color of line segments.

Arguments

arrow: Default behavior for Geom.segment is to draw line segments without arrows. Geom.vector is Geom.segment(arrow=true).

Examples

seals = RDatasets.dataset("ggplot2","seals")
seals[:Latb] = seals[:Lat] + seals[:DeltaLat]
seals[:Longb] = seals[:Long] + seals[:DeltaLong]
seals[:Angle] = atan2(seals[:DeltaLat], seals[:DeltaLong])

coord = Coord.cartesian(xmin=-175.0, xmax=-119, ymin=29, ymax=50)
# Geom.vector also needs scales for both axes:
xsc  = Scale.x_continuous(minvalue=-175.0, maxvalue=-119)
ysc  = Scale.y_continuous(minvalue=29, maxvalue=50)
colsc = Scale.color_continuous(minvalue=-3, maxvalue=3)

layer1 = layer(seals, x=:Long, y=:Lat, xend=:Longb, yend=:Latb, Geom.vector, color=:Angle)

plot(layer1, xsc, ysc, colsc, coord)