Conversion between plotting scales: usr, cm, symbol

Give scale conversion factors of three coordinate systems in use for traditional R graphics: use, cm, symbol.

p.scales(unit = relsysize * 2.54 * min(pin), relsysize = 0.05)

Arguments

unit

length of unit (or x and y units) of symbol coordinates in cm.

relsysize

same, as a proportion of the plotting area.

Value

A numeric 2x2 matrix, with rows named x and y, and columns, named "sy2usr" and "usr2cm" which give the scale conversion factors from ‘symbol’ (as given) to ‘usr’ coordinates and from these to ‘cm’, respectively.

Author

Werner Stahel, 1990; simplification: M.Maechler, 1993, 2004

See also

par("usr"), of also ("pin") on which this is based.

Examples

p.scales()
#>   sy2usr usr2cm
#> x 0.0445   13.8
#> y 0.0500   12.3