Measure a distance between two points on a plot using locator; the function checks par("plt") and par("usr") to try to ensure that the aspect ratio y/x is 1, that is that the units of measurement in both x and y are equivalent.

airdist(ann=FALSE)

## Arguments

ann

annotate the plot with line measured and distance

## Value

a list with members:

dist

distance measured

coords

coordinates between which distance is measured

## Author

Roger Bivand Roger.Bivand@nhh.no

locator