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.
测量两点之间的距离,在一块土地上使用locator;功能检查par("plt")和par("usr")尝试,以确保纵横比y / x为1,即单位在x和y的测量是等效的。
用法----------Usage----------
airdist(ann=FALSE)
参数----------Arguments----------
参数:ann
annotate the plot with line measured and distance
注释的图线测量和距离
值----------Value----------
a list with members:
成员列表:
参数:dist
distance measured
测量距离
参数:coords
coordinates between which distance is measured
坐标之间的距离测量
(作者)----------Author(s)----------
Roger Bivand <a href="mailto:Roger.Bivand@nhh.no">Roger.Bivand@nhh.no</a>