stata中biplot是什么意思?biplot做出的图是表示什么意思呢?请各位大侠不吝赐教.

biplot displays a two-dimensional biplot of a dataset. A biplot simultaneously displays the observations (rows) and the relative positions of the variables (columns). Marker symbols (points) are displayed for observations and arrows are displayed for variables.
Observations are projected to two dimensions such that the distance between the observations is approximately preserved. The cosine of the angle between arrows approximates the correlation between the variables.