如何获得当前地图的当前面积、宽度和高度(相对于经纬度)?

Let's say I have a map inside a div with width x and height y with t zoom level. How can I find the area, width and height of the currently visible map?

#0

Here is the answer,

var spherical = google.maps.geometry.spherical, 
    bounds = map.getBounds(), 
    cor1 = bounds.getNorthEast(), 
    cor2 = bounds.getSouthWest(), 
    cor3 = new google.maps.LatLng(cor2.lat(), cor1.lng()), 
    cor4 = new google.maps.LatLng(cor1.lat(), cor2.lng()), 
    width = spherical.computeDistanceBetween(cor1,cor3), 
    height = spherical.computeDistanceBetween( cor1, cor4);