/***
Size is 2048, 825
Origin = (-180.000000,85.000000)
Pixel Size = (0.17578125,-0.17578125)
Corner Coordinates:
Upper Left  (-180.0000000,  85.0000000) 
Lower Left  (-180.0000000, -60.0195312) 
Upper Right ( 180.0000000,  85.0000000) 
Lower Right ( 180.0000000, -60.0195312) 
Center      (   0.0000000,  12.4902344) 
***/

var mapTop = 85, mapLeft = -180, mapWidth = 360, mapHeight = -145;
var pointLat = 0, pointLon = -51;

function getWindowOffset (elem) {
    var left = 0, top = 0;
    for (parent = elem; parent; parent = parent.offsetParent) {
	left += parent.offsetLeft;
	top += parent.offsetTop;
    }
    return [left, top];
}

function mapClicked (evt) {
    var basemap = document.getElementById("worldMap");
    var offset = getWindowOffset(basemap);
    var left = evt.clientX, top = evt.clientY;
    var x = left - offset[0], y = top - offset[1];

    document.forms[0].lon.value = mapLeft + x * (mapWidth / basemap.width);
    document.forms[0].lat.value = mapTop  + y * (mapHeight / basemap.height);

    var icon = document.getElementById("worldMapFlag");

    icon.style.position	    = "absolute";
    icon.style.left	    = (left - 0) + "px";
    icon.style.top	    = (top - 16) + "px";
    icon.style.visibility   = "visible";
}