OpenLayers.Control.CustomScaleLine=OpenLayers.Class(OpenLayers.Control,{maxWidth:100,topOutUnits:"km",topInUnits:"m",bottomOutUnits:"nmi",bottomInUnits:"nmi",eTop:null,eBottom:null,initialize:function(options){OpenLayers.Control.prototype.initialize.apply(this,[options]);this.displayClass=this.displayClass.replace(/CustomScaleLine/,'ScaleLine')},draw:function(){OpenLayers.Control.prototype.draw.apply(this,arguments);if(!this.eTop){this.div.style.display="block";this.div.style.position="absolute";this.eTop=document.createElement("div");this.eTop.className=this.displayClass+"Top";this.div.appendChild(this.eTop);this.eBottom=document.createElement("div");this.eBottom.className=this.displayClass+"Bottom";this.div.appendChild(this.eBottom);}
this.map.events.register('moveend',this,this.update);this.update();return this.div;},getBarLen:function(maxLen){var digits=parseInt(Math.log(maxLen)/Math.log(10));var pow10=Math.pow(10,digits);var firstChar=parseInt(maxLen/pow10);var barLen;if(firstChar>5){barLen=5;}else if(firstChar>2){barLen=2;}else{barLen=1;}
return barLen*pow10;},update:function(){var res=this.map.getResolution();if(!res){return;}
var curMapUnits=this.map.getUnits();var inches=OpenLayers.INCHES_PER_UNIT;var maxSizeData=this.maxWidth*res*inches[curMapUnits];var topUnits;var bottomUnits;if(maxSizeData>100000){topUnits=this.topOutUnits;bottomUnits=this.bottomOutUnits;}else{topUnits=this.topInUnits;bottomUnits=this.bottomInUnits;}
var topMax=maxSizeData/inches[topUnits];var bottomMax=maxSizeData/inches[bottomUnits];var topRounded=this.getBarLen(topMax);var bottomRounded=this.getBarLen(bottomMax);topMax=topRounded/inches[curMapUnits]*inches[topUnits];bottomMax=bottomRounded/inches[curMapUnits]*inches[bottomUnits];var topPx=topMax/res;var bottomPx=bottomMax/res;this.eTop.style.width=Math.round(topPx)+"px";this.eBottom.style.width=Math.round(bottomPx)+"px";this.eTop.innerHTML=topRounded+" "+topUnits;this.eBottom.innerHTML=bottomRounded+" nm";},CLASS_NAME:"OpenLayers.Control.CustomScaleLine"});