root/trunk/openlayers/lib/OpenLayers/Util.js

/* Copyright (c) 2006-2011 by OpenLayers Contributors (see authors.txt for 
 * full list of contributors). Published under the Clear BSD license.  
 * See http://svn.openlayers.org/trunk/openlayers/license.txt for the
 * full text of the license. */

/**
 * @requires OpenLayers/BaseTypes.js
 * @requires OpenLayers/BaseTypes/Bounds.js
 * @requires OpenLayers/BaseTypes/Element.js
 * @requires OpenLayers/BaseTypes/LonLat.js
 * @requires OpenLayers/BaseTypes/Pixel.js
 * @requires OpenLayers/BaseTypes/Size.js
 * @requires OpenLayers/Console.js
 * @requires OpenLayers/Lang.js
 */

/**
 * Namespace: Util
 */
OpenLayers.Util = OpenLayers.Util || {};

/** 
 * Function: getElement
 * This is the old $() from prototype
 *
 * Parameters:
 * e - {String or DOMElement or Window}
 * Return:
 * {Array(DOMElement)}
 */
OpenLayers.Util.getElement = function() {
    var elements = [];

    for (var i=0, len=arguments.length; i<len; i++) {
        var element = arguments[i];
        if (typeof element == 'string') {
            element = document.getElementById(element);
        }
        if (arguments.length == 1) {
            return element;
        }
        elements.push(element);
    }
    return elements;
};

/**
 * Function: isElement
 * A cross-browser implementation of "e instanceof Element".
 *
 * Parameters:
 * o - {Object} The object to test.
 *
 * Returns:
 * {Boolean}
 */
OpenLayers.Util.isElement = function(o) {
    return !!(o && o.nodeType === 1);
};

/**
 * Function: isArray
 * Tests that the provided object is an array.
 * This test handles the cross-IFRAME case not caught
 * by "a instanceof Array" and should be used instead.
 * 
 * Parameters:
 * a - {Object} the object test.
 * 
 * Returns
 * {Boolean} true if the object is an array.
 */
OpenLayers.Util.isArray = function(a) {
    return (Object.prototype.toString.call(a) === '[object Array]');
};

/** 
 * Maintain existing definition of $.
 */
if(typeof window.$  === "undefined") {
    window.$ = OpenLayers.Util.getElement;
}

/** 
 * Function: removeItem
 * Remove an object from an array. Iterates through the array
 *     to find the item, then removes it.
 *
 * Parameters:
 * array - {Array}
 * item - {Object}
 * 
 * Return
 * {Array} A reference to the array
 */
OpenLayers.Util.removeItem = function(array, item) {
    for(var i = array.length - 1; i >= 0; i--) {
        if(array[i] == item) {
            array.splice(i,1);
            //break;more than once??
        }
    }
    return array;
};

/**
 * Function: clearArray
 * *Deprecated*. This function will disappear in 3.0.
 * Please use "array.length = 0" instead.
 * 
 * Parameters:
 * array - {Array}
 */
OpenLayers.Util.clearArray = function(array) {
    OpenLayers.Console.warn(
        OpenLayers.i18n(
            "methodDeprecated", {'newMethod': 'array = []'}
        )
    );
    array.length = 0;
};

/** 
 * Function: indexOf
 * Seems to exist already in FF, but not in MOZ.
 * 
 * Parameters:
 * array - {Array}
 * obj - {*}
 * 
 * Returns:
 * {Integer} The index at, which the first object was found in the array.
 *           If not found, returns -1.
 */
OpenLayers.Util.indexOf = function(array, obj) {
    // use the build-in function if available.
    if (typeof array.indexOf == "function") {
        return array.indexOf(obj);
    } else {
        for (var i = 0, len = array.length; i < len; i++) {
            if (array[i] == obj) {
                return i;
            }
        }
        return -1;   
    }
};



/**
 * Function: modifyDOMElement
 * 
 * Modifies many properties of a DOM element all at once.  Passing in 
 * null to an individual parameter will avoid setting the attribute.
 *
 * Parameters:
 * element - {DOMElement} DOM element to modify.
 * id - {String} The element id attribute to set.
 * px - {<OpenLayers.Pixel>} The left and top style position.
 * sz - {<OpenLayers.Size>}  The width and height style attributes.
 * position - {String}       The position attribute.  eg: absolute, 
 *                           relative, etc.
 * border - {String}         The style.border attribute.  eg:
 *                           solid black 2px
 * overflow - {String}       The style.overview attribute.  
 * opacity - {Float}         Fractional value (0.0 - 1.0)
 */
OpenLayers.Util.modifyDOMElement = function(element, id, px, sz, position, 
                                            border, overflow, opacity) {

    if (id) {
        element.id = id;
    }
    if (px) {
        element.style.left = px.x + "px";
        element.style.top = px.y + "px";
    }
    if (sz) {
        element.style.width = sz.w + "px";
        element.style.height = sz.h + "px";
    }
    if (position) {
        element.style.position = position;
    }
    if (border) {
        element.style.border = border;
    }
    if (overflow) {
        element.style.overflow = overflow;
    }
    if (parseFloat(opacity) >= 0.0 && parseFloat(opacity) < 1.0) {
        element.style.filter = 'alpha(opacity=' + (opacity * 100) + ')';
        element.style.opacity = opacity;
    } else if (parseFloat(opacity) == 1.0) {
        element.style.filter = '';
        element.style.opacity = '';
    }
};

/** 
 * Function: createDiv
 * Creates a new div and optionally set some standard attributes.
 * Null may be passed to each parameter if you do not wish to
 * set a particular attribute.
 * Note - zIndex is NOT set on the resulting div.
 * 
 * Parameters:
 * id - {String} An identifier for this element.  If no id is
 *               passed an identifier will be created 
 *               automatically.
 * px - {<OpenLayers.Pixel>} The element left and top position. 
 * sz - {<OpenLayers.Size>} The element width and height.
 * imgURL - {String} A url pointing to an image to use as a 
 *                   background image.
 * position - {String} The style.position value. eg: absolute,
 *                     relative etc.
 * border - {String} The the style.border value. 
 *                   eg: 2px solid black
 * overflow - {String} The style.overflow value. Eg. hidden
 * opacity - {Float} Fractional value (0.0 - 1.0)
 * 
 * Returns: 
 * {DOMElement} A DOM Div created with the specified attributes.
 */
OpenLayers.Util.createDiv = function(id, px, sz, imgURL, position, 
                                     border, overflow, opacity) {

    var dom = document.createElement('div');

    if (imgURL) {
        dom.style.backgroundImage = 'url(' + imgURL + ')';
    }

    //set generic properties
    if (!id) {
        id = OpenLayers.Util.createUniqueID("OpenLayersDiv");
    }
    if (!position) {
        position = "absolute";
    }
    OpenLayers.Util.modifyDOMElement(dom, id, px, sz, position, 
                                     border, overflow, opacity);

    return dom;
};

/**
 * Function: createImage
 * Creates an img element with specific attribute values.
 *  
 * Parameters:
 * id - {String} The id field for the img.  If none assigned one will be
 *               automatically generated.
 * px - {<OpenLayers.Pixel>} The left and top positions.
 * sz - {<OpenLayers.Size>} The style.width and style.height values.
 * imgURL - {String} The url to use as the image source.
 * position - {String} The style.position value.
 * border - {String} The border to place around the image.
 * opacity - {Float} Fractional value (0.0 - 1.0)
 * delayDisplay - {Boolean} If true waits until the image has been
 *                          loaded.
 * 
 * Returns:
 * {DOMElement} A DOM Image created with the specified attributes.
 */
OpenLayers.Util.createImage = function(id, px, sz, imgURL, position, border,
                                       opacity, delayDisplay) {

    var image = document.createElement("img");

    //set generic properties
    if (!id) {
        id = OpenLayers.Util.createUniqueID("OpenLayersDiv");
    }
    if (!position) {
        position = "relative";
    }
    OpenLayers.Util.modifyDOMElement(image, id, px, sz, position, 
                                     border, null, opacity);

    if (delayDisplay) {
        image.style.display = "none";
        function display() {
            image.style.display = "";
            OpenLayers.Event.stopObservingElement(image);
        }
        OpenLayers.Event.observe(image, "load", display);
        OpenLayers.Event.observe(image, "error", display);
    }
    
    //set special properties
    image.style.alt = id;
    image.galleryImg = "no";
    if (imgURL) {
        image.src = imgURL;
    }
        
    return image;
};

/**
 * Function: setOpacity
 * *Deprecated*.  This function has been deprecated. Instead, please use 
 *     <OpenLayers.Util.modifyDOMElement> 
 *     or 
 *     <OpenLayers.Util.modifyAlphaImageDiv>
 * 
 * Set the opacity of a DOM Element
 *     Note that for this function to work in IE, elements must "have layout"
 *     according to:
 *     http://msdn.microsoft.com/workshop/author/dhtml/reference/properties/haslayout.asp
 *
 * Parameters:
 * element - {DOMElement} Set the opacity on this DOM element
 * opacity - {Float} Opacity value (0.0 - 1.0)
 */
OpenLayers.Util.setOpacity = function(element, opacity) {
    OpenLayers.Util.modifyDOMElement(element, null, null, null,
                                     null, null, null, opacity);
};

/**
 * Property: IMAGE_RELOAD_ATTEMPTS
 * {Integer} How many times should we try to reload an image before giving up?
 *           Default is 0
 */
OpenLayers.IMAGE_RELOAD_ATTEMPTS = 0;

/**
 * Property: alphaHackNeeded
 * {Boolean} true if the png alpha hack is necessary and possible, false otherwise.
 */
OpenLayers.Util.alphaHackNeeded = null;

/**
 * Function: alphaHack
 * Checks whether it's necessary (and possible) to use the png alpha
 * hack which allows alpha transparency for png images under Internet
 * Explorer.
 * 
 * Returns:
 * {Boolean} true if the png alpha hack is necessary and possible, false otherwise.
 */
OpenLayers.Util.alphaHack = function() {
    if (OpenLayers.Util.alphaHackNeeded == null) {
        var arVersion = navigator.appVersion.split("MSIE");
        var version = parseFloat(arVersion[1]);
        var filter = false;
    
        // IEs4Lin dies when trying to access document.body.filters, because 
        // the property is there, but requires a DLL that can't be provided. This
        // means that we need to wrap this in a try/catch so that this can
        // continue.
    
        try { 
            filter = !!(document.body.filters);
        } catch (e) {}    
    
        OpenLayers.Util.alphaHackNeeded = (filter && 
                                           (version >= 5.5) && (version < 7));
    }
    return OpenLayers.Util.alphaHackNeeded;
};

/** 
 * Function: modifyAlphaImageDiv
 * 
 * Parameters:
 * div - {DOMElement} Div containing Alpha-adjusted Image
 * id - {String}
 * px - {<OpenLayers.Pixel>}
 * sz - {<OpenLayers.Size>}
 * imgURL - {String}
 * position - {String}
 * border - {String}
 * sizing - {String} 'crop', 'scale', or 'image'. Default is "scale"
 * opacity - {Float} Fractional value (0.0 - 1.0)
 */ 
OpenLayers.Util.modifyAlphaImageDiv = function(div, id, px, sz, imgURL, 
                                               position, border, sizing, 
                                               opacity) {

    OpenLayers.Util.modifyDOMElement(div, id, px, sz, position,
                                     null, null, opacity);

    var img = div.childNodes[0];

    if (imgURL) {
        img.src = imgURL;
    }
    OpenLayers.Util.modifyDOMElement(img, div.id + "_innerImage", null, sz, 
                                     "relative", border);
    
    if (OpenLayers.Util.alphaHack()) {
        if(div.style.display != "none") {
            div.style.display = "inline-block";
        }
        if (sizing == null) {
            sizing = "scale";
        }
        
        div.style.filter = "progid:DXImageTransform.Microsoft" +
                           ".AlphaImageLoader(src='" + img.src + "', " +
                           "sizingMethod='" + sizing + "')";
        if (parseFloat(div.style.opacity) >= 0.0 && 
            parseFloat(div.style.opacity) < 1.0) {
            div.style.filter += " alpha(opacity=" + div.style.opacity * 100 + ")";
        }

        img.style.filter = "alpha(opacity=0)";
    }
};

/** 
 * Function: createAlphaImageDiv
 * 
 * Parameters:
 * id - {String}
 * px - {<OpenLayers.Pixel>}
 * sz - {<OpenLayers.Size>}
 * imgURL - {String}
 * position - {String}
 * border - {String}
 * sizing - {String} 'crop', 'scale', or 'image'. Default is "scale"
 * opacity - {Float} Fractional value (0.0 - 1.0)
 * delayDisplay - {Boolean} If true waits until the image has been
 *                          loaded.
 * 
 * Returns:
 * {DOMElement} A DOM Div created with a DOM Image inside it. If the hack is 
 *              needed for transparency in IE, it is added.
 */ 
OpenLayers.Util.createAlphaImageDiv = function(id, px, sz, imgURL, 
                                               position, border, sizing, 
                                               opacity, delayDisplay) {
    
    var div = OpenLayers.Util.createDiv();
    var img = OpenLayers.Util.createImage(null, null, null, null, null, null, 
                                          null, delayDisplay);
    div.appendChild(img);

    OpenLayers.Util.modifyAlphaImageDiv(div, id, px, sz, imgURL, position, 
                                        border, sizing, opacity);
    
    return div;
};


/** 
 * Function: upperCaseObject
 * Creates a new hashtable and copies over all the keys from the 
 *     passed-in object, but storing them under an uppercased
 *     version of the key at which they were stored.
 * 
 * Parameters: 
 * object - {Object}
 * 
 * Returns: 
 * {Object} A new Object with all the same keys but uppercased
 */
OpenLayers.Util.upperCaseObject = function (object) {
    var uObject = {};
    for (var key in object) {
        uObject[key.toUpperCase()] = object[key];
    }
    return uObject;
};

/** 
 * Function: applyDefaults
 * Takes an object and copies any properties that don't exist from
 *     another properties, by analogy with OpenLayers.Util.extend() from
 *     Prototype.js.
 * 
 * Parameters:
 * to - {Object} The destination object.
 * from - {Object} The source object.  Any properties of this object that
 *     are undefined in the to object will be set on the to object.
 *
 * Returns:
 * {Object} A reference to the to object.  Note that the to argument is modified
 *     in place and returned by this function.
 */
OpenLayers.Util.applyDefaults = function (to, from) {
    to = to || {};
    /*
     * FF/Windows < 2.0.0.13 reports "Illegal operation on WrappedNative
     * prototype object" when calling hawOwnProperty if the source object is an
     * instance of window.Event.
     */
    var fromIsEvt = typeof window.Event == "function"
                    && from instanceof window.Event;

    for (var key in from) {
        if (to[key] === undefined ||
            (!fromIsEvt && from.hasOwnProperty
             && from.hasOwnProperty(key) && !to.hasOwnProperty(key))) {
            to[key] = from[key];
        }
    }
    /**
     * IE doesn't include the toString property when iterating over an object's
     * properties with the for(property in object) syntax.  Explicitly check if
     * the source has its own toString property.
     */
    if(!fromIsEvt && from && from.hasOwnProperty
       && from.hasOwnProperty('toString') && !to.hasOwnProperty('toString')) {
        to.toString = from.toString;
    }
    
    return to;
};

/**
 * Function: getParameterString
 * 
 * Parameters:
 * params - {Object}
 * 
 * Returns:
 * {String} A concatenation of the properties of an object in 
 *          http parameter notation. 
 *          (ex. <i>"key1=value1&key2=value2&key3=value3"</i>)
 *          If a parameter is actually a list, that parameter will then
 *          be set to a comma-seperated list of values (foo,bar) instead
 *          of being URL escaped (foo%3Abar). 
 */
OpenLayers.Util.getParameterString = function(params) {
    var paramsArray = [];
    
    for (var key in params) {
      var value = params[key];
      if ((value != null) && (typeof value != 'function')) {
        var encodedValue;
        if (typeof value == 'object' && value.constructor == Array) {
          /* value is an array; encode items and separate with "," */
          var encodedItemArray = [];
          var item;
          for (var itemIndex=0, len=value.length; itemIndex<len; itemIndex++) {
            item = value[itemIndex];
            encodedItemArray.push(encodeURIComponent(
                (item === null || item === undefined) ? "" : item)
            );
          }
          encodedValue = encodedItemArray.join(",");
        }
        else {
          /* value is a string; simply encode */
          encodedValue = encodeURIComponent(value);
        }
        paramsArray.push(encodeURIComponent(key) + "=" + encodedValue);
      }
    }
    
    return paramsArray.join("&");
};

/**
 * Function: urlAppend
 * Appends a parameter string to a url. This function includes the logic for
 * using the appropriate character (none, & or ?) to append to the url before
 * appending the param string.
 * 
 * Parameters:
 * url - {String} The url to append to
 * paramStr - {String} The param string to append
 * 
 * Returns:
 * {String} The new url
 */
OpenLayers.Util.urlAppend = function(url, paramStr) {
    var newUrl = url;
    if(paramStr) {
        var parts = (url + " ").split(/[?&]/);
        newUrl += (parts.pop() === " " ?
            paramStr :
            parts.length ? "&" + paramStr : "?" + paramStr);
    }
    return newUrl;
};

/**
 * Property: ImgPath
 * {String} Default is ''.
 */
OpenLayers.ImgPath = '';

/** 
 * Function: getImagesLocation
 * 
 * Returns:
 * {String} The fully formatted image location string
 */
OpenLayers.Util.getImagesLocation = function() {
    return OpenLayers.ImgPath || (OpenLayers._getScriptLocation() + "img/");
};


/** 
 * Function: Try
 * Execute functions until one of them doesn't throw an error. 
 *     Capitalized because "try" is a reserved word in JavaScript.
 *     Taken directly from OpenLayers.Util.Try()
 * 
 * Parameters:
 * [*] - {Function} Any number of parameters may be passed to Try()
 *    It will attempt to execute each of them until one of them 
 *    successfully executes. 
 *    If none executes successfully, returns null.
 * 
 * Returns:
 * {*} The value returned by the first successfully executed function.
 */
OpenLayers.Util.Try = function() {
    var returnValue = null;

    for (var i=0, len=arguments.length; i<len; i++) {
      var lambda = arguments[i];
      try {
        returnValue = lambda();
        break;
      } catch (e) {}
    }

    return returnValue;
};

/**
 * Function: getXmlNodeValue
 * 
 * Parameters:
 * node - {XMLNode}
 * 
 * Returns:
 * {String} The text value of the given node, without breaking in firefox or IE
 */
OpenLayers.Util.getXmlNodeValue = function(node) {
    var val = null;
    OpenLayers.Util.Try( 
        function() {
            val = node.text;
            if (!val) {
                val = node.textContent;
            }
            if (!val) {
                val = node.firstChild.nodeValue;
            }
        }, 
        function() {
            val = node.textContent;
        }); 
    return val;
};

/** 
 * Function: mouseLeft
 * 
 * Parameters:
 * evt - {Event}
 * div - {HTMLDivElement}
 * 
 * Returns:
 * {Boolean}
 */
OpenLayers.Util.mouseLeft = function (evt, div) {
    // start with the element to which the mouse has moved
    var target = (evt.relatedTarget) ? evt.relatedTarget : evt.toElement;
    // walk up the DOM tree.
    while (target != div && target != null) {
        target = target.parentNode;
    }
    // if the target we stop at isn't the div, then we've left the div.
    return (target != div);
};

/**
 * Property: precision
 * {Number} The number of significant digits to retain to avoid
 * floating point precision errors.
 *
 * We use 14 as a "safe" default because, although IEEE 754 double floats
 * (standard on most modern operating systems) support up to about 16
 * significant digits, 14 significant digits are sufficient to represent
 * sub-millimeter accuracy in any coordinate system that anyone is likely to
 * use with OpenLayers.
 *
 * If DEFAULT_PRECISION is set to 0, the original non-truncating behavior
 * of OpenLayers <2.8 is preserved. Be aware that this will cause problems
 * with certain projections, e.g. spherical Mercator.
 *
 */
OpenLayers.Util.DEFAULT_PRECISION = 14;

/**
 * Function: toFloat
 * Convenience method to cast an object to a Number, rounded to the
 * desired floating point precision.
 *
 * Parameters:
 * number    - {Number} The number to cast and round.
 * precision - {Number} An integer suitable for use with
 *      Number.toPrecision(). Defaults to OpenLayers.Util.DEFAULT_PRECISION.
 *      If set to 0, no rounding is performed.
 *
 * Returns:
 * {Number} The cast, rounded number.
 */
OpenLayers.Util.toFloat = function (number, precision) {
    if (precision == null) {
        precision = OpenLayers.Util.DEFAULT_PRECISION;
    }
    if (typeof number !== "number") {
        number = parseFloat(number);
    }
    return precision === 0 ? number :
                             parseFloat(number.toPrecision(precision));
};

/**
 * Function: rad
 * 
 * Parameters:
 * x - {Float}
 * 
 * Returns:
 * {Float}
 */
OpenLayers.Util.rad = function(x) {return x*Math.PI/180;};

/**
 * Function: deg
 *
 * Parameters:
 * x - {Float}
 *
 * Returns:
 * {Float}
 */
OpenLayers.Util.deg = function(x) {return x*180/Math.PI;};

/**
 * Property: VincentyConstants
 * {Object} Constants for Vincenty functions.
 */
OpenLayers.Util.VincentyConstants = {
    a: 6378137,
    b: 6356752.3142,
    f: 1/298.257223563
};

/**
 * APIFunction: distVincenty
 * Given two objects representing points with geographic coordinates, this
 *     calculates the distance between those points on the surface of an
 *     ellipsoid.
 *
 * Parameters:
 * p1 - {<OpenLayers.LonLat>} (or any object with both .lat, .lon properties)
 * p2 - {<OpenLayers.LonLat>} (or any object with both .lat, .lon properties)
 *
 * Returns:
 * {Float} The distance (in km) between the two input points as measured on an
 *     ellipsoid.  Note that the input point objects must be in geographic
 *     coordinates (decimal degrees) and the return distance is in kilometers.
 */
OpenLayers.Util.distVincenty = function(p1, p2) {
    var ct = OpenLayers.Util.VincentyConstants;
    var a = ct.a, b = ct.b, f = ct.f;

    var L = OpenLayers.Util.rad(p2.lon - p1.lon);
    var U1 = Math.atan((1-f) * Math.tan(OpenLayers.Util.rad(p1.lat)));
    var U2 = Math.atan((1-f) * Math.tan(OpenLayers.Util.rad(p2.lat)));
    var sinU1 = Math.sin(U1), cosU1 = Math.cos(U1);
    var sinU2 = Math.sin(U2), cosU2 = Math.cos(U2);
    var lambda = L, lambdaP = 2*Math.PI;
    var iterLimit = 20;
    while (Math.abs(lambda-lambdaP) > 1e-12 && --iterLimit>0) {
        var sinLambda = Math.sin(lambda), cosLambda = Math.cos(lambda);
        var sinSigma = Math.sqrt((cosU2*sinLambda) * (cosU2*sinLambda) +
        (cosU1*sinU2-sinU1*cosU2*cosLambda) * (cosU1*sinU2-sinU1*cosU2*cosLambda));
        if (sinSigma==0) {
            return 0;  // co-incident points
        }
        var cosSigma = sinU1*sinU2 + cosU1*cosU2*cosLambda;
        var sigma = Math.atan2(sinSigma, cosSigma);
        var alpha = Math.asin(cosU1 * cosU2 * sinLambda / sinSigma);
        var cosSqAlpha = Math.cos(alpha) * Math.cos(alpha);
        var cos2SigmaM = cosSigma - 2*sinU1*sinU2/cosSqAlpha;
        var C = f/16*cosSqAlpha*(4+f*(4-3*cosSqAlpha));
        lambdaP = lambda;
        lambda = L + (1-C) * f * Math.sin(alpha) *
        (sigma + C*sinSigma*(cos2SigmaM+C*cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)));
    }
    if (iterLimit==0) {
        return NaN;  // formula failed to converge
    }
    var uSq = cosSqAlpha * (a*a - b*b) / (b*b);
    var A = 1 + uSq/16384*(4096+uSq*(-768+uSq*(320-175*uSq)));
    var B = uSq/1024 * (256+uSq*(-128+uSq*(74-47*uSq)));
    var deltaSigma = B*sinSigma*(cos2SigmaM+B/4*(cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)-
        B/6*cos2SigmaM*(-3+4*sinSigma*sinSigma)*(-3+4*cos2SigmaM*cos2SigmaM)));
    var s = b*A*(sigma-deltaSigma);
    var d = s.toFixed(3)/1000; // round to 1mm precision
    return d;
};

/**
 * APIFunction: destinationVincenty
 * Calculate destination point given start point lat/long (numeric degrees),
 * bearing (numeric degrees) & distance (in m).
 * Adapted from Chris Veness work, see
 * http://www.movable-type.co.uk/scripts/latlong-vincenty-direct.html
 *
 * Parameters:
 * lonlat  - {<OpenLayers.LonLat>} (or any object with both .lat, .lon
 *     properties) The start point.
 * brng     - {Float} The bearing (degrees).
 * dist     - {Float} The ground distance (meters).
 *
 * Returns:
 * {<OpenLayers.LonLat>} The destination point.
 */
OpenLayers.Util.destinationVincenty = function(lonlat, brng, dist) {
    var u = OpenLayers.Util;
    var ct = u.VincentyConstants;
    var a = ct.a, b = ct.b, f = ct.f;

    var lon1 = lonlat.lon;
    var lat1 = lonlat.lat;

    var s = dist;
    var alpha1 = u.rad(brng);
    var sinAlpha1 = Math.sin(alpha1);
    var cosAlpha1 = Math.cos(alpha1);

    var tanU1 = (1-f) * Math.tan(u.rad(lat1));
    var cosU1 = 1 / Math.sqrt((1 + tanU1*tanU1)), sinU1 = tanU1*cosU1;
    var sigma1 = Math.atan2(tanU1, cosAlpha1);
    var sinAlpha = cosU1 * sinAlpha1;
    var cosSqAlpha = 1 - sinAlpha*sinAlpha;
    var uSq = cosSqAlpha * (a*a - b*b) / (b*b);
    var A = 1 + uSq/16384*(4096+uSq*(-768+uSq*(320-175*uSq)));
    var B = uSq/1024 * (256+uSq*(-128+uSq*(74-47*uSq)));

    var sigma = s / (b*A), sigmaP = 2*Math.PI;
    while (Math.abs(sigma-sigmaP) > 1e-12) {
        var cos2SigmaM = Math.cos(2*sigma1 + sigma);
        var sinSigma = Math.sin(sigma);
        var cosSigma = Math.cos(sigma);
        var deltaSigma = B*sinSigma*(cos2SigmaM+B/4*(cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)-
            B/6*cos2SigmaM*(-3+4*sinSigma*sinSigma)*(-3+4*cos2SigmaM*cos2SigmaM)));
        sigmaP = sigma;
        sigma = s / (b*A) + deltaSigma;
    }

    var tmp = sinU1*sinSigma - cosU1*cosSigma*cosAlpha1;
    var lat2 = Math.atan2(sinU1*cosSigma + cosU1*sinSigma*cosAlpha1,
        (1-f)*Math.sqrt(sinAlpha*sinAlpha + tmp*tmp));
    var lambda = Math.atan2(sinSigma*sinAlpha1, cosU1*cosSigma - sinU1*sinSigma*cosAlpha1);
    var C = f/16*cosSqAlpha*(4+f*(4-3*cosSqAlpha));
    var L = lambda - (1-C) * f * sinAlpha *
        (sigma + C*sinSigma*(cos2SigmaM+C*cosSigma*(-1+2*cos2SigmaM*cos2SigmaM)));

    var revAz = Math.atan2(sinAlpha, -tmp);  // final bearing

    return new OpenLayers.LonLat(lon1+u.deg(L), u.deg(lat2));
};

/**
 * Function: getParameters
 * Parse the parameters from a URL or from the current page itself into a 
 *     JavaScript Object. Note that parameter values with commas are separated
 *     out into an Array.
 * 
 * Parameters:
 * url - {String} Optional url used to extract the query string.
 *                If url is null or is not supplied, query string is taken 
 *                from the page location.
 * 
 * Returns:
 * {Object} An object of key/value pairs from the query string.
 */
OpenLayers.Util.getParameters = function(url) {
    // if no url specified, take it from the location bar
    url = (url === null || url === undefined) ? window.location.href : url;

    //parse out parameters portion of url string
    var paramsString = "";
    if (OpenLayers.String.contains(url, '?')) {
        var start = url.indexOf('?') + 1;
        var end = OpenLayers.String.contains(url, "#") ?
                    url.indexOf('#') : url.length;
        paramsString = url.substring(start, end);
    }

    var parameters = {};
    var pairs = paramsString.split(/[&;]/);
    for(var i=0, len=pairs.length; i<len; ++i) {
        var keyValue = pairs[i].split('=');
        if (keyValue[0]) {

            var key = keyValue[0];
            try {
                key = decodeURIComponent(key);
            } catch (err) {
                key = unescape(key);
            }
            
            // being liberal by replacing "+" with " "
            var value = (keyValue[1] || '').replace(/\+/g, " ");

            try {
                value = decodeURIComponent(value);
            } catch (err) {
                value = unescape(value);
            }
            
            // follow OGC convention of comma delimited values
            value = value.split(",");

            //if there's only one value, do not return as array                    
            if (value.length == 1) {
                value = value[0];
            }                
            
            parameters[key] = value;
         }
     }
    return parameters;
};

/**
 * Function: getArgs
 * *Deprecated*.  Will be removed in 3.0.  Please use instead
 *     <OpenLayers.Util.getParameters>
 * 
 * Parameters:
 * url - {String} Optional url used to extract the query string.
 *                If null, query string is taken from page location.
 * 
 * Returns:
 * {Object} An object of key/value pairs from the query string.
 */
OpenLayers.Util.getArgs = function(url) {
    OpenLayers.Console.warn(
        OpenLayers.i18n(
            "methodDeprecated", {'newMethod': 'OpenLayers.Util.getParameters'}
        )
    );
    return OpenLayers.Util.getParameters(url);
};

/**
 * Property: lastSeqID
 * {Integer} The ever-incrementing count variable.
 *           Used for generating unique ids.
 */
OpenLayers.Util.lastSeqID = 0;

/**
 * Function: createUniqueID
 * Create a unique identifier for this session.  Each time this function
 *     is called, a counter is incremented.  The return will be the optional
 *     prefix (defaults to "id_") appended with the counter value.
 * 
 * Parameters:
 * prefix {String} Optionsal string to prefix unique id. Default is "id_".
 * 
 * Returns:
 * {String} A unique id string, built on the passed in prefix.
 */
OpenLayers.Util.createUniqueID = function(prefix) {
    if (prefix == null) {
        prefix = "id_";
    }
    OpenLayers.Util.lastSeqID += 1; 
    return prefix + OpenLayers.Util.lastSeqID;        
};

/**
 * Constant: INCHES_PER_UNIT
 * {Object} Constant inches per unit -- borrowed from MapServer mapscale.c
 * derivation of nautical miles from http://en.wikipedia.org/wiki/Nautical_mile
 * Includes the full set of units supported by CS-MAP (http://trac.osgeo.org/csmap/)
 * and PROJ.4 (http://trac.osgeo.org/proj/)
 * The hardcoded table is maintain in a CS-MAP source code module named CSdataU.c
 * The hardcoded table of PROJ.4 units are in pj_units.c.
 */
OpenLayers.INCHES_PER_UNIT = { 
    'inches': 1.0,
    'ft': 12.0,
    'mi': 63360.0,
    'm': 39.3701,
    'km': 39370.1,
    'dd': 4374754,
    'yd': 36
};
OpenLayers.INCHES_PER_UNIT["in"]= OpenLayers.INCHES_PER_UNIT.inches;
OpenLayers.INCHES_PER_UNIT["degrees"] = OpenLayers.INCHES_PER_UNIT.dd;
OpenLayers.INCHES_PER_UNIT["nmi"] = 1852 * OpenLayers.INCHES_PER_UNIT.m;

// Units from CS-Map
OpenLayers.METERS_PER_INCH = 0.02540005080010160020;
OpenLayers.Util.extend(OpenLayers.INCHES_PER_UNIT, {
    "Inch": OpenLayers.INCHES_PER_UNIT.inches,
    "Meter": 1.0 / OpenLayers.METERS_PER_INCH,   //EPSG:9001
    "Foot": 0.30480060960121920243 / OpenLayers.METERS_PER_INCH,   //EPSG:9003
    "IFoot": 0.30480000000000000000 / OpenLayers.METERS_PER_INCH,   //EPSG:9002
    "ClarkeFoot": 0.3047972651151 / OpenLayers.METERS_PER_INCH,   //EPSG:9005
    "SearsFoot": 0.30479947153867624624 / OpenLayers.METERS_PER_INCH,   //EPSG:9041
    "GoldCoastFoot": 0.30479971018150881758 / OpenLayers.METERS_PER_INCH,   //EPSG:9094
    "IInch": 0.02540000000000000000 / OpenLayers.METERS_PER_INCH,
    "MicroInch": 0.00002540000000000000 / OpenLayers.METERS_PER_INCH,
    "Mil": 0.00000002540000000000 / OpenLayers.METERS_PER_INCH,
    "Centimeter": 0.01000000000000000000 / OpenLayers.METERS_PER_INCH,
    "Kilometer": 1000.00000000000000000000 / OpenLayers.METERS_PER_INCH,   //EPSG:9036
    "Yard": 0.91440182880365760731 / OpenLayers.METERS_PER_INCH,
    "SearsYard": 0.914398414616029 / OpenLayers.METERS_PER_INCH,   //EPSG:9040
    "IndianYard": 0.91439853074444079983 / OpenLayers.METERS_PER_INCH,   //EPSG:9084
    "IndianYd37": 0.91439523 / OpenLayers.METERS_PER_INCH,   //EPSG:9085
    "IndianYd62": 0.9143988 / OpenLayers.METERS_PER_INCH,   //EPSG:9086
    "IndianYd75": 0.9143985 / OpenLayers.METERS_PER_INCH,   //EPSG:9087
    "IndianFoot": 0.30479951 / OpenLayers.METERS_PER_INCH,   //EPSG:9080
    "IndianFt37": 0.30479841 / OpenLayers.METERS_PER_INCH,   //EPSG:9081
    "IndianFt62": 0.3047996 / OpenLayers.METERS_PER_INCH,   //EPSG:9082
    "IndianFt75": 0.3047995 / OpenLayers.METERS_PER_INCH,   //EPSG:9083
    "Mile": 1609.34721869443738887477 / OpenLayers.METERS_PER_INCH,
    "IYard": 0.91440000000000000000 / OpenLayers.METERS_PER_INCH,   //EPSG:9096
    "IMile": 1609.34400000000000000000 / OpenLayers.METERS_PER_INCH,   //EPSG:9093
    "NautM": 1852.00000000000000000000 / OpenLayers.METERS_PER_INCH,   //EPSG:9030
    "Lat-66": 110943.316488932731 / OpenLayers.METERS_PER_INCH,
    "Lat-83": 110946.25736872234125 / OpenLayers.METERS_PER_INCH,
    "Decimeter": 0.10000000000000000000 / OpenLayers.METERS_PER_INCH,
    "Millimeter": 0.00100000000000000000 / OpenLayers.METERS_PER_INCH,
    "Dekameter": 10.00000000000000000000 / OpenLayers.METERS_PER_INCH,
    "Decameter": 10.00000000000000000000 / OpenLayers.METERS_PER_INCH,
    "Hectometer": 100.00000000000000000000 / OpenLayers.METERS_PER_INCH,
    "GermanMeter": 1.0000135965 / OpenLayers.METERS_PER_INCH,   //EPSG:9031
    "CaGrid": 0.999738 / OpenLayers.METERS_PER_INCH,
    "ClarkeChain": 20.1166194976 / OpenLayers.METERS_PER_INCH,   //EPSG:9038
    "GunterChain": 20.11684023368047 / OpenLayers.METERS_PER_INCH,   //EPSG:9033
    "BenoitChain": 20.116782494375872 / OpenLayers.METERS_PER_INCH,   //EPSG:9062
    "SearsChain": 20.11676512155 / OpenLayers.METERS_PER_INCH,   //EPSG:9042
    "ClarkeLink": 0.201166194976 / OpenLayers.METERS_PER_INCH,   //EPSG:9039
    "GunterLink": 0.2011684023368047 / OpenLayers.METERS_PER_INCH,   //EPSG:9034
    "BenoitLink": 0.20116782494375872 / OpenLayers.METERS_PER_INCH,   //EPSG:9063
    "SearsLink": 0.2011676512155 / OpenLayers.METERS_PER_INCH,   //EPSG:9043
    "Rod": 5.02921005842012 / OpenLayers.METERS_PER_INCH,
    "IntnlChain": 20.1168 / OpenLayers.METERS_PER_INCH,   //EPSG:9097
    "IntnlLink": 0.201168 / OpenLayers.METERS_PER_INCH,   //EPSG:9098
    "Perch": 5.02921005842012 / OpenLayers.METERS_PER_INCH,
    "Pole": 5.02921005842012 / OpenLayers.METERS_PER_INCH,
    "Furlong": 201.1684023368046 / OpenLayers.METERS_PER_INCH,
    "Rood": 3.778266898 / OpenLayers.METERS_PER_INCH,
    "CapeFoot": 0.3047972615 / OpenLayers.METERS_PER_INCH,
    "Brealey": 375.00000000000000000000 / OpenLayers.METERS_PER_INCH,
    "ModAmFt": 0.304812252984505969011938 / OpenLayers.METERS_PER_INCH,
    "Fathom": 1.8288 / OpenLayers.METERS_PER_INCH,
    "NautM-UK": 1853.184 / OpenLayers.METERS_PER_INCH,
    "50kilometers": 50000.0 / OpenLayers.METERS_PER_INCH,
    "150kilometers": 150000.0 / OpenLayers.METERS_PER_INCH
});

//unit abbreviations supported by PROJ.4
OpenLayers.Util.extend(OpenLayers.INCHES_PER_UNIT, {
    "mm": OpenLayers.INCHES_PER_UNIT["Meter"] / 1000.0,
    "cm": OpenLayers.INCHES_PER_UNIT["Meter"] / 100.0,
    "dm": OpenLayers.INCHES_PER_UNIT["Meter"] * 100.0,
    "km": OpenLayers.INCHES_PER_UNIT["Meter"] * 1000.0,
    "kmi": OpenLayers.INCHES_PER_UNIT["nmi"],    //International Nautical Mile
    "fath": OpenLayers.INCHES_PER_UNIT["Fathom"], //International Fathom
    "ch": OpenLayers.INCHES_PER_UNIT["IntnlChain"],  //International Chain
    "link": OpenLayers.INCHES_PER_UNIT["IntnlLink"], //International Link
    "us-in": OpenLayers.INCHES_PER_UNIT["inches"], //U.S. Surveyor's Inch
    "us-ft": OpenLayers.INCHES_PER_UNIT["Foot"],    //U.S. Surveyor's Foot
    "us-yd": OpenLayers.INCHES_PER_UNIT["Yard"],    //U.S. Surveyor's Yard
    "us-ch": OpenLayers.INCHES_PER_UNIT["GunterChain"], //U.S. Surveyor's Chain
    "us-mi": OpenLayers.INCHES_PER_UNIT["Mile"],   //U.S. Surveyor's Statute Mile
    "ind-yd": OpenLayers.INCHES_PER_UNIT["IndianYd37"],  //Indian Yard
    "ind-ft": OpenLayers.INCHES_PER_UNIT["IndianFt37"],  //Indian Foot
    "ind-ch": 20.11669506 / OpenLayers.METERS_PER_INCH  //Indian Chain
});

/** 
 * Constant: DOTS_PER_INCH
 * {Integer} 72 (A sensible default)
 */
OpenLayers.DOTS_PER_INCH = 72;

/**
 * Function: normalizeScale
 * 
 * Parameters:
 * scale - {float}
 * 
 * Returns:
 * {Float} A normalized scale value, in 1 / X format. 
 *         This means that if a value less than one ( already 1/x) is passed
 *         in, it just returns scale directly. Otherwise, it returns 
 *         1 / scale
 */
OpenLayers.Util.normalizeScale = function (scale) {
    var normScale = (scale > 1.0) ? (1.0 / scale) 
                                  : scale;
    return normScale;
};

/**
 * Function: getResolutionFromScale
 * 
 * Parameters:
 * scale - {Float}
 * units - {String} Index into OpenLayers.INCHES_PER_UNIT hashtable.
 *                  Default is degrees
 * 
 * Returns:
 * {Float} The corresponding resolution given passed-in scale and unit 
 *     parameters.  If the given scale is falsey, the returned resolution will
 *     be undefined.
 */
OpenLayers.Util.getResolutionFromScale = function (scale, units) {
    var resolution;
    if (scale) {
        if (units == null) {
            units = "degrees";
        }
        var normScale = OpenLayers.Util.normalizeScale(scale);
        resolution = 1 / (normScale * OpenLayers.INCHES_PER_UNIT[units]
                                        * OpenLayers.DOTS_PER_INCH);        
    }
    return resolution;
};

/**
 * Function: getScaleFromResolution
 * 
 * Parameters:
 * resolution - {Float}
 * units - {String} Index into OpenLayers.INCHES_PER_UNIT hashtable.
 *                  Default is degrees
 * 
 * Returns:
 * {Float} The corresponding scale given passed-in resolution and unit 
 *         parameters.
 */
OpenLayers.Util.getScaleFromResolution = function (resolution, units) {

    if (units == null) {
        units = "degrees";
    }

    var scale = resolution * OpenLayers.INCHES_PER_UNIT[units] *
                    OpenLayers.DOTS_PER_INCH;
    return scale;
};

/**
 * Function: safeStopPropagation
 * *Deprecated*. This function has been deprecated. Please use directly 
 *     <OpenLayers.Event.stop> passing 'true' as the 2nd 
 *     argument (preventDefault)
 * 
 * Safely stop the propagation of an event *without* preventing
 *   the default browser action from occurring.
 * 
 * Parameter:
 * evt - {Event}
 */
OpenLayers.Util.safeStopPropagation = function(evt) {
    OpenLayers.Event.stop(evt, true);
};

/**
 * Function: pagePosition
 * Calculates the position of an element on the page (see
 * http://code.google.com/p/doctype/wiki/ArticlePageOffset)
 *
 * OpenLayers.Util.pagePosition is based on Yahoo's getXY method, which is
 * Copyright (c) 2006, Yahoo! Inc.
 * All rights reserved.
 * 
 * Redistribution and use of this software in source and binary forms, with or
 * without modification, are permitted provided that the following conditions
 * are met:
 * 
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * 
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * 
 * * Neither the name of Yahoo! Inc. nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without
 *   specific prior written permission of Yahoo! Inc.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Parameters:
 * forElement - {DOMElement}
 * 
 * Returns:
 * {Array} two item array, Left value then Top value.
 */
OpenLayers.Util.pagePosition =  function(forElement) {
    // NOTE: If element is hidden (display none or disconnected or any the
    // ancestors are hidden) we get (0,0) by default but we still do the
    // accumulation of scroll position.

    var pos = [0, 0];
    var viewportElement = OpenLayers.Util.getViewportElement();
    if (!forElement || forElement == window || forElement == viewportElement) {
        // viewport is always at 0,0 as that defined the coordinate system for
        // this function - this avoids special case checks in the code below
        return pos;
    }

    // Gecko browsers normally use getBoxObjectFor to calculate the position.
    // When invoked for an element with an implicit absolute position though it
    // can be off by one. Therefore the recursive implementation is used in
    // those (relatively rare) cases.
    var BUGGY_GECKO_BOX_OBJECT =
        OpenLayers.IS_GECKO && document.getBoxObjectFor &&
        OpenLayers.Element.getStyle(forElement, 'position') == 'absolute' &&
        (forElement.style.top == '' || forElement.style.left == '');

    var parent = null;
    var box;

    if (forElement.getBoundingClientRect) { // IE
        box = forElement.getBoundingClientRect();
        var scrollTop = viewportElement.scrollTop;
        var scrollLeft = viewportElement.scrollLeft;

        pos[0] = box.left + scrollLeft;
        pos[1] = box.top + scrollTop;

    } else if (document.getBoxObjectFor && !BUGGY_GECKO_BOX_OBJECT) { // gecko
        // Gecko ignores the scroll values for ancestors, up to 1.9.  See:
        // https://bugzilla.mozilla.org/show_bug.cgi?id=328881 and
        // https://bugzilla.mozilla.org/show_bug.cgi?id=330619

        box = document.getBoxObjectFor(forElement);
        var vpBox = document.getBoxObjectFor(viewportElement);
        pos[0] = box.screenX - vpBox.screenX;
        pos[1] = box.screenY - vpBox.screenY;

    } else { // safari/opera
        pos[0] = forElement.offsetLeft;
        pos[1] = forElement.offsetTop;
        parent = forElement.offsetParent;
        if (parent != forElement) {
            while (parent) {
                pos[0] += parent.offsetLeft;
                pos[1] += parent.offsetTop;
                parent = parent.offsetParent;
            }
        }

        var browser = OpenLayers.BROWSER_NAME;

        // opera & (safari absolute) incorrectly account for body offsetTop
        if (browser == "opera" || (browser == "safari" &&
              OpenLayers.Element.getStyle(forElement, 'position') == 'absolute')) {
            pos[1] -= document.body.offsetTop;
        }

        // accumulate the scroll positions for everything but the body element
        parent = forElement.offsetParent;
        while (parent && parent != document.body) {
            pos[0] -= parent.scrollLeft;
            // see https://bugs.opera.com/show_bug.cgi?id=249965
            if (browser != "opera" || parent.tagName != 'TR') {
                pos[1] -= parent.scrollTop;
            }
            parent = parent.offsetParent;
        }
    }
    
    return pos;
};

/**
 * Function: getViewportElement
 * Returns die viewport element of the document. The viewport element is
 * usually document.documentElement, except in IE,where it is either
 * document.body or document.documentElement, depending on the document's
 * compatibility mode (see
 * http://code.google.com/p/doctype/wiki/ArticleClientViewportElement)
 */
OpenLayers.Util.getViewportElement = function() {
    var viewportElement = arguments.callee.viewportElement;
    if (viewportElement == undefined) {
        viewportElement = (OpenLayers.BROWSER_NAME == "msie" &&
            document.compatMode != 'CSS1Compat') ? document.body :
            document.documentElement;
        arguments.callee.viewportElement = viewportElement;
    }
    return viewportElement;
};

/** 
 * Function: isEquivalentUrl
 * Test two URLs for equivalence. 
 * 
 * Setting 'ignoreCase' allows for case-independent comparison.
 * 
 * Comparison is based on: 
 *  - Protocol
 *  - Host (evaluated without the port)
 *  - Port (set 'ignorePort80' to ignore "80" values)
 *  - Hash ( set 'ignoreHash' to disable)
 *  - Pathname (for relative <-> absolute comparison) 
 *  - Arguments (so they can be out of order)
 *  
 * Parameters:
 * url1 - {String}
 * url2 - {String}
 * options - {Object} Allows for customization of comparison:
 *                    'ignoreCase' - Default is True
 *                    'ignorePort80' - Default is True
 *                    'ignoreHash' - Default is True
 *
 * Returns:
 * {Boolean} Whether or not the two URLs are equivalent
 */
OpenLayers.Util.isEquivalentUrl = function(url1, url2, options) {
    options = options || {};

    OpenLayers.Util.applyDefaults(options, {
        ignoreCase: true,
        ignorePort80: true,
        ignoreHash: true
    });

    var urlObj1 = OpenLayers.Util.createUrlObject(url1, options);
    var urlObj2 = OpenLayers.Util.createUrlObject(url2, options);

    //compare all keys except for "args" (treated below)
    for(var key in urlObj1) {
        if(key !== "args") {
            if(urlObj1[key] != urlObj2[key]) {
                return false;
            }
        }
    }

    // compare search args - irrespective of order
    for(var key in urlObj1.args) {
        if(urlObj1.args[key] != urlObj2.args[key]) {
            return false;
        }
        delete urlObj2.args[key];
    }
    // urlObj2 shouldn't have any args left
    for(var key in urlObj2.args) {
        return false;
    }
    
    return true;
};

/**
 * Function: createUrlObject
 * 
 * Parameters:
 * url - {String}
 * options - {Object} A hash of options.  Can be one of:
 *            ignoreCase: lowercase url,
 *            ignorePort80: don't include explicit port if port is 80,
 *            ignoreHash: Don't include part of url after the hash (#).
 * 
 * Returns:
 * {Object} An object with separate url, a, port, host, and args parsed out 
 *          and ready for comparison
 */
OpenLayers.Util.createUrlObject = function(url, options) {
    options = options || {};

    // deal with relative urls first
    if(!(/^\w+:\/\//).test(url)) {
        var loc = window.location;
        var port = loc.port ? ":" + loc.port : "";
        var fullUrl = loc.protocol + "//" + loc.host.split(":").shift() + port;
        if(url.indexOf("/") === 0) {
            // full pathname
            url = fullUrl + url;
        } else {
            // relative to current path
            var parts = loc.pathname.split("/");
            parts.pop();
            url = fullUrl + parts.join("/") + "/" + url;
        }
    }
  
    if (options.ignoreCase) {
        url = url.toLowerCase(); 
    }

    var a = document.createElement('a');
    a.href = url;
    
    var urlObject = {};
    
    //host (without port)
    urlObject.host = a.host.split(":").shift();

    //protocol
    urlObject.protocol = a.protocol;  

    //port (get uniform browser behavior with port 80 here)
    if(options.ignorePort80) {
        urlObject.port = (a.port == "80" || a.port == "0") ? "" : a.port;
    } else {
        urlObject.port = (a.port == "" || a.port == "0") ? "80" : a.port;
    }

    //hash
    urlObject.hash = (options.ignoreHash || a.hash === "#") ? "" : a.hash;  
    
    //args
    var queryString = a.search;
    if (!queryString) {
        var qMark = url.indexOf("?");
        queryString = (qMark != -1) ? url.substr(qMark) : "";
    }
    urlObject.args = OpenLayers.Util.getParameters(queryString);

    // pathname
    //
    // This is a workaround for Internet Explorer where
    // window.location.pathname has a leading "/", but
    // a.pathname has no leading "/".
    urlObject.pathname = (a.pathname.charAt(0) == "/") ? a.pathname : "/" + a.pathname;
    
    return urlObject; 
};
 
/**
 * Function: removeTail
 * Takes a url and removes everything after the ? and #
 * 
 * Parameters:
 * url - {String} The url to process
 * 
 * Returns:
 * {String} The string with all queryString and Hash removed
 */
OpenLayers.Util.removeTail = function(url) {
    var head = null;
    
    var qMark = url.indexOf("?");
    var hashMark = url.indexOf("#");

    if (qMark == -1) {
        head = (hashMark != -1) ? url.substr(0,hashMark) : url;
    } else {
        head = (hashMark != -1) ? url.substr(0,Math.min(qMark, hashMark)) 
                                  : url.substr(0, qMark);
    }
    return head;
};

/**
 * Constant: IS_GECKO
 * {Boolean} True if the userAgent reports the browser to use the Gecko engine
 */
OpenLayers.IS_GECKO = (function() {
    var ua = navigator.userAgent.toLowerCase();
    return ua.indexOf("webkit") == -1 && ua.indexOf("gecko") != -1;
})();

/**
 * Constant: BROWSER_NAME
 * {String}
 * A substring of the navigator.userAgent property.  Depending on the userAgent
 *     property, this will be the empty string or one of the following:
 *     * "opera" -- Opera
 *     * "msie"  -- Internet Explorer
 *     * "safari" -- Safari
 *     * "firefox" -- Firefox
 *     * "mozilla" -- Mozilla
 */
OpenLayers.BROWSER_NAME = (function() {
    var name = "";
    var ua = navigator.userAgent.toLowerCase();
    if (ua.indexOf("opera") != -1) {
        name = "opera";
    } else if (ua.indexOf("msie") != -1) {
        name = "msie";
    } else if (ua.indexOf("safari") != -1) {
        name = "safari";
    } else if (ua.indexOf("mozilla") != -1) {
        if (ua.indexOf("firefox") != -1) {
            name = "firefox";
        } else {
            name = "mozilla";
        }
    }
    return name;
})();

/**
 * Function: getBrowserName
 * 
 * Returns:
 * {String} A string which specifies which is the current 
 *          browser in which we are running. 
 * 
 *          Currently-supported browser detection and codes:
 *           * 'opera' -- Opera
 *           * 'msie'  -- Internet Explorer
 *           * 'safari' -- Safari
 *           * 'firefox' -- Firefox
 *           * 'mozilla' -- Mozilla
 * 
 *          If we are unable to property identify the browser, we 
 *           return an empty string.
 */
OpenLayers.Util.getBrowserName = function() {
    return OpenLayers.BROWSER_NAME;
};

/**
 * Method: getRenderedDimensions
 * Renders the contentHTML offscreen to determine actual dimensions for
 *     popup sizing. As we need layout to determine dimensions the content
 *     is rendered -9999px to the left and absolute to ensure the 
 *     scrollbars do not flicker
 *     
 * Parameters:
 * contentHTML
 * size - {<OpenLayers.Size>} If either the 'w' or 'h' properties is 
 *     specified, we fix that dimension of the div to be measured. This is 
 *     useful in the case where we have a limit in one dimension and must 
 *     therefore meaure the flow in the other dimension.
 * options - {Object}
 *
 * Allowed Options:
 *     displayClass - {String} Optional parameter.  A CSS class name(s) string
 *         to provide the CSS context of the rendered content.
 *     containerElement - {DOMElement} Optional parameter. Insert the HTML to 
 *         this node instead of the body root when calculating dimensions. 
 * 
 * Returns:
 * {OpenLayers.Size}
 */
OpenLayers.Util.getRenderedDimensions = function(contentHTML, size, options) {
    
    var w, h;
    
    // create temp container div with restricted size
    var container = document.createElement("div");
    container.style.visibility = "hidden";
        
    var containerElement = (options && options.containerElement) 
        ? options.containerElement : document.body;

    //fix a dimension, if specified.
    if (size) {
        if (size.w) {
            w = size.w;
            container.style.width = w + "px";
        } else if (size.h) {
            h = size.h;
            container.style.height = h + "px";
        }
    }

    //add css classes, if specified
    if (options && options.displayClass) {
        container.className = options.displayClass;
    }
    
    // create temp content div and assign content
    var content = document.createElement("div");
    content.innerHTML = contentHTML;
    
    // we need overflow visible when calculating the size
    content.style.overflow = "visible";
    if (content.childNodes) {
        for (var i=0, l=content.childNodes.length; i<l; i++) {
            if (!content.childNodes[i].style) continue;
            content.childNodes[i].style.overflow = "visible";
        }
    }
    
    // add content to restricted container 
    container.appendChild(content);
    
    // append container to body for rendering
    containerElement.appendChild(container);
    
    // Opera and IE7 can't handle a node with position:aboslute if it inherits
    // position:absolute from a parent.
    var parentHasPositionAbsolute = false;
    var parent = container.parentNode;
    while (parent && parent.tagName.toLowerCase()!="body") {
        var parentPosition = OpenLayers.Element.getStyle(parent, "position");
        if(parentPosition == "absolute") {
            parentHasPositionAbsolute = true;
            break;
        } else if (parentPosition && parentPosition != "static") {
            break;
        }
        parent = parent.parentNode;
    }

    if(!parentHasPositionAbsolute) {
        container.style.position = "absolute";
    }
    
    // calculate scroll width of content and add corners and shadow width
    if (!w) {
        w = parseInt(content.scrollWidth);
    
        // update container width to allow height to adjust
        container.style.width = w + "px";
    }        
    // capture height and add shadow and corner image widths
    if (!h) {
        h = parseInt(content.scrollHeight);
    }

    // remove elements
    container.removeChild(content);
    containerElement.removeChild(container);
    
    return new OpenLayers.Size(w, h);
};

/**
 * APIFunction: getScrollbarWidth
 * This function has been modified by the OpenLayers from the original version,
 *     written by Matthew Eernisse and released under the Apache 2 
 *     license here:
 * 
 *     http://www.fleegix.org/articles/2006/05/30/getting-the-scrollbar-width-in-pixels
 * 
 *     It has been modified simply to cache its value, since it is physically 
 *     impossible that this code could ever run in more than one browser at 
 *     once. 
 * 
 * Returns:
 * {Integer}
 */
OpenLayers.Util.getScrollbarWidth = function() {
    
    var scrollbarWidth = OpenLayers.Util._scrollbarWidth;
    
    if (scrollbarWidth == null) {
        var scr = null;
        var inn = null;
        var wNoScroll = 0;
        var wScroll = 0;
    
        // Outer scrolling div
        scr = document.createElement('div');
        scr.style.position = 'absolute';
        scr.style.top = '-1000px';
        scr.style.left = '-1000px';
        scr.style.width = '100px';
        scr.style.height = '50px';
        // Start with no scrollbar
        scr.style.overflow = 'hidden';
    
        // Inner content div
        inn = document.createElement('div');
        inn.style.width = '100%';
        inn.style.height = '200px';
    
        // Put the inner div in the scrolling div
        scr.appendChild(inn);
        // Append the scrolling div to the doc
        document.body.appendChild(scr);
    
        // Width of the inner div sans scrollbar
        wNoScroll = inn.offsetWidth;
    
        // Add the scrollbar
        scr.style.overflow = 'scroll';
        // Width of the inner div width scrollbar
        wScroll = inn.offsetWidth;
    
        // Remove the scrolling div from the doc
        document.body.removeChild(document.body.lastChild);
    
        // Pixel width of the scroller
        OpenLayers.Util._scrollbarWidth = (wNoScroll - wScroll);
        scrollbarWidth = OpenLayers.Util._scrollbarWidth;
    }

    return scrollbarWidth;
};

/**
 * APIFunction: getFormattedLonLat
 * This function will return latitude or longitude value formatted as 
 *
 * Parameters:
 * coordinate - {Float} the coordinate value to be formatted
 * axis - {String} value of either 'lat' or 'lon' to indicate which axis is to
 *          to be formatted (default = lat)
 * dmsOption - {String} specify the precision of the output can be one of:
 *           'dms' show degrees minutes and seconds
 *           'dm' show only degrees and minutes
 *           'd' show only degrees
 * 
 * Returns:
 * {String} the coordinate value formatted as a string
 */
OpenLayers.Util.getFormattedLonLat = function(coordinate, axis, dmsOption) {
    if (!dmsOption) {
        dmsOption = 'dms';    //default to show degree, minutes, seconds
    }
    
    coordinate = (coordinate+540)%360 - 180; // normalize for sphere being round
    
    var abscoordinate = Math.abs(coordinate);
    var coordinatedegrees = Math.floor(abscoordinate);

    var coordinateminutes = (abscoordinate - coordinatedegrees)/(1/60);
    var tempcoordinateminutes = coordinateminutes;
    coordinateminutes = Math.floor(coordinateminutes);
    var coordinateseconds = (tempcoordinateminutes - coordinateminutes)/(1/60);
    coordinateseconds =  Math.round(coordinateseconds*10);
    coordinateseconds /= 10;

    if( coordinateseconds >= 60) { 
        coordinateseconds -= 60; 
        coordinateminutes += 1; 
        if( coordinateminutes >= 60) { 
            coordinateminutes -= 60; 
            coordinatedegrees += 1; 
        } 
    }
    
    if( coordinatedegrees < 10 ) {
        coordinatedegrees = "0" + coordinatedegrees;
    }
    var str = coordinatedegrees + "\u00B0";

    if (dmsOption.indexOf('dm') >= 0) {
        if( coordinateminutes < 10 ) {
            coordinateminutes = "0" + coordinateminutes;
        }
        str += coordinateminutes + "'";
  
        if (dmsOption.indexOf('dms') >= 0) {
            if( coordinateseconds < 10 ) {
                coordinateseconds = "0" + coordinateseconds;
            }
            str += coordinateseconds + '"';
        }
    }
    
    if (axis == "lon") {
        str += coordinate < 0 ? OpenLayers.i18n("W") : OpenLayers.i18n("E");
    } else {
        str += coordinate < 0 ? OpenLayers.i18n("S") : OpenLayers.i18n("N");
    }
    return str;
};