EDIT

function CdmOpenlayersMap(mapElement, mapserverBaseUrl, options){

	var legendImgSrc = null;

	var map = null;

	var dataBounds = null;

	var baseLayers = [];

	var defaultBaseLayer;

	var defaultControls = [ 

  	         new OpenLayers.Control.PanZoom(),

	         new OpenLayers.Control.Navigation({zoomWheelEnabled: false, handleRightClicks:true, zoomBoxKeyMask: OpenLayers.Handler.MOD_CTRL})

	       ];

	/* 

	 * EPSG:4326 and EPSG:900913 extends 

	 */

	var mapExtend_4326 = new OpenLayers.Bounds(-180, -90, 180, 90);

	var mapExtend_900913 = new OpenLayers.Bounds(-20037508.34, -20037508.34, 20037508.34, 20037508.34);

	var mapOptions={

			EPSG900913: {

				controls: defaultControls,

				maxExtent: mapExtend_900913,

				//maxResolution: (mapExtend_900913.getWidth() / options.displayWidth),

				maxResolution: (mapExtend_900913.getHeight() / (options.displayWidth / 2)),

				//maxResolution:156543.0339 * 20,

				units:'m',

				restrictedExtent: mapExtend_900913,

				projection: new OpenLayers.Projection("EPSG:900913")

			},

			EPSG4326: {

				controls: defaultControls,

				maxExtent: mapExtend_4326,

				maxResolution: (mapExtend_4326.getWidth() / options.displayWidth),

				units:'degrees',

				restrictedExtent: mapExtend_4326,

				projection: new OpenLayers.Projection("EPSG:4326")

			}

	};

	var dataProj = new OpenLayers.Projection("EPSG:4326");

	var dataLayerOptions = {

			maxExtent: mapExtend_900913,

			isBaseLayer: false,

			displayInLayerSwitcher: true

	};

	var layerByNameMap = {

			tdwg1: 'topp:tdwg_level_1',

			tdwg2: 'topp:tdwg_level_2',

			tdwg3: 'topp:tdwg_level_3',

			tdwg4: 'topp:tdwg_level_4'

	};

	/**

	 * 

	 */

	this.init = function(){

		createLayers(options.baseLayerNames, options.defaultBaseLayerName);

     //HACK !!!!!!!!!!!!!!!!!!!!!!!!!!!!

    if(defaultBaseLayer.projection == mapOptions.EPSG900913.projection){

      options.minZoom = 1;

		}

		initOpenLayers();

		// -- Distribution Layer --

		var mapServiceRequest;

		var distributionQuery = mapElement.attr('distributionQuery');

		if(distributionQuery !== undefined){

			if(typeof legendPosition == 'number'){

				distributionQuery = mergeQueryStrings(distributionQuery, 'legend=1&mlp=' + options.legendPosition);				

			}

			distributionQuery = mergeQueryStrings(distributionQuery, 'callback=?');

			var legendFormatQuery = mapElement.attr('legendFormatQuery');

			if(legendFormatQuery !== undefined){

				legendImgSrc = mergeQueryStrings('/GetLegendGraphic?SERVICE=WMS&VERSION=1.1.1', legendFormatQuery);

			}

			mapServiceRequest = mapserverBaseUrl + '/areas.php?' + distributionQuery;

			$.ajax({

				  url: mapServiceRequest,

				  dataType: "jsonp",

				  success: function(data){

						addDataLayer(data);

					}

				});

		}

		// -- Occurrence Layer --

		var occurrenceQuery = mapElement.attr('occurrenceQuery');

		if(occurrenceQuery !== undefined){

//			if(typeof legendPosition == 'number'){

//				occurrenceQuery = mergeQueryStrings(distributionQuery, 'legend=1&mlp=' + options.legendPosition);				

//			}

			occurrenceQuery = mergeQueryStrings(occurrenceQuery, 'callback=?');

//			var legendFormatQuery = mapElement.attr('legendFormatQuery');

//			if(legendFormatQuery !== undefined){

//				legendImgSrc = mergeQueryStrings('/GetLegendGraphic?SERVICE=WMS&VERSION=1.1.1', legendFormatQuery);

//			}

			mapServiceRequest = mapserverBaseUrl + '/points.php?' + occurrenceQuery;

			$.ajax({

				  url: mapServiceRequest,

				  dataType: "jsonp",

				  success: function(data){

						addDataLayer(data);

					}

				});

		}

	};

	/**

	 * Initialize the Openlayers viewer with the base layer

	 */

	var initOpenLayers = function(){

		// instatiate the openlayers viewer

		if(defaultBaseLayer.projection == mapOptions.EPSG900913.projection){

			map = new OpenLayers.Map('openlayers_map', mapOptions.EPSG900913);

		} else {

			map = new OpenLayers.Map('openlayers_map', mapOptions.EPSG4326);		

		}

		//add the base layers

		map.addLayers(baseLayers);

		map.setBaseLayer(defaultBaseLayer);

		if(options.showLayerSwitcher === true){

			map.addControl(new OpenLayers.Control.LayerSwitcher({'ascending':false}));

		}

		// zoom to the required area

		var boundsStr = (typeof options.boundingBox == 'string' && options.boundingBox.length > 6 ? options.boundingBox : '-180, -90, 180, 90');

		var zoomToBounds = OpenLayers.Bounds.fromString( boundsStr );

		map.zoomToExtent(zoomToBounds.transform(dataProj, map.getProjectionObject()), false);

		if(map.getZoom() > options.maxZoom){

			map.zoomTo(options.maxZoom);

		} else if(map.getZoom() < options.minZoom){

			map.zoomTo(options.minZoom);

		}

		// adjust height of openlayers container div

		$('#openlayers').css('height', $('#openlayers #openlayers_map').height());

	};

	/**

	 * add a distribution layer

	 */

	var addDataLayer = function(mapResponseObj){

		var layer;

		// add additional layers, get them from 

		// the mapResponseObj

		if(mapResponseObj !== undefined){

			if(mapResponseObj.points_sld !== undefined){

				// it is a response from the points.php

				//TODO points_sld should be renamed to sld in response + fill path to sld should be given				

				layer = new OpenLayers.Layer.WMS.Untiled( 

						'points', 

						"http://193.190.116.6:8080/geoserver/wms/wms",

						{layers: 'topp:rest_points' ,transparent:"true", format:"image/png"},

						dataLayerOptions );

				var sld = mapResponseObj.points_sld;

				if(sld.indexOf("http://") !== 0){

					sld = "http://edit.br.fgov.be/synthesys/www/v1/sld/" + sld;

				}

				layer.params.SLD = sld;					

				map.addLayers([layer]);

			} else {

				// it is a response from the areas.php				

				for ( var i in mapResponseObj.layers) {

				var layerData = mapResponseObj.layers[i];

					layer = new OpenLayers.Layer.WMS.Untiled( 

							layerData.tdwg, 

							mapResponseObj.geoserver + "/wms",

							{layers: layerByNameMap[layerData.tdwg] ,transparent:"true", format:"image/png"},

							dataLayerOptions );

					layer.params.SLD = layerData.sld;

					layer.setOpacity(options.distributionOpacity);

					map.addLayers([layer]);

				}

			}

			// zoom to the required area

			if(mapResponseObj.bbox !== undefined){

				var newBounds =  OpenLayers.Bounds.fromString( mapResponseObj.bbox );

				if(dataBounds !== null){

					dataBounds.extend(newBounds);

				} else if(newBounds !== undefined){

					dataBounds = newBounds;

				}

				map.zoomToExtent(dataBounds.transform(dataProj, map.getProjectionObject()), false);

				if(map.getZoom() > options.maxZoom){

					map.zoomTo(options.maxZoom);

				} else if(map.getZoom() < options.minZoom){

					map.zoomTo(options.minZoom);

				}

			}

			if(options.legendPosition !== undefined && mapResponseObj.legend !== undefined){

				var legendSrcUrl = mapResponseObj.geoserver + legendImgSrc + mapResponseObj.legend;

				addLegendAsElement(legendSrcUrl);

				//addLegendAsLayer(legendSrcUrl, map);

			}

		}

	};

	/**

	 * 

	 */

	var addLegendAsElement= function(legendSrcUrl){

		mapElement.after('<div class="openlayers_legend"><img src="' + legendSrcUrl + '"></div>');

		mapElement.next('.openlayers_legend').css('opacity', options.legendOpacity).find('img').load(function () {

			$(this).parent()

				.css('position', 'relative')

				.css('z-index', '1002')

				.css('top', -mapElement.height())

				.css('left', mapElement.width()- $(this).width())

				.width($(this).width());

		});

	};

	var addLegendAsLayer= function(legendSrcUrl, map){

		var w, h;

		// 1. download imge to find height and width

		mapElement.after('<div class="openlayers_legend"><img src="' + legendSrcUrl + '"></div>');

		mapElement.next('.openlayers_legend').css('display', 'none').css('opacity', options.legendOpacity).find('img').load(function () {

			w = mapElement.next('.openlayers_legend').find('img').width();

			h = mapElement.next('.openlayers_legend').find('img').height();

			mapElement.next('.openlayers_legend').remove();

//			createLegendLayer();

//			// 2. create the Legend Layer

			//TODO createLegendLayer as inner fiinction seems like an error

//			var createLegendLayer = function(){

//				

//				

//				var legendLayerOptions={

//						maxResolution: '.$maxRes.',

//						maxExtent: new OpenLayers.Bounds(0, 0, w, h)

//				};

//				

//				var legendLayer = new OpenLayers.Layer.Image(

//						'Legend',

//						legendSrcUrl,

//						new OpenLayers.Bounds(0, 0, w, h),

//						new OpenLayers.Size(w, h),

//						imageLayerOptions);

//			};

		});

	};

	/**

	 * merge 2 Url query strings

	 */

	 var mergeQueryStrings = function(queryStr1, queryStr2){

		if(queryStr1.charAt(queryStr1.length - 1) != '&'){

			queryStr1 += '&';

		}

		if(queryStr2.charAt(0) == '&'){

			return queryStr1 + queryStr2.substr(1);

		} else {

			return queryStr1 + queryStr2;

		}

	};

	/**

	 * 

	 */

	var createLayers = function( baseLayerNames, defaultBaseLayerName){

		//var baseLayers = new Array();

		for(var i = 0; i <  baseLayerNames.length; i++) {

			//var layerName in baseLayerNames ){

			baseLayers[i] = getLayersByName(baseLayerNames[i]);

			// set the default base layer

			if(baseLayerNames[i] == defaultBaseLayerName){

				defaultBaseLayer = baseLayers[i];

			}

		}

		//return baseLayers;

	};

	/**

	 * 

	 */

	var getLayersByName = function(layerName){

		var baseLayer;

		switch(layerName){

			case 'metacarta_vmap0':

				/**

				 * NOTE: labs.metacarta.com is currently unavailable

				 * 

				 * Available Projections:

				 * 		EPSG:900913

				 * 		EPSG:4326

				 */

				baseLayer = new OpenLayers.Layer.WMS( 

					    "Metacarta Vmap0",

					    "http://labs.metacarta.com/wms/vmap0",

					    {layers: 'basic', format:"png"},

					     {

							maxExtent: mapExtend_4326,

							isBaseLayer: true,

							displayInLayerSwitcher: true

						}

				);

			break;

			case 'osgeo_vmap0':

				/**

				 * Available Projections:

				 * 		EPSG:4326

				 */

				baseLayer = new OpenLayers.Layer.WMS(

			        "OpenLayers World",

			        "http://vmap0.tiles.osgeo.org/wms/vmap0",

			        {layers: 'basic', format:"png"},

			        {

						maxExtent: mapExtend_4326,

						isBaseLayer: true,

						displayInLayerSwitcher: true

					}

				);

			break;

			case 'edit-etopo1':

				baseLayer = new OpenLayers.Layer.WMS(

			        "ETOPO1 Global Relief Model",

			        "http://edit.br.fgov.be:8080/geoserver/wms",

			        {layers: 'topp:color_etopo1_ice_full', format:"image/png"},

			        {

						maxExtent: mapExtend_900913,

						isBaseLayer: true,

						displayInLayerSwitcher: true

					}

				);

			break;

			case 'edit-vmap0_world_basic':

				baseLayer = new OpenLayers.Layer.WMS(

			        "EDIT Vmap0",

			        "http://edit.br.fgov.be:8080/geoserver/wms",

			        {layers: 'vmap0_world_basic', format:"image/png"},

			        {

						maxExtent: mapExtend_900913,

						isBaseLayer: true,

						displayInLayerSwitcher: true

					}

				);

			break;

			// create Google Mercator layers

			case 'gmap':

				baseLayer = new OpenLayers.Layer.Google(

					        "Google Streets",

					        {'sphericalMercator': true}

					    );

			break;

			case 'gsat':

				baseLayer = new OpenLayers.Layer.Google(

					        "Google Satellite",

					        {type: G_SATELLITE_MAP, 'sphericalMercator': true, numZoomLevels: 22}

					    );

			break;

			case 'ghyb':

				baseLayer = new OpenLayers.Layer.Google(

					        "Google Hybrid",

					        {type: G_HYBRID_MAP, 'sphericalMercator': true}

					    );

			break;

			case 'veroad':

				baseLayer = new OpenLayers.Layer.VirtualEarth(

					        "Virtual Earth Roads",

					        {'type': VEMapStyle.Road, 'sphericalMercator': true}

					    );

			break;

			case 'veaer':

				baseLayer = new OpenLayers.Layer.VirtualEarth(

					        "Virtual Earth Aerial",

					        {'type': VEMapStyle.Aerial, 'sphericalMercator': true}

					    );

			break;

			case 'vehyb':

				baseLayer = new OpenLayers.Layer.VirtualEarth(

					        "Virtual Earth Hybrid",

					        {'type': VEMapStyle.Hybrid, 'sphericalMercator': true}

					    );

			break;

			case 'yahoo':

				baseLayer = new OpenLayers.Layer.Yahoo(

					        "Yahoo Street",

					        {'sphericalMercator': true}

					    );

			break;

			case 'yahoosat':

				baseLayer = new OpenLayers.Layer.Yahoo(

					        "Yahoo Satellite",

					        {'type': YAHOO_MAP_SAT, 'sphericalMercator': true}

					    );

			break;

			case 'yahoohyb':

				 rebaseLayer = new OpenLayers.Layer.Yahoo(

					        "Yahoo Hybrid",

					        {'type': YAHOO_MAP_HYB, 'sphericalMercator': true}

					    );

			break;

			case 'mapnik':

				baseLayer = new OpenLayers.Layer.OSM();

			break;

			case 'oam':

				baseLayer = new OpenLayers.Layer.XYZ(

				        "OpenAerialMap",

				        "http://tile.openaerialmap.org/tiles/1.0.0/openaerialmap-900913/${z}/${x}/${y}.png",

				        {

				            sphericalMercator: true

				        }

				    );

			break;

			case 'osmarender':

				baseLayer = new OpenLayers.Layer.OSM(

				        "OpenStreetMap (Tiles@Home)",

				        "http://tah.openstreetmap.org/Tiles/tile/${z}/${x}/${y}.png"

				       );

			break;

		};

		return baseLayer;

	};

}

(function($){

	$.fn.cdm_openlayers_map = function(mapserverBaseUrl, options) {

		var opts = $.extend({},$.fn.cdm_openlayers_map.defaults, options);

		return this.each(function(){

			var openlayers_map = new CdmOpenlayersMap($(this), mapserverBaseUrl, opts);			

			openlayers_map.init();

	 	}); // END each

	}; // END cdm_openlayers_map

})(jQuery);

$.fn.cdm_openlayers_map.defaults = {  // set up default options

		legendPosition:  null,			// 1,2,3,4,5,6 = display a legend in the corner specified by the number

		displayWidth: 400,

		distributionOpacity: 0.75,

		legendOpacity: 0.75,

		boundingBox: null,

		showLayerSwitcher: false,

		baseLayerNames: ["osgeo_vmap0"],

		defaultBaseLayerName: 'osgeo_vmap0',

		maxZoom: 4,

		minZoom: 0

};