© Pedro Pereira Gonçalves
(pedro@inovagis.org)
Version : 0.3
Last Change : 2003-10-27
File Name : WMSlayer.js

layerWMS
    Image-type class that makes a single request and OGC WMS server with one or more layers.

    create method: function layerWMS(parent, url, layer, caption, version)

    Creates the layerWMS class that defines the WMS layer properties and methods according to the OpenGIS specification, where the parameters are:
    • parent - class defining the control where the layer will be integrated can be null or an instant of mapWMS and its descendents
    • url - server url (without the http)
    • layer - layer name or names
    • caption - optional parameter for future use on legends and display box
    • version - optional parameter defining the wms version (default value is "1.1")

    Methods
    • url = function (BBox)
      returns the OGC WMS compliant url for this request. The BBox is optional parameter. When null and this class parent is a mapWMS (or any of its descendents) his own BBox value will be used

    • writeDOM = function (name, left, top, width, height, style)
      Writes the necessary DHTML for this class (to-do still needs implement the style tag)

    • refresh = function (BBox)
      Updates the image HTML element with a new request (updating any changes made to the class)

    • show = function () - not fully implemented

    • hide = function () - not fully implemented

    • isVisible = function () - not fully implemented


    Properties
    • parent : class defining the control where the layer will be integrated can be null or an instant of mapWMS and its descendents

    • srs : defines the spatial reference system of the request (default value is "EPSG:4326" or the parent's value if different than null)

    • wmsUrl : Url of the server (without the http)

    • wmsLayers : string defining the layer name or names;

    • caption : string defining the caption to be used in future implementations for the legend and configuration object

    • format : (default value is "GIF")

    • opacity : not fully implemented

    • styles : string defining the layer(s) style(s) (default value is "")

    • additionalParam : additional or vendor specific parameters to add to the url (default value is "")

    • visible : boolean value defining the objects visibility (default value is "true")

    • version : WMS version to be used to this request

    • request : string that defines the url parameters of the WMS that are version-dependent (e.g. WMTVER and REQUEST)

    • DOMref : reference to the image DOM object that is created on the writeDOM method.

    • directLoading : Added the option to select direct loading without using the transport image by default is false in all browsers except in IE 6 (because this browsers will always recall the image even if it has an object in memory)

    Events
    • onError = function ( wmsLayer ) : event launched when a http connection error occurs

    Examples
    • single layer request example [view]

    Change Log
    • 2003-10-27 : When in directLoading mode the image source is first cleared using the empty_img and only then goes to the wms url (once again thanks to Bart)
    • 2003-10-24 : Added the option to select direct loading without using the transport image by default is false in all browsers except in IE 6 (because this browsers will always recall the image even if it has a object in memory)
    • 2003-10-10 : In url function forces the use of the BBox input parameter if exists
    • 2003-09-09 : Change the add layer method so that accepts relative urls (*)
    • 2003-06-25 : Documentation added
    • 2003-04-28 : writeDOM method added to layerWMS added the onerror event