[OpenLayers-Dev] Format.WMC questions

Andreas Hocevar ahocevar at opengeo.org
Sat Jul 11 16:23:21 EDT 2009

Hi Trond,

thanks for your work! read_wmc_LatLonBoundingBox can safely be removed. 
For the *URL nodes, I would prefer a common method. If you look at the 
WMC schema (http://schemas.opengis.net/context/1.1.0/context.xsd), you 
will see that there is a URLType. All URLType nodes could use the same 
reader function, and since runChildNodes adds some overhead, I would 
prefer this function like e.g. read_wmc_LegendType.

So we would have something like:

    readURLType: function(node) {
        var obj = {
            width: node.getAttribute('width'),
            height: node.getAttribute('height')
        var links = node.getElementsByTagName("OnlineResource");
        if(links.length > 0) {
            this.read_wmc_OnlineResource(obj, links[0]);
        return obj;

    read_wmc_LegendURL: function(style, node) {
        var legend = readURLType(node);
        style.legend = legend;


Trond Michelsen wrote:
> I'm currently working on adding parsing and writing of the remaining
> elements of Web Map Context documents, and there's something here that
> caught my eye.
> In read_wmc_MetaDataURL and read_wmc_LegendURL, the content of the
> OnlineResource element is read like this:
>   var links = node.getElementsByTagName("OnlineResource");
>   if(links.length > 0) {
>     this.read_wmc_OnlineResource(legend, links[0]);
>   }
> But afaict, this.runChildNodes(legend, node); should do the same. The
> only difference would be if there are more than one OnlineResource
> elements within the LegendURL og MetaDataURL elements, and there
> shouldn't be.
> Are there any particular reasons why these methods don't just call
> runChildNodes()? Should the methods for LogoURL, DescriptionURL and
> DataURL read the OnlineResource the same way, or is it OK that I use
> runChildNodes() in all methods?
> Also, there's a read_wmc_LatLonBoundingBox() method, but I can't find
> any LatLonBoundingBox element in the WMC standard. If it's OK, I'll
> just delete this method.

Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.

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