getISOMetadataNamespace
gets a namespace given its id
getISOMetadataNamespace(id)
namespace prefix
getISOMetadataNamespace("GMD")
#> <ISOMetadataNamespace>
#> Public:
#> clone: function (deep = FALSE)
#> getDefinition: function ()
#> id: gmd
#> initialize: function (id, uri)
#> uri: http://www.isotc211.org/2005/gmd