BUG: Implement GeomMetadataSupplier::GetNbBands

Modules/Core/Metadata/include/otbGeomMetadataSupplier.h

@@ -48,6 +48,7 @@ public:
   GeomMetadataSupplier(const std::string &);
   GeomMetadataSupplier(const GeomMetadataSupplier &) = delete;
   GeomMetadataSupplier& operator=(const GeomMetadataSupplier&) = delete;
+  ~GeomMetadataSupplier() = default;
 
   /**
    * @brief Get the metadata value corresponding to a given path

Modules/Core/Metadata/src/otbGeomMetadataSupplier.cxx

@@ -52,7 +52,7 @@ std::string GeomMetadataSupplier::GetResourceFile(std::string) const
 
 int GeomMetadataSupplier::GetNbBands() const
 {
-  return 0;
+  return this->GetAsVector<std::string>("support_data.band_name_list").size();
 }
 
 const boost::any& GeomMetadataSupplier::FetchRPC(ImageMetadata & imd)