ENH: code review fix

Modules/Core/ImageBase/include/otbImageCommons.h

@@ -77,7 +77,7 @@ public:
   /** Returns true if a sensor geometric model is present */
   bool HasSensorGeometry() const;
 
-protected:
+private:
   ImageMetadata m_Imd;
 };
 

Modules/Core/ImageBase/src/otbImageCommons.cxx

@@ -49,6 +49,7 @@ void ImageCommons::SetProjectionRef(const std::string& proj)
 
 std::string ImageCommons::GetGCPProjection(void) const
 {
+  assert(m_Imd.Has(MDGeom::GCP));
   return m_Imd.GetGCPParam().GCPProjection;
 }
 
@@ -65,6 +66,7 @@ unsigned int ImageCommons::GetGCPCount(void) const
 
 const OTB_GCP& ImageCommons::GetGCPs(unsigned int GCPnum) const
 {
+  assert(GCPnum < GetGCPCount());
   return m_Imd.GetGCPParam().GCPs[GCPnum];
 }