gboolean a_file_save ( VikAggregateLayer *top, gpointer vp, const gchar *filename );
gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, gshort file_type );
gboolean a_file_save ( VikAggregateLayer *top, gpointer vp, const gchar *filename );
gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, gshort file_type );