The MapDrawableBatch class represents a single layer in a .tmx file. It implements the IDrawableBatch class to perform custom rendering. It internally creates a single vertex buffer which is drawn all at once with no render state changes for maximum performance.
Usually .tmx files are loaded into a LayeredTileMap, which contains one or more MapDrawableBatch instances.
Only painted tiles create vertices
When the MapDrawableBatch is created it will only create vertices for tiles which exist. Therefore tiles which are not painted or which have been erased in Tiled will not create vertices.