Virtual environment size & coordinates

I am trying to understand some of the features of the virtual dimensions. In particular, when defining the map in DeepMind Lab, what is the virtual length of an '*' (representing a wall segment) ? According to my calculations is *=100 but it seems it does not match those reported at: https://github.com/deepmind/lab/blob/master/docs/developers/creating_levels/text_level.md

Any help on these issues would be appreciated. Thanks!

EXAMPLE:
self._map = make_map.makeMap{
mapName = 'simple_arena',
mapEntityLayer =