fixed the grid representation.

- cropped top and bottom for better comparison
- although the resulting grids are wavy, it's the
  result of the aggregation.
- will need to prepare a mock data to show this behaviour

Signed-off-by: Nicholas Tan Jerome <nicholas.jerome@kit.edu>
added log.txt into ignore list

- log.txt is only used to output data to be examined
  externally.

Signed-off-by: Nicholas Tan Jerome <nicholas.jerome@kit.edu>