$$LSI = \frac{e_{i}} {\min e_{i}}$$
where \(e_{i}\) is the total edge length in cell surfaces and \(\min e_{i}\)
is the minimum total edge length in cell surfaces.
LSI is an 'Aggregation metric'. It is the ratio between the actual edge length of
class i and the hypothetical minimum edge length of class i. The minimum edge length equals
the edge length if class i would be maximally aggregated.
Behaviour
Equals LSI = 1 when only one squared patch is present or all
patches are maximally aggregated. Increases, without limit, as the length of the
actual edges increases, i.e. the patches become less compact.