# Distance

A domain's Distance is the number of steps from that domain to the principal domain in the graph of links relationships for the ecosystem. Distance is key to determining the domain's domain type.

A nice way to understand distance is the game 'Six degrees of Kevin Bacon', where you pick an actor and then link them to another actor via a film they both appeared in; then you repeat this process until you reach Kevin Bacon. The number of films between your first actor and Kevin Bacon is the distance.

## Calculating distance

In the following illustration, domain A is 4 steps away from the principal domain (which appears on the left):

Often, there will be more than one path between a domain and the principal domain. In these cases, the domain's Distance value will be the length of the shortest path. In the following illustration, there are two paths between domain B and the the principal domain (which appears on the left):

Of the two available paths, the upper path is shorter (at 2 steps). So, the Distance for domain B is 2.

## Visualising Distance

In the main visualisation of a report interactive, the 'Distance' view re-colours the domains to indicate their Distance values.

## Viewing Distance values

All worksheets in the MS Excel file for a report that list domains contain a `Distance (lr)` column for this attribute. The `(lr)` at the end of the column name denotes that the value is calculated using the graph of links relationships.