Here is the scenario for these illustrations: Several boats want to anchor at the same fishing spot at a narrow place in a lake where only one boat will fit at a time. As the top figure shows, this is impossible because the boats cannot stack up on top of each other. Why can't GBrowse "stack the boats"?

The Algorithm The middle figure shows the first step in the Boats-on-a-Lake algorithm to correct this situation. The left-most boat stays put in this step; all of the other boats are pushed out to the right in order to make room for each boat on the surface of the lake. The bottom figure shows the next, and final, step in the algorithm. All of the boats are pushed to the left until the left-most and right-most boats are equidistant from the favored anchoring spot.

The "Duplications" Area

The red line below the boats in the bottom figure shows a duplications area. It is an area where there is not enough space to put all of the features which appear to go there, and where these features have been spread out to make room for them all.