The Tissue Saturation view is the answer to “why is the first stop there”. It plots the model’s compartments across the whole dive, against the gradient factors the plan was computed with.
Reading it
- A sparkline across the top follows the leading compartment’s gradient-factor percentage over the dive, with reference lines at the GF Low and GF High you set.
- The heat map below it holds one row per compartment, fast at the top and slow at the bottom, one column per moment, each cell coloured by how close that compartment is to its limit.
- Elapsed minutes run along the foot.
A trail links the leading compartment across the columns. The compartment nearest its limit is the one setting the ceiling, and which one that is changes as the dive runs: the fast compartments are in front early in the ascent, and by the shallow stops the slow ones have taken over, which is why lowering GF High costs so much more than lowering GF Low.
On a multi-level dive it is where a shallow second level stops looking like a rest. The fast compartments off-gas at 20 m while the slow ones are still loading.
What it does not show
The view draws the Bühlmann compartments and the gradient-factor limits. Under Thalmann E-L the ascent is decided a different way and the gradient factors have no effect on it, so you are looking at a Bühlmann picture of a dive that was not scheduled on Bühlmann. It is still informative about gas loading; it is not the constraint that produced the stops. See Decompression models.
On a rebreather
The graph follows the bailout selection. Select a scenario and the compartments plotted are that scenario’s: the tissue state at the bail point is inherited from the loop dive up to that moment, and everything after it is the open-circuit schedule.
Next
The models view is the last of the five. Tissue compartments covers what a compartment is and why there are sixteen of them.