This type of footing has the advantage that it can be stepped in brickwork or blockwork increments so that it can easily be adapted to sloping sites.

Above is a sectional detail of reinforced concrete footing showing some of the requirements for the design. Any drawing like this only tells part of the story. The specifications will also details like:-

Stripping off the vegetation and topsoil layer.

The minimum bearing capacity of the subgrade.

The compaction of the fill inside the building and the back-fill outside.

The strength of the concrete and the corefill.

The contract specifications in their turn will call up regulatory standards like and building codes that the concrete, the reinforcing steel, the vapour barrier, the termite protection method etc etc.