big vector graphics

[Colx007]

How do indicate to QGraphicsView that print a function z(x, y) or any matrix,
where Matrix = Data[however][3] and Z is positive in depth ?

By example:

X Y Z
1 1 1
1 2 1
2 1 0



I know to use the data, I don’t know anything about QGraphicsItem and I read tutorial.
Please, put a single example.

PD: By the way “however” is > 140,000.