The trace of a projection matrix is the dimension of the target space.

A projection matrix therefore has spread or .

Then, we can see how the Schur complements are connected to the projection matrices of the symmetric, partitioned matrix.

More precisely, let be the projection matrix of a camera and be the image projection of , i.e. .

An example function is which defines a two dimensional orthographic projection matrix.

The orthogonal projection can be represented by a projection matrix.

In an ideal pinhole camera, a simple projection matrix is enough to do this.

The square optimal projection matrix with dimension is central to the OPE.

The field of population ecology often uses data on life history and matrix algebra to develop projection matrices on fecundity and survivorship.

Centering matrix, which is an example of a projection matrix.