Abstract-In this paper, we provide a basic solution for online compression of data streams using error-bounded piecewiselinear approximation (PLA). We compare this method to the optimal (but offline) solution. Our current work in progress is developing an online PLA method that meets the same optimality constraints as the offline method. Also, the vertices of the constructed approximations are subsets of the sampled data points, which we believe to be a benefit in many scenarios.