HRTEM images are traditionally interpreted by comparing experiment and simulation. However, quantitative agreement between experimental and simulated images is rarely achieved. It is thus highly desirable to extract quantitative information from HRTEM lattice images directly, without recourse to simulated images. Such 'direct' methods have been used to obtain high-resolution composition maps from the local information content of HRTEM images. We review the real-space techniques QUANTITEM and chemical mapping and delineate their application range. Finally, we demonstrate that both methods can be regarded as limiting cases of a more general approach.