Terrain coverage algorithms are quite common in the computer science literature and for a good reason: they are able to deal with a diverse set of problems we face. From Web crawling to automated harvesting, from spell checking to area reconnaissance by unmanned aerial vehicles (UAVs), a good terrain coverage algorithm lies at the core of a successful approach to these and other problems. Despite the popularity of terrain coverage, none of the works in the field addresses the important issue of classification and evaluation of these algorithms. It is easy to think that all algorithms (since they are all called terrain coverage) deal with the same problem but this is a fallacy that this paper tries to correct. This paper presents a summary of many algorithms in the field, classifies them based on their goals, introduces metrics to evaluate them, and finally performs the evaluation.