As one of the key issues in geography and ecology, scaling has been drawing more and more attention, and it’s very necessary to grasp its fundamental issues. So, based on the relative articles, this paper dwells on the general issues in scaling, including concept, sorts, characters, basic theories, key problems and study strategies.
Scaling is the process of extrapolating or translating information from one scale to another, and the essential characters of which are scale dependency, model nonlinearness and complexity in study, the basic theories are hierarchy theory, fractal theory, etc. From the relative studies on scaling, we can find out there are some key problems in scaling, such as scale selection & information extraction, domains of scale & characteristic scale, modelling, and so on. The study strategies are different in different situations. In the process of extrapolating information across adjacent scales, there are three methods: ①change the model’s grain, extent or both directly;②modify the model before changing it’s grain and extent.③based on the mutual relations of the background factors in different scales. As for the cases of extrapolating information across a wide range of scales, what we can do is to study one scale after another and get the last scale information from all the other scales’ information. For the future of scaling, we need common communication among subjects and innovations in theories and technologies.