In this paper we propose a technique called <i>storage-aware spatial </i>prefetching that can provide significant performance
improvements for out-of-core visualization. This approach is motivated by file <i>chunking</i> in which a
multidimensional data file is reorganized into multidimensional sub-blocks that are stored linearly in the file.
This increases the likelihood that data close in the n-dimensional volume represented by the file will be closer
together in the physical file. Chunking has been demonstrated to improve the typical access to such data, but it
requires a complete re-organization of the file and sometimes efficient access is only achieved if multiple different
chunking organizations are maintained simultaneously. Our approach can be thought of as <i>on-the-fly </i>chunking,
but it does not require physical re-organization of the data or multiple copies with different formats. We also
describe an implementation of our technique and provide some performance results that are very promising.