We describe a new approach to scalable data analysis that enables scientists to manage the explosion in size and complexity of scientific data produced by experiments and simulations. Our approach uses a novel combination of efficient query technology and visualization infrastructure. The combination of bitmap indexing, which is a data management technology that accelerates queries on large scientific datasets, with a visualization pipeline for generating images of abstract data results in a tool suitable for use by scientists in fields where data size and complexity poses a barrier to efficient analysis. Our architecture and implementation, which we call DEX (short for dexterous data explorer), directly addresses the problem of "too much data" by focusing analysis on data deemed to be "scientifically interesting" via a user-specified selection criteria. The architectural concepts and implementation are applicable to wide variety of scientific data analysis and visualization applications. This paper presents an architectural overview of the system along with an analysis showing substantial performance over traditional visualization pipelines. While performance gains are a significant result, even more important is the new functionality not present in any visualization analysis software -- namely the ability to perform interactive, multi-dimensional queries to refine regions of interest that are later used as input to analysis or visualization.