We propose a new online collaborative tool for visually understanding national health indicators, which facilitates the full spectrum of investigation of indicators, from an overview of all the correlation coefficients between variables, to investigation of subsets of selected variables, and to individual data element analysis. This tool is publicly accessible at https://cda.ornl.gov/heat/heatmap.html. In this paper, we discuss the key issues regarding the interface design and implementation. We also illustrate how to use our interface for analyzing the health indicator dataset by showing some key system views. In the end, we introduce and discuss some ongoing research efforts extending this work.