Visualizing Large Datasets in TOPCAT v4

Abstract. TOPCAT is a widely used desktop application for manipulation of astronomical catalogs and other tables, which has long provided fast interactive visualization features including 1, 2 and 3-d plots, multiple datasets, linked views, color coding, transparency and more. In Version 4 a new plotting library has been written from scratch to deliver new and enhanced visualization capabilities. This paper describes some of the considerations in the design and implementation, particularly in regard to providing comprehensible interactive visualization for multi-million point datasets.