A chart is displayed without rendering entirely obscured markers. Successive nested pixel maps of a chart of pixels are traversed. Each of the nested pixel maps has fewer data elements than a corresponding next one of the nested pixel maps. Obscurity states of markers of the chart are determined. The obscurity states include an entirely obscured state, an entirely visible state, and a partially visible state. Each of the markers for a particular nested pixel map is associated with a separate pixel for the particular nested pixel map. One or more of the markers associated with the entirely visible state and one or more of the markers associated with the partially visible state are rendered without rendering markers associated with the entirely obscured state.