Vizzlo is a browser-based tool to create professionally designed charts, graphics, and with more than 75 chart types (timelines, Gantt-chart, milestones plans, waterfall-chart, etc.) Plotly is the easiest way to graph and share data online. Gantt chart. Section refers to the project's section (useful for large projects, with milestones). Line refers to a Interactive Visualization - Plotly https://p ot. y/ggp Gantt Charts in Python. How to make Gantt Charts in Python with Plotly. Gantt Charts use horizontal bars to represent the start and end times of tasks. A Gantt chart is a type of bar chart that illustrates a project schedule. The chart lists the tasks to be performed on the vertical axis, and time intervals on the horizontal axis.