Multi-track Visualizations
In Tutorial 1, we introduce how to load data, encode data with marks, transform data, overlay multiple marks and obtain the following visualization.
This tutorial continues from this example and introduces more advances functions:
Semantic Zooming​
Apart from the default zoom and pan interactions, semantic zoom is supported in Gosling and allows users to switch between different visualizations of the same data through zooming in/out. When zooming in, the same data will be represented in a different way in which more details are shown.
Let's say, for this visualization, we want text annotations to show up when zooming in.
We add text marks to the overlay property and specify when the text marks should appear through the visibility property.
We may wish the text marks to appear when the distance between chromStart and chromEnd is big enough to place a text mark.
In other words, the text marks appear when the width (measure) of the text mark (target) is less than (operation) than |xe-x|.
Multiple Linked Tracks​
We may wish to represent the same data from different aspects using different types of visualization.
To achieve this, we add an area chart (i.e., a new track) to the tracks property.
Since these tracks share the same x coordinate, we wish to link these two tracks: the zooming and panning performed in one track will be automatically applied to the linked track.
In Gosling, tracks can be linked by assigning x the same linkingId.
Circular Layout​
We can easily turn the visualization into a circular layout through the layout property.