WebGL Modules

The heart of deck.gl-raster is its WebGL modules. These building blocks give a huge amount of customizability, at the cost of a learning curve and ease of shooting yourself in the foot.

A series of modules defines a pipeline: a set of transformations that provide for what computations should be done on images in the GPU.

Note that it's easy to combine WebGL modules in such a way as to create an invalid pipeline, where you get WebGL errors instead of a useful result. The way to prevent these errors is to keep in mind the input dimensions and output dimensions and ensure that the output dimensions of one stage match the input dimensions of the next.

For example, you couldn't run normalizedDifference followed by pansharpenBrovey because the former transforms 2 dimensions to 1 and the latter takes 4 dimensions as input.

Pipeline stages

The easiest way to think about the pipeline is in two stages, a "create image" step and an "alter image" step. Every pipeline must have a "create image" step; most will also have an "alter image" step.

Create image

Load one or more images into an internal image object.

Use the modules provided in the Create Image page to load one or more images for transformations in the "Alter image" step.

Alter image

A set of operations to be done on the internal image object. At the end of this process, the image object will be rendered to the screen.

Explore the Alter Image documentation to see available transformations, or see the Custom Modules page to write your own.