Demonstrates pixelwise operations with a raster source.
This example uses a ol.source.Raster
to generate data
based on another source. The raster source accepts any number of
input sources (tile or image based) and runs a pipeline of
operations on the input pixels. The return from the final
operation is used as the data for the output source.
In this case, a single tiled source of imagery is used as input. For each pixel, the Triangular Greenness Index (TGI) is calculated from the input pixels. A second operation colors those pixels based on a threshold value (values above the threshold are green and those below are transparent).