geonet-layergl

@geonet/layergl - WebGL for Leaflet Layers

Leaflet Layers with low-level WebGL shaders

Currently imagery adjustment suite support:

brightness (basic rgb color model adjustment)
contrast (michelson contrast algorithm)
sharpen (hysteresis thresholding and the laplace operator - laplacian kernel algorithm)
- tested the following algorithms and had poor results:
  - Sobel
  - Roberts
  - Laplacian of Gaussian
  - Robinson Compass
  - Zero-cross mask sharpening
  - Canny mask sharpening
  - gabor unmask sharpening
  - various multi-pass unmask sharpening methods
night vision (a mistake made when modifying the laplacian filter kernel, significantly brightens dark areas and slightly sharpens areas of high luminance contrast, resulting in a night-vision-like brightness and edge emphasis)

Experimental support:

dynamic range adjustment (work in progress - at the moment it only applies gamma correction and is not adaptive or dynamic)
edge detection (prewitt operator algorithm - can eventually be used for automated image-to-geometry edge detection and tagging)

Dream support:

one day, mapping data via WebGL could result in:

rotation (highly experimental and barely underway - map rotation support in Leaflet)
line-of-sight ("viewshed" or "line-of-sight" computing when served SRTM or other elevation based data)
other elevation data computations can be made on the fly with this module

Contribution:

This module is based on Ivan Sanchez's Leaflet.TileLayer.GL repo that appears to no longer be maintained.