geonet-layergl

@geonet/layergl - WebGL for Leaflet Layers

Demo

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.