[GRASS-git] [OSGeo/grass] db47aa: NDWI index added (#49)

[Markus Neteler]

  Branch: refs/heads/master
  Home:   https://github.com/OSGeo/grass
  Commit: db47aaca1961e48d3254089f12185fb4640e3c24
      https://github.com/OSGeo/grass/commit/db47aaca1961e48d3254089f12185fb4640e3c24
  Author: Markus Neteler <neteler at gmail.com>
  Date:   2019-07-13 (Sat, 13 Jul 2019)

  Changed paths:
    M imagery/i.vi/i.vi.html
    M imagery/i.vi/main.c
    A imagery/i.vi/ndwi.c
    M imagery/i.vi/testsuite/test_vi.py

  Log Message:
  -----------
  NDWI index added (#49)

* NDWI index added

NDWI (Normalized Difference Water Index) after McFeeters (1996), https://doi.org/10.3390/rs5073544

* NDWI added to testsuite/test_vi.py

* NDWI example: set color table