import ee 
from ee_plugin import Map 

# NormalizedDifference example.
#
# Compute Normalized Difference Vegetation Index over MOD09GA product.
# NDVI = (NIR - RED) / (NIR + RED), where
# RED is sur_refl_b01, 620-670nm
# NIR is sur_refl_b02, 841-876nm

# Load a MODIS image.
img = ee.Image('MODIS/006/MOD09GA/2012_03_09')

# Use the normalizedDifference(A, B) to compute (A - B) / (A + B)
ndvi = img.normalizedDifference(['sur_refl_b02', 'sur_refl_b01'])

# Make a palette: a list of hex strings.
palette = ['FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718',
               '74A901', '66A000', '529400', '3E8601', '207401', '056201',
               '004C00', '023B01', '012E01', '011D01', '011301']

# Center the map
Map.setCenter(-94.84497, 39.01918, 8)

# Display the input image and the NDVI derived from it.
Map.addLayer(img.select(['sur_refl_b01', 'sur_refl_b04', 'sur_refl_b03']),
         {'gain': [0.1, 0.1, 0.1]}, 'MODIS bands 1/4/3')
Map.addLayer(ndvi, {'min': 0, 'max': 1, 'palette': palette}, 'NDVI')
