ee_ndvi.jl

using PyCall, Plots, Colors, FileIO;

# import the ee Python module into Julia
# and initialize the EE API
ee = pyimport("ee");
ee.Initialize();

# produce tabular data that can be plotted by data visualization in Julia
# Fetch a Landsat image.
img = ee.Image("LANDSAT/LT05/C01/T1_SR/LT05_034033_20000913");

# define a function to calcuate NDVI from an LT5 image
function ndvi(img)
    img.normalizedDifference(["B4","B3"]);
end

# apply function to image
ndvi_img = ndvi(img);

# define a color map to use for visualization
# choose green gradient and convert to hex color code
color_map = map(x -> hex(x,:RRGGBB), cgrad(:Greens_9));

# get a link to the thumbnail NDVI image
thumburl = ndvi_img.getThumbUrl(
    # define parameters to visualize image
    Dict(
        "min" => 0,
        "max" => 0.8,
        "dimensions" => 1024,
        "format" => "png",
        "palette" => color_map
    )
);

# download the image from the url returned
localpath = download(thumburl);

# load the image into an Array
img = FileIO.load(localpath);

# display the image
plot(img, ticks = nothing, border = :none)