Greenland ice loss example: animated & interactive

using Tyler
using Tyler.TileProviders
using Tyler.Extents
using Dates
using HTTP
using Arrow
using DataFrames
using GLMakie
using GLMakie.Colors
GLMakie.activate!()

INFO

Ice loss from the Greenland Ice Sheet: 1972-2022.

• Contact person: Alex Gardner & Chad Greene

Load ice loss data [courtesy of Chad Greene @ JPL]

url = "https://github.com/JuliaGeo/JuliaGeoData/blob/365a09596bfca59e0977c20c2c2f566c0b29dbaa/assets/data/iceloss_subset.arrow?raw=true";
resp = HTTP.get(url);
df = DataFrame(Arrow.Table(resp.body));
first(df, 5)

5×3 DataFrame

Row	X	Y	Date
	SubArray…	SubArray…	DateTime
1	[-5.86725e6, -5.86687e6, -5.86648e6, -5.86609e6, -5.86753e6, -5.75864e6, -5.7174e6, -5.71703e6, -5.71665e6, -5.71924e6 … -5.6051e6, -5.60477e6, -5.60444e6, -5.60411e6, -5.60378e6, -5.60345e6, -5.60312e6, -5.60279e6, -5.60246e6, -5.60213e6]	[1.17525e7, 1.17526e7, 1.17526e7, 1.17527e7, 1.17517e7, 1.1661e7, 1.15656e7, 1.15656e7, 1.15657e7, 1.1565e7 … 1.07214e7, 1.07214e7, 1.07214e7, 1.07215e7, 1.07215e7, 1.07215e7, 1.07215e7, 1.07216e7, 1.07216e7, 1.07216e7]	1972-10-15T00:00:00
2	[-5.8672e6, -5.86681e6, -5.86643e6, -5.86748e6, -5.76523e6, -5.71736e6, -5.71699e6, -5.71661e6, -5.7192e6, -5.71882e6 … -5.60639e6, -5.60606e6, -5.60573e6, -5.6054e6, -5.60507e6, -5.60408e6, -5.60375e6, -5.60342e6, -5.60309e6, -5.60276e6]	[1.17521e7, 1.17522e7, 1.17522e7, 1.17513e7, 1.16579e7, 1.15652e7, 1.15652e7, 1.15653e7, 1.15646e7, 1.15647e7 … 1.07209e7, 1.07209e7, 1.0721e7, 1.0721e7, 1.0721e7, 1.07211e7, 1.07212e7, 1.07212e7, 1.07212e7, 1.07212e7]	1972-11-15T00:00:00
3	[-5.86715e6, -5.71732e6, -5.71694e6, -5.71657e6, -5.71765e6, -5.72354e6, -5.72316e6, -5.71865e6, -5.72633e6, -5.72729e6 … -5.56852e6, -5.5695e6, -5.5639e6, -5.56258e6, -5.56271e6, -5.60087e6, -5.60441e6, -5.60372e6, -5.60339e6, -5.60306e6]	[1.17517e7, 1.15648e7, 1.15649e7, 1.15649e7, 1.15644e7, 1.15626e7, 1.15627e7, 1.15632e7, 1.15604e7, 1.15588e7 … 1.08169e7, 1.08165e7, 1.08143e7, 1.08107e7, 1.08083e7, 1.07224e7, 1.07211e7, 1.07208e7, 1.07209e7, 1.07209e7]	1972-12-15T00:00:00
4	[-5.71728e6, -5.7169e6, -5.71653e6, -5.71761e6, -5.71941e6, -5.71903e6, -5.63901e6, -5.62706e6, -5.59818e6, -5.59062e6, -5.59024e6, -5.58989e6, -5.59155e6, -5.56301e6, -5.60474e6, -5.60405e6]	[1.15645e7, 1.15645e7, 1.15645e7, 1.1564e7, 1.15631e7, 1.15631e7, 1.12759e7, 1.12427e7, 1.10848e7, 1.10753e7, 1.1075e7, 1.1075e7, 1.09937e7, 1.0808e7, 1.07211e7, 1.07208e7]	1973-01-15T00:00:00
5	[-5.71724e6, -5.71686e6, -5.71795e6, -5.59853e6, -5.59027e6, -5.58992e6, -5.59152e6, -5.60438e6]	[1.15641e7, 1.15641e7, 1.15636e7, 1.10848e7, 1.10753e7, 1.10753e7, 1.09934e7, 1.07208e7]	1973-02-15T00:00:00

select map provider

provider = TileProviders.Esri(:WorldImagery);

Greenland extent

extent = Extent(X = (-54., -48.), Y = (68.8, 72.5));

Extent(X = (-54.0, -48.0), Y = (68.8, 72.5))

extract data

cnt = [length(foo) for foo in df.X];
X =  reduce(vcat,df.X);
Y =  reduce(vcat,df.Y);
Z = [repeat([i],c) for (i, c) = enumerate(cnt)];
Z = reduce(vcat,Z);

make a colormap

nc = length(Makie.to_colormap(:thermal));
n = nrow(df);
alpha = zeros(nc);
alpha[1:maximum([1,round(Int64,1*nc/n)])] = alpha[1:maximum([1,round(Int64,1*nc/n)])] .* (1.05^-1.5);
alpha[maximum([1,round(Int64,1*nc/n)])] = 1;
cmap = Colors.alphacolor.(Makie.to_colormap(:thermal), alpha);
cmap = Observable(cmap);

show map

fig = Figure(; size = (1200,600))
ax = Axis(fig[1,1])
m = Tyler.Map(extent; provider, figure=fig, axis=ax)

create initial scatter plot

scatter!(ax, X, Y; color = Z, colormap = cmap, colorrange = [0, n], markersize = 10);
m

add colorbar

a,b = extrema(df.Date);
a = year(a);
b = year(b);
Colorbar(fig[1,2]; colormap = cmap, colorrange = [a,b],
    height=Relative(0.5), width = 15)
# hide ticks, grid and lables
hidedecorations!(ax);
# hide frames
hidespines!(ax);
m

loop to create animation

for k = 1:15
    # reset apha
    alpha[:] = zeros(nc);
    cmap[] = Colors.alphacolor.(cmap[], alpha)
    for i in 2:1:n
        # modify alpha
        alpha[1:maximum([1,round(Int64,i*nc/n)])] = alpha[1:maximum([1,round(Int64,i*nc/n)])] .* (1.05^-1.5);
        alpha[maximum([1,round(Int64,i*nc/n)])] = 1;
        cmap[] = Colors.alphacolor.(cmap[], alpha);
        sleep(0.001);
    end
end