sankeyDemo17_2.m

%% sankey demo17_2 : Land use transition sankey diagram
% -----------------------
% gitee/github      : slandarer
% fileexchange      : Zhaoxu Liu / slandarer
% 公众号            : slandarer随笔
% 知乎              : slandarer

% 本示例来源于微信公众号「图绘科研」的原创教程
% 《图绘科研｜MATLAB科研绘图：土地利用转移桑基图绘制教程》，作者为 QDY

layerNames = {'2005', '2010', '2015', '2020'};
nodeNames  = {'耕地', '林地', '草地', '水域', '建设用地', '未利用地'};
LN = length(layerNames); NN = length(nodeNames);

nodeTitle  = '土地利用类型';
CList = [.86, .70, .45;   % 耕地：浅棕色
    .35, .62, .35;   % 林地：绿色
    .68, .80, .45;   % 草地：黄绿色
    .45, .72, .88;   % 水域：蓝色
    .86, .42, .38;   % 建设用地：红橙色
    .68, .64, .58];  % 未利用地：灰褐色
T12 = [300,  35,  20,  5, 55,  5;
    20, 230,   5,  5,  0,  0;
    25,  10, 130,  5,  5,  5;
    2,   5,   3, 48,  2,  0;
    20,   0,   2,  0, 98,  0;
    13,   5,  10,  2, 10, 30];  % 2005 -> 2015
T23 = [300,  15,  10,  5,  45,  5;
    10, 260,   5,  5,   5,  0;
    15,  10, 125,  3,  12,  5;
    1,   3,   2, 58,   1,  0;
    18,   2,   3,  1, 145,  1;
    6,  10,  15,  3,  12, 14]; % 2015 -> 2020
T34 = [300,  10,   6,  4,  28,  2;
    5, 285,   4,  5,   1,  0;
    10,  12, 120,  4,   9,  5;
    1,   5,   2, 60,   2,  0;
    12,   2,   3,  1, 202,  0;
    2,   1,  15,  1,   8, 23]; % 2020 -> 2022

% 获取全局邻接矩阵 (Assemble global block matrix)
layerAdj = {T12, T23, T34};
adjMat = mergeAdjMat(layerAdj);

% 创建图窗和坐标区域 (Create figure and axes)
fig = figure('Name','sankey demo17_2', 'Position',[50, 100, (LN - 1)/2*800, 800], 'Color','w');
for i = 1:(LN - 1)
    axC{i} = axes('Parent',fig, 'Position',[.04 + (i - 1).*.92/(LN - 1), .5, .92/(LN - 1), .44]);
end
axS = axes('Parent',fig, 'Position',[.04, .06, .92, .44]);

% 计算节点流量 (Compute node values)
nodeVal = zeros(NN, LN);
for i = 1:(LN - 1)
    nodeVal(:, i)     = max(nodeVal(:, i), sum(layerAdj{i}, 2)); 
    nodeVal(:, i + 1) = max(nodeVal(:, i + 1), sum(layerAdj{i}, 1).');
end

% 创建桑基图对象 (Create sankey plot object)
SK = SSankey(axS, [],[],[], 'AdjMat',adjMat);
SK.RenderingMethod = 'left';                 % 链接与左侧节点颜色相同 (Rendering Method : 'left')
SK.ColorList = repmat(CList, [LN, 1]);       % 为每个节点分配颜色 (Assign colors to all nodes)
SK.NodeList = cellstr(num2str(nodeVal(:)));  % 设置节点标签 (Set node labels)
SK.LabelLocation = 'left';                   % 设置节点标签位于左侧 (Place labels on left side)
SK.draw()
axis(axS, 'tight')

% 添加层标签 (Add layer labels)
text(axS, 1:LN, zeros(1, LN), layerNames, ...
    'HorizontalAlignment','center', 'VerticalAlignment','top', ...
    'FontName','Times New Roman', 'FontSize',17, 'FontWeight','bold')


% 绘制弦图 (Draw sankey diagrams)
for i = 1:(LN - 1)
    tCC = biChordChart(axC{i}, layerAdj{i}, 'Arrow','on');
    tCC.Label = nodeNames;
    tCC.CData = CList;
    tCC.draw();

    title(axC{i}, ['From ', layerNames{i}, ' To ', layerNames{i + 1}], ...
        'HorizontalAlignment','center', 'VerticalAlignment','bottom', ...
        'FontName','Times New Roman', 'FontSize',17, 'FontWeight','bold')
end