如何绘制等边三角形?

时间:2013-04-16 13:15:45

标签: matlab plot matlab-figure triangulation delaunay

我想在MATLAB中制作一个类似于这个图的颜色图:

http://1.bp.blogspot.com/-QpFb-Yj_MOg/UA4Tw3xuVVI/AAAAAAAAAIQ/T3kTUT39c-A/s1600/triangular+plot.png

我已设法创建所需的所有点[x,y]以创建顶点,并且我有一个包含每个顶点颜色的地图,所以我可以得到以下内容。

Correct plot, but wrong axes

但我不明白如何使轴工作。

到目前为止

代码:

% Equilateral grid 
tcorner = [0.0, 0.5,           1.0;
           0.0, 1.0*sqrt(3)/2, 0.0];
tg = triangle_grid( 1/0.05, tcorner );
tgx = tg(1,:);
tgy = tg(2,:);

% Create triangles
tri = delaunay(tgx,tgy);

% Plot
h = trisurf(tri, tgx, tgy, colorvector);

网格功能:

function triangle_grid(n, tcorner)
    ng = ( ( n + 1 ) * ( n + 2 ) ) / 2;
    tg = zeros ( 2, ng );

    p = 0;

    for i = 0 : n
        for j = 0 : n - i
            k = n - i - j;
            p = p + 1;
            tg(1:2,p) = ( i * t(1:2,1) + j * t(1:2,2) + k * t(1:2,3) ) / n;
        end
    end
end

1 个答案:

答案 0 :(得分:0)

主要问题是您无法将轴旋转到正确位置,因为始终会向下侧翻转。所以,你需要创建它们。

以下是:

% Equilateral grid 
tcorner = [0.0, 0.5, 1.0; % x
           0.0, 1.0*sqrt(3)/2,   0.0]; % y
tg = triangle_grid( 1/0.05, tcorner);
tgx = tg(1,:);
tgy = tg(2,:);

% Create triangles
tri = delaunay(tgx,tgy);
col = rand(size(tgx));
trisurf(tri,tgx,tgy,col)
view(0,90)
colormap('lines')

% setting the axes:
ax = gca;
grid off
ax.YAxis.Visible = 'off';
ticks = (0:20:80).';

% bottom axis:
tickpos = linspace(tcorner(1,1),tcorner(1,3),numel(ticks)+1);
ax.XAxis.FontSize = 14;
ax.XAxis.TickValues = tickpos(1:end-1);
ax.XAxis.TickLabels = ticks;
ax.XAxis.TickLabelRotation = 45;
xlabel('X axis title');

% left & right axis:
ticksxpos = linspace(tcorner(1,1),tcorner(1,3),numel(ticks)*2+1);
ticksypos = linspace(tcorner(2,1),tcorner(2,2),numel(ticks)+1);
text(ticksxpos(numel(ticks)+1:-1:2)-0.03,... % left
    ticksypos(end:-1:2)+0.03,...
    num2str(ticks),'FontSize',14,...
    'VerticalAlignment','bottom',...
    'HorizontalAlignment','left',...
    'Rotation',-45)
text(ticksxpos(end:-1:numel(ticks)+2)+0.05,... % right
    ticksypos(1:end-1)-0.03,...
    num2str(ticks),'FontSize',14,...
    'VerticalAlignment','bottom',...
    'HorizontalAlignment','right')
ax.Parent.Color = 'w';

% titles:
text(tcorner(1,2)/2-0.06,tcorner(2,2)/2+0.06,...
    'Left title','FontSize',14,...
    'HorizontalAlignment','center',...
    'Rotation',45)
text(tcorner(1,2)+tcorner(1,2)/2+0.06,tcorner(2,2)/2+0.06,...
    'Right title','FontSize',14,...
    'HorizontalAlignment','center',...
    'Rotation',-45)

我们得到......

tiangular