使用 mapshow MatLab 使 NaN 变白

Question

我在 MatLab 中使用 mapshow，但我有一些没有数据的多边形，我想将其留空（即颜色为白色）。现在它显示默认的黄色。我能做什么？

link 与 NaN 映射：https://i.stack.imgur.com/fyr82.png

下面的可重现代码，

      MapLatLimit = [41 48];
MapLonLimit = [-74 -66];

NEstates = shaperead('usastatelo', 'UseGeoCoords', true, 'BoundingBox', [MapLonLimit' MapLatLimit']);
fall = flipud(bone(numel(NEstates)));
datawithNaN = num2cell([10 20 30 NaN 40 50 NaN NaN]);
    [NEstates.datawithNaN] =  deal(datawithNaN{:});
densityColors = makesymbolspec('Polygon', {'datawithNaN',   [0 50], 'FaceColor', fall});
mapshow(NEstates, 'DisplayType', 'polygon',  'SymbolSpec', densityColors)

Answer 1

我自己找到了解决方案。将 'NaN' 本身视为一个类别，然后为其分配颜色。下面的代码。

      MapLatLimit = [41 48];
MapLonLimit = [-74 -66];

NEstates = shaperead('usastatelo', 'UseGeoCoords', true, 'BoundingBox', [MapLonLimit' MapLatLimit']);
datawithNaN = [30 20 30 NaN 40 50 NaN NaN];
% Here replace NaNs with a number (treat as category):
datawithNaN(isnan(datawithNaN)) = 0;
datawithNaN = num2cell(datawithNaN);

% Here I create a color map, using white for NaN (category = 0);
mycolormap = [  1 1 1;...
               .4 .1 .9;...
               .3 .2 .8;...
               .2 .3 .7;...
               .1 .4 .6];
[NEstates.datawithNaN] =  deal(datawithNaN{:});
densityColors = makesymbolspec('Polygon', {'datawithNaN',   [0 50], 'FaceColor', mycolormap});
mapshow(NEstates, 'DisplayType', 'polygon',  'SymbolSpec', densityColors)

使用 mapshow MatLab 使 NaN 变白

Make NaN white with mapshow MatLab

mapping

matlab

colors

nan