帮我检查一下这段代码 clc clear fname='G:\CMIP6 data\map_hed\ACCESS-CM2\ssp126.xlsx'; [data]=xlsread(fname); lat = ncread('G:\CMIP6 data\CMIP6_china\Precipitation\ACCESS-CM2 (Australia)\pr_day_ACCESS-CM2_ssp126_r1i1p1f1_gn_20150101-21001231_v20191108.nc','lat'); lon = ncread('G:\CMIP6 data\CMIP6_china\Precipitation\ACCESS-CM2 (Australia)\pr_day_ACCESS-CM2_ssp126_r1i1p1f1_gn_20150101-21001231_v20191108.nc','lon'); %% filename4=('E:\XB\xibei\NewFolder\xeibei84.shp');%E:\XB\xibei\xb_wang Shape=shaperead(filename4); Sx=Shape.X;Sy=Shape.Y; data1=data'; for g=1:length(lat) x=lat(g); for h=1:length(lon) y=lon(h); U=inpolygon(x,y,Sy,Sx); if U==0 data1(g,h,:)=nan; end end end %% % filename=shaperead('E:\XB\xibei\NewFolder\xb_line.shp'); % geoshow(filename) m_proj('miller','longitudes',[72 112], 'latitudes',[33 51]); u=m_pcolor(lon,lat,data1); colormap('autumn'); caxis([5,30]);%pr 3*4=12 m_grid('FontSize',10,'Fontname','Times New Roman'); % m_grid('FontSize',10,'Fontname','Times New Roman','xticklable',[]); handles=findobj(gca,'tag','m_grid_yticklabel'); delete(handles(1:2:end)); handles=findobj(gca,'tag','m_grid_xticklabel'); delete(handles(1:2:end)); % m_grid('linestyle','none'); set(u,'edgecolor','none');%? colorbar map=shaperead('E:\XB\xibei\NewFolder\xb_line.shp');%加载省界带南海的边界线 xb_x=[map(:).X];%提取经度 xb_y=[map(:).Y];%提取纬度 provence=[xb_x',xb_y']; plot(xb_x,xb_y,'-k','LineWidth',1.2);%绘国界 axis([72 112 33 51]);%设置显示的经纬度范围 hold off

这段代码中有一些错误：

1.在加载shp文件时，使用了不同的变量名：`fname`和`filename4`。应该保持一致。

2.在加载shp文件时，没有指定要读取的形状文件类型。应该使用`shaperead`函数的第二个输入参数指定类型，例如：`Shape=shaperead(filename4,'UseGeoCoords',true,'Selector',{@(name) strcmp(name,'Polygon')},'Attributes',{'X','Y'})`。

3.在使用`m_pcolor`函数时，应该将纬度和经度矩阵转置，即使用`[lon,lat]=meshgrid(lon,lat)`。

4.在绘制地图时，应该先用`m_proj`函数设置投影方式，再使用`m_grid`函数绘制网格线和标签。

5.在绘制地图时，应该使用`hold on`命令保留图形。

下面是修改后的代码：

clc
clear

% 加载Excel文件
fname = 'G:\CMIP6 data\map_hed\ACCESS-CM2\ssp126.xlsx';
[data] = xlsread(fname);

% 加载经纬度信息
lat = ncread('G:\CMIP6 data\CMIP6_china\Precipitation\ACCESS-CM2 (Australia)\pr_day_ACCESS-CM2_ssp126_r1i1p1f1_gn_20150101-21001231_v20191108.nc','lat');
lon = ncread('G:\CMIP6 data\CMIP6_china\Precipitation\ACCESS-CM2 (Australia)\pr_day_ACCESS-CM2_ssp126_r1i1p1f1_gn_20150101-21001231_v20191108.nc','lon');

% 加载shp文件
filename4 = 'E:\XB\xibei\NewFolder\xeibei84.shp';
Shape = shaperead(filename4,'UseGeoCoords',true,'Selector',{@(name) strcmp(name,'Polygon')},'Attributes',{'X','Y'});
Sx = Shape.X;
Sy = Shape.Y;

% 将数据矩阵转置
data1 = data';

% 标记在外部的数据点设置为NaN
for g = 1:length(lat)
    x = lat(g);
    for h = 1:length(lon)
        y = lon(h);
        U = inpolygon(x,y,Sy,Sx);
        if U == 0
            data1(g,h,:) = nan;
        end
    end
end

% 绘制地图
figure
m_proj('miller','longitudes',[72 112], 'latitudes',[33 51]);
hold on
[lon,lat]=meshgrid(lon,lat);
u = m_pcolor(lon,lat,data1);
colormap('autumn');
caxis([5,30]);%pr 3*4=12
m_grid('FontSize',10,'Fontname','Times New Roman');
handles = findobj(gca,'tag','m_grid_yticklabel');
delete(handles(1:2:end));
handles = findobj(gca,'tag','m_grid_xticklabel');
delete(handles(1:2:end));
map = shaperead('E:\XB\xibei\NewFolder\xb_line.shp');
xb_x = [map(:).X];
xb_y = [map(:).Y];
provence = [xb_x',xb_y'];
plot(xb_x,xb_y,'-k','LineWidth',1.2);
axis([72 112 33 51]);
hold off