generate my image with geographic coordinates by using limited latitude and longitude :
myimage = unifrnd(0,1,100,100); % 要存的图片,此处随机生成一个矩阵作示例
latlim = [-90,90];
lonlim = [-180,180];
R = georefcells(latlim,lonlim,size(myimage)); % 设置一个地理坐标
geotiffwrite('myimage.tif', myimage, R); % 存入图片myimage.tif