[ncl-talk] questions about drawing contours with map

[李雯雯]

Hello !
I have a matrix which represents a certain quantity ,each point in the matrix has the corresponding latitude and longitude.The longitude of each column in the matrix is not necessarily equal,the latitude of each line is also not necessarily equal.I want to draw contours which are overlaid the map and the latitude and longitude grid lines like the fig1 which may have bent and inclined grid lines and  the shading area is  rectangular, but I failed to draw the picture like the fig2. Is there any way to correct it? I appreciate your help. 
Cheers
Sharon
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