Figure is not properly overlapped on shape file, little shifted.

When I plot the output and overlay it on shape file, it comes little shifted.

Any suggestion would help me.

[Walter Roberson]

Plot the output of what, and do what to overlay it on the shape file?

[Jitesh Dadich]

I have India's Shape file and temperature parameter for this.

After plotting the temprature, when I try to view Shape file behind the temperature comes little shifted to left side. (i.e. it is not overlaying properly or something else is there?)

[Walter Roberson]

Please post your code.

[Jitesh Dadich]

Here it is :

S = shaperead('india_state.shp') ;
n = length(S);
x = zeros(n,1) ; 
y =zeros(n,1) ;
a=pcolor(lon,lat,Temp);
%Temp is temperature 
title('Tempeature')
xlabel('Longitude')
ylabel('Latitude')
colorbar
shading flat;
hold on
for i = 1:n
   x = S(i).X ; y = S(i).Y ;
   plot(x,y,'k')
end

[Walter Roberson]

pcolor() uses surf() underneath it. Each face is derived by interpolating the four corner vertices, so the number of faces shown is one less in x and y direction than the number of matrix entries. This can result in a shift relative to plotting the same coordinates due to differences in interpretation of what the coordinates mean. For pcolor, coordinates are vertices, but the what the user sees as color is faces between the vertices.

If there is no significant curvature in what you are drawing, you could consider using image() or imshow(), which accept XData and YData coordiantes that relate to the lower left and upper right corners. The coordinates are considered to be coordinates of the center of pixels.. but only uniform rectangular grids are possible image() or imshow()

Your code does not show where you are getting lon or lat or Temp from, so it is not clear that they relate to anything you read from S.

Answer 1

[Jitesh Dadich]

Thanks for your reply dear Walter Roberson.

I have attached a mat file of lat, lon and temp.

please tell me what to do?