How do I extrapolate from my excel data to provide a smoother contour plot?

Hi There,

I am attempting to plot what is essentially a contour plot of temperature distribution within the waters of a scottish loch. I have data we retrieved through temperature / salinty / depth analysis of the loch and am looking to plot this as a general contour plot using the limit of the basic bathymetry data to show the see bed. The idea would be to use this script to plot additional salinity / o2 conc data in the same excel doc. I need to a) make the contour plot smoother b) have my bathymetry plot colored correctly (it's currently got the sea brown and the seabed white) and . c)get matlab to extrapolate (to the limit of the bathymetry plot) and plot contours where no data has been supplied. I am unable to attach the excel sheet with the raw data but I can provide my code...

If need be I can mail the raw data data to whomsoever requires it...

thanks in advance

Les

% Define Microsoft Excel Spreadsheet

filename = 'Contour Plots.xlsx';

% Define temperature data set

sheet_number = 2;

% 2 - Temp; 3 - Sal; 4 - O2 

xlrange_cont = 'B4:N144';

% Define Contour Plot

contour_plot = xlsread(filename,sheet_number,xlrange_cont);

% Plot Temp Contour Plot with colorbar and invert plot y axis for depth
subplot(1,1,1)
contourf (contour_plot);

set(gca,'YDir','reverse');

% Flips y axis for BOTH plots

colorbar;
hold on

% Bathymetry taken from event log (in m)

y = [39 5 52 60 74 13 146 140 88 43 25 1];

% Interpolate and smooth 'y' and define 'h' as area plot

x = 1:12;
subplot(1,1,1);
xx = 1:0.1:12;
yy = interp1(x,y,xx,'PHCIP');
h = area(xx,yy);

% Plot area and set colours and axes limits

area(h)
axis auto
xlim([1 12]);
ylim([1 150]);
set(h(1),'FaceColor',[0.5,0.25,0]); % wrong way round!!
hold off

% Add title and axis labels.

title('Temperature Distribution of Loch Etive(°C)')
ylabel('Depth (m)')
xlabel('Line of Bathymetry')