Plot data for a for specific x and y coordinates

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dylan price
dylan price on 18 Jun 2018
Answered: Afshin Aghayan on 8 Oct 2019
I have some data indicating precipitation at various coordinates in the world that I would like to plot. Each horizontal line is a combination of longitude (170...), lattitude (-72...) and precipitation (2...).
170.5 -72.5 2.11
171.5 -72.5 3.16
172.5 -72.5 2.69
173.5 -72.5 2.79
174.5 -72.5 2.41
I would like to plot the precipitation values for each set of xy coordinates as a chart with a colour scale varying for the precipitation amount. ie. x axis would be longitude, y axis lattitude and the chart would have multitude of different coloured points at their respective xy locations.
I have tried:
lat=dition;
lon=HDRAd;
data=al_ProcessingMap_Area_Averages_Removed;
lon=str2double(lon);
[lon,lat,data]=meshgrid(lon,lat,data);
surf(lon,lat,data)
which returns Error using repmat Maximum variable size allowed by the program is exceeded.
Error in meshgrid (line 77) xx = repmat(xx, ny, 1, nz);
Error in ecco (line 24) [lon,lat,data]=meshgrid(lon,lat,data);
The same thing with a truncated dateset yields this:
lat=dition;
lon=HDRAd;
data=al_ProcessingMap_Area_Averages_Removed;
lon=str2double(lon);
lon=lon(1:10)
lat=lat(1:10)
data=data(1:10)
[lon,lat,data]=meshgrid(lon,lat,data);
surf(lon,lat,data)
Error using matlab.graphics.chart.primitive.Surface/set Value must be a vector or 2D array of numeric type
Error in matlab.graphics.chart.internal.ctorHelper (line 6) set(obj, pvpairs{:});
Error in matlab.graphics.chart.primitive.Surface
Error in surf (line 150) hh = matlab.graphics.chart.primitive.Surface(allargs{:});
Error in ecco (line 12) surf(lon,lat,data)
I have also tried
map=pcolor(lon,lat,data)
to no avail. It feels like such a simple problem that I'm struggling with! Any help is much appreciated
  2 Comments
dylan price
dylan price on 18 Jun 2018
Thanks for the tip, I'll have a look at reshape. I've attached a .mat file

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Accepted Answer

Rik
Rik on 18 Jun 2018
You have holes in your data (i.e. not all grid positions have data). Therefore surf will not work. You can either choose to plot the data itself, or interpolate it. The code below shows how to do either.
lat=dition;
lon=str2double(HDRAd);
data=al_ProcessingMap_Area_Averages_Removed;
[lat_q,lon_q]=meshgrid(unique(lat),unique(lon));
F = scatteredInterpolant(lat,lon,data);
interpolated_data=F(lat_q,lon_q);
figure(1),clf(1)
%if you want to show the actual data itself as a scatterplot:
%plot3(lat,lon,data,'.'),hold on
surf(lat_q,lon_q,interpolated_data)
  1 Comment
dylan price
dylan price on 18 Jun 2018
Thank you! It would have taken me ages to figure this out

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More Answers (1)

Afshin Aghayan
Afshin Aghayan on 8 Oct 2019
you can use this code for displaying any data in the form of [x, y, f(x,y)] or data with coordinate

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