How to recenter spatial data?

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JMSE
JMSE il 2 Nov 2021
Commentato: JMSE il 11 Nov 2021
I want to recenter spatial data from a grid of -180 to 180 lon to a grid of 0 - 360 lon. Using the command wrapTo360 leads to the issue below (see 2nd figure - you can see that the data > 180 shows an error). How can I reshape the rain/precipitation data accordingly so that the data is shifted correctly?
Help is very much appreciated.
dlat = load('latitude.mat');
lat = dlat.lat;
dlon = load('longitude.mat');
lon = dlon.lon;
dprec = load('rain.mat');
prec = dprec.prec;
lonW=wrapTo360(lon);
pcolor(lon,lat,prec);shading flat
pcolor(lonW,lat,prec);shading flat

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Konrad
Konrad il 2 Nov 2021
hi,
maybe I didn't get it, but why not just add 180?
lonW = lon + 180;
  3 Commenti
Konrad
Konrad il 2 Nov 2021
Modificato: Konrad il 2 Nov 2021
I'm still not sure what you aim to achieve. To you want to preserve the order of your x-data (longitudes)? Then
pcolor(lon+180,lat,prec);shading flat
will give you longitudes from 0 to 360 on the x axis; everything else looks exactly like in your first plot.
In contrast, wrapTo360() changes e.g. -1 to 359, -180 to 180. So basically, the left half of your plot is moved to the right. pcolor() seems to expect sorted values, so you would have to do:
[lonW,idx] = sort(wrapTo360(lon));
precW = prec(:,idx);
figure;pcolor(lonW,lat,precW);shading flat;
Best, Konrad
JMSE
JMSE il 11 Nov 2021
Many thanks, it helped a lot.

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