Extract data from a matrix for each polygon in a shape file

I have a matrix (331X301) at 0.1 degree resolution data encompassing entire India and a shapefile with 2299 attributes(polygons). I generally extarct data for each attribute from the matrix raster in ArcGIS. Is there a way to extract the mean data(mean of all the 0.1 degree grids that fall in that attribute) for all the polygons of the shpfile in Matlab?

Link for shapefile: https://1drv.ms/f/s!Ajxh9oeoND9bhOcwrzoLfEqBUNUTOg

Link for data: https://1drv.ms/u/s!Ajxh9oeoND9bhOcva9i-ByW45YBwoA

Note: the data is 3 dimension-331x301x12.

Below is the code written to overlay the shapefile on the data.

However, the shapefile S has 2299 attributes, I could not extract value of z2 for each of these 2299 attributes

Reading the shapefile
S=shaperead('C:\shpfiles\india_adm3.shp');

%selecting the first month from the data of 321x321x12
z2= data(:,:,1)

%makking dummy coordinates for the data
x = linspace(67, 97, 301);
y = linspace(5, 38, 331);
[x,y] = meshgrid(x,y);
y=flipud(y);

%Clipping the data to the coastlines
isin = inpolygon(x,y,S.X,S.Y);
z2(~isin) = NaN;


figure('color','w');

mx=geoshow('landareas.shp', 'FaceColor', 'White');

%display the data
contourf(x,y,z2,'LineColor','none');

hold on

%display the shapefile
S1=shaperead('C:\shpfiles\india_adm3.shp','Attributes',{'BoundingBox'});
lon1 = [S1.X]';
lat1 = [S1.Y]';
plot(lon1,lat1,'Linewidth',2,'color',[0 0 0]);

Answer 1

[KSSV]

Read about inpolygon.

[Sourangsu Chowdhury]

Hi @KSSV, I tried using inpolygon ,

but the output S is a struct of 2299x1, so it returns an error

%Clipping the data to the coastlines
isin = inpolygon(x,y,S.X,S.Y);
z2(~isin) = NaN;

however, if I use a shapefile with no other inset polygons, this code works fine

[KSSV]

shapefile conains many polygons....you need to run a loop for each polygon.

isin = inpolygon(x,y,S(i).X,S(i).Y);

See to it that..you have closed polygon coordinates in hand.

[Sourangsu Chowdhury]

for i=1:2299;

isin = inpolygon(x,y,S(i).X,S(i).Y);
z2 = z;
z2(~isin) = NaN;
xf=nanmean(nanmean(z2,2),1);
cx(i)=xf
end;

ok, I was able to get the desired results, with the following @KSSV;

thank you so much,

just inquiring, is there a way to add facecolor to each of these polygons as per the values of cx and plot it?

[KSSV]

Read about patch

[Sourangsu Chowdhury]

as an extension to the previous code, I wrote

for ii = 1:numel(S)
  S(ii).cx = cx(ii); % add your data here
end

to add cx as a feature to the existing shapefile. I now need to display the shapefile with one distinct color (of a colormap like jet) for each polygon within the shapefile

[Sourangsu Chowdhury]

h = geoshow(S);
set(h.Children, {'CData'}, {S.cx}');
set(h.Children, 'Facecolor', 'flat');

I tried with the following code, but it returns an error,

Error using matlab.graphics.primitive.Patch/set

Value cell array handle dimension must match handle vector length.

[KSSV]

figure
hold on
for i = 1:N
  x = S(i).X ;
  y = S(i).Y ;
  patch(x,y,rand(1,3))
end