Wind and temperature divided into speed and temp

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Jenny 2013-9-24

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https://ww2.mathworks.cn/matlabcentral/answers/88061-wind-and-temperature-divided-into-speed-and-temp

评论： Jenny 2013-9-26

Is there a function to create a matrix with a count (i.e. number of occurrences) where wind speed goes from 0 m/s to 28 m/s in 1m/s intervals along the y axis (downwards i.e. 0 m/s at the top) and temperature goes from -15 deg C to 30 deg C in 5 deg C intervals, along the x-axis?

I have temperature time series data and wind speed time series data. I would like a matrix of counts that tells me how many times a combination of data occurred. For example, count how many time wind speed was 0 m/s and temp was between -15 and -10 deg C.

I can do this manually. I was wondering if there was a more elegant way of 'counting' the combinations and displaying the matrix.

Thank you, Jenny

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Jan 2013-9-24

Please post a meaningful example of the input in Matlab syntax and the wanted output. The description in text form is not clear enough.

Jenny 2013-9-26

My apologies. A more detailed request is posted below as a comment under Image Analyst's answer. There are also the two relevant attached files.

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Answer 1

Image Analyst 2013-9-24

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https://ww2.mathworks.cn/matlabcentral/answers/88061-wind-and-temperature-divided-into-speed-and-temp#answer_97657

编辑：Image Analyst 2013-9-24

在 MATLAB Online 中打开

logicalIndexes = windSpeed == 0 & (temp > -15 & temp < -10);
count = sum(logicalIndexes);
% Display the temps that have 0 wind speed
temp(logicalIndexes)

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Jenny 2013-9-26

Thank you for this answer. This is how to process the data 'manually' i.e.

Indexes_event1 = NewWindSpd <=1 & (NewTempData >= -15 & NewTempData < -10);

count_event1 = sum(Indexes_event1);

Indexes_event2 = NewWindSpd <=1 & (NewTempData >= -10 & NewTempData < -5);

count_event2 = sum(Indexes_event2);

Indexes_event3 = NewWindSpd <=1 & (NewTempData >= -5 & NewTempData < 0);

count_event3 = sum(Indexes_event3);

Which is repeated 9 times for the temperature groups and then 14 times again for the different wind groups.

I am trying to put this into a loop so that I have a more 'elegant' code, rather than almost 300 lines of code.

The TempData groups are: -15 to -10; -10 to -5; -5 to 0; 0 to 5; 5 to 10; 10 to 15; 15 to 20; 20 to 25; 25 to 30.

The WindSpd groups are: <1; 1 to 3; 3 to 5; 5 to 7; 7 to 9; 9 to 11; 11 to 13; 13 to 15; 15 to 17; 17 to 19; 19 to 21; 21 to 23; 23 to 25; >25.

Thanks for your help, Jenny

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Answer 2

Youssef Khmou 2013-9-24

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https://ww2.mathworks.cn/matlabcentral/answers/88061-wind-and-temperature-divided-into-speed-and-temp#answer_97661

编辑：Youssef Khmou 2013-9-24

在 MATLAB Online 中打开

Jenny, try this version ,

 wind=round(20*rand(20,1)); % arbitrary  wind time series .
temp=round(10*randn(30,1)); %arbitrary temperature time series .
W0=5; % your critical value of wind speed
temp1=5;  % bound1
temp2=15;  % bound 2 , critical values of temperature
e=1e-2;     %  Tolerance of the logical == operation 
% Replace wind and temp with your input
M=length(wind);  
N=length(temp);   
 I=zeros(M,N);     %  your counting matrix 
 for x=1:M
    for y=1:N
        if (abs(wind(x)-W0)<=e) && (temp(y)>=temp1 && temp(y)<=temp2)
            I(x,y)=1;
        end
    end
 end
 figure, surface(I);
 title(' detection of specific values ');
 sum(I(:))           %  number of occurence