Read data from binary file

Hi all.

I am having trouble with reading a dataset in binary format. I have tried with the 'fread' and 'fopen' function, but can't seem to get what I want.

The binary file should be a dataset for some wind velocity. When using the 'fread' and 'fopen' I just get a lot of integers, that doesn't look like the typical development in wind velocity fluctuations:

%%%

data1 = fread(fopen('data.bin','r'));

plot(data1(1:1000))

%%%

I also tried to separate the data into more columns, which also don't look like the solution to my problem:

%%%

noc = 8; %Number of columns

data = reshape(data1,noc,length(data1)/noc)';

for i = 1:noc

subplot(noc,1,i),plot((0:1:length(data)-1),data(:,i)),xlim([0,1000])

end

%%%

Do I need to convert this to something else, or can anyone give me a hint in the right direction? It might be my lack of knowledge for binary files.

Best regards

Answer 1

[Mehmed Saad]

By default, fread reads a file 1 byte at a time, interprets each byte as an 8-bit unsigned integer (uint8), and returns a double array.

So you need to convert it to binary array.

To convert a number to binary array de2bi is used in matlab

For example

de2bi(1,8)
ans =

     1     0     0     0     0     0     0     0

it reutrns an 8 bit binary array (as i specified it in 2nd argument) and msb is on right.

Now if i have two numbers

de2bi([1 2],8)
ans =

     1     0     0     0     0     0     0     0
     0     1     0     0     0     0     0     0

Also if you want to read double from binary file you can directly use

fread(fileID,'double') 

For example

I write a double value 0.101 in binary file doubledata.bin

fileID = fopen('doubledata.bin','w');
fwrite(fileID,0.101,'double');
fclose(fileID)

Now i am reading it

fileID = fopen('doubledata.bin');
fread(fileID,'double')
ans =

    0.1010