How to read .txt separate by - and in dms format

Question

Thomas prn 2021-4-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/791069-how-to-read-txt-separate-by-and-in-dms-format

评论： dpb 2021-4-3

采纳的回答： dpb

NONNA100_4600N07100W.txt

在 MATLAB Online 中打开

Hello,

I like to convert a .txt file in longitude and latitude data (DMS) to UTM (especially MTM 7 nad 83)

I have found the following command to do this : https://www.mathworks.com/help/map/ref/geodetic2ecef.html or https://www.mathworks.com/matlabcentral/fileexchange/9696-geodetic-transformations

But I don't succed in reading the .txt file and the format is a bit tricky.

I have this type of file :

"Lat (DMS)" "Long (DMS)" "Depth (m)"
46-34-50.894N 071-59-59.280W 0.30000
46-34-53.066N 071-59-56.016W 0.60000
46-34-55.928N 071-59-59.853W 1.80000
46-34-54.546N 071-59-58.198W 1.20000
...

And I would like to have a matrix with 7 columns like that :

34 50.894 071 59 59.280 0.30000
34 53.066 071 59 56.016 0.60000
34 55.928 071 59 59.853 1.80000
34 54.546 071 59 58.198 1.20000
...

I dont know how to import the file and separate the number because the deliminater is '-' and '[space]' and I also want to get rip of N and W...

Do you know how to do this ?

Thanks

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Answer 1

dpb 2021-4-2

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https://ww2.mathworks.cn/matlabcentral/answers/791069-how-to-read-txt-separate-by-and-in-dms-format#answer_665489

在 MATLAB Online 中打开

>> fmt='%f-%f-%fN %f-%f-%fW %f';
>> data=cell2mat(textscan(fid,fmt,'CollectOutput',1,'HeaderLines',1))
data =
         46.00         34.00         50.89         71.00         59.00         59.28          0.30
         46.00         34.00         53.07         71.00         59.00         56.02          0.60
         46.00         34.00         55.93         71.00         59.00         59.85          1.80
         46.00         34.00         54.55         71.00         59.00         58.20          1.20
>> fid=fclose(fid);

NB: Above works only if the coordinates are all N and W; otherwise one will have to either skip a character in the format scan string and trust can figure out what is what from numeric values or return it as string variable.

But, there's nothing really magic, just write an appropriate format string for the file format.

Or, you could read the whole thing in as a cellstr() array and then split() on the delimiters if wanted to do that way.

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Thomas prn 2021-4-2

编辑：Thomas prn 2021-4-2

Ok thank you. Yeah it's not a big deal but I don't realy understand the symbole in the fmt command so I was blocked.

What di you put in your fid file please ?

dpb 2021-4-2

在 MATLAB Online 中打开

That's just the file handle for textscan...

fid=fopen('yourfilename.txt','r');

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Answer 2

Cris LaPierre 2021-4-2

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/791069-how-to-read-txt-separate-by-and-in-dms-format#answer_665684

编辑：Cris LaPierre 2021-4-2

在 MATLAB Online 中打开

NONNA100_4600N07100W.txt

I was trying to avoid using a formatspec, but I can't think of a good way. Here's how I would probably do it. The result is a table. See this page on how to access data in a table. How you access it determines if the extracted values are in a table or an array.

data = readtable("NONNA100_4600N07100W.txt",'HeaderLines',1,"ReadVariableNames",false,...
    'Format','%f-%f-%f%*c %f-%f-%f%*c %f')
data = 20896×7 table
Var1Var2Var3Var4Var5Var6Var7________________________________

    50      3.517     71       0      0.566    -1.4
    50      5.945     71       0      0.239    -0.2
    50      4.438     70      59     55.439    -2.3
    50      6.363     70      59      50.55    -0.5
    50      6.851     70      59     45.749    -0.7
    50      9.081     70      59     59.927    -0.4
    50      9.577     70      59     55.418    -0.2
    50      9.191     70      59     50.348    -0.7
    50      9.429     70      59     45.541    -0.8
    50       8.59     70      59     41.131    -0.3
    50     10.014     70      59     36.262    -1.1
    50     13.191     71       0      0.016    -0.3
    50     12.418     70      59     55.431    -0.8
    50     12.593     70      59      50.06    -1.6
    50     12.593     70      59     45.648    -1.2
    50     11.827     70      59     41.264    -0.8