On 20 Aug., 15:16, Conor <cmanc...@gmail.com> wrote:
> On Aug 20, 4:31 am, britta....@gmail.com wrote:
>
>
>
>> On 20 Aug., 09:23, britta....@gmail.com wrote:
>
>>> On 20 Aug., 02:41, "mgal...@gmail.com" <mgal...@gmail.com> wrote:
>
>>>> On Aug 19, 4:53 am, b...@uni-mainz.de wrote:
>
>>>> > Hello,
>
>>>> > i'm sorry to post a new message, but i did not find the answer to my
>>>> > question, when i searched for it (or i did not use the fitting words
>>>> > for the search).
>
>>>> > I try to read the values of a file with three columns and 2072758 rows
>>>> > (the file was created from a bmp-picture by the routine read_bmp).
>
>>>> > My code is as follows:
>
>>>> > file='E:\Dissertation\mz_cam\spectral_calib\dat-files
>>>> > \070807\run24\070807_24_0013.dat'
>
>>>> > n_pixel= 2072758
>>>> > n_channels=3
>
>>>> > dummy_ein=fltarr(n_channels)
>>>> > dummy = ''
>
>>>> > r=fltarr(n_pixel)
>>>> > g=fltarr(n_pixel)
>>>> > nir=fltarr(n_pixel)
>
>>>> > close, 1
>>>> > openr,1, file
>
>>>> > for i=0, n_pixel-1 do begin
>>>> > readf, 1, dummy_ein
>>>> > g(i)=dummy_ein(0)
>>>> > r(i)=dummy_ein(1)
>>>> > nir(i)=dummy_ein(2)
>>>> > endfor
>
>>>> > end
>
>>>> > Could the problem be related to the array length? I mean that there
>>>> > are too many values for an array? I checked the number of values
>>>> > several times, so i am quite sure that the number for n_pixel is
>>>> > correct.
>
>>>> To keep the loop, you definitely need the "L", that should fix the
>>>> "loop expression too large for loop variable type." error.
>
>>>> You didn't mention what the original problem was though. You did
>>>> mention later that there was an "end of file error." So I would make
>>>> sure there really are n_pixel number of rows in the data file. (Use
>>>> "nLines = file_lines(file)" to find out.)
>
>>>> By the way, you can do this without a loop:
>
>>>> file = 'E:\Dissertation\mz_cam\spectral_calib\dat-files
>>>> \070807\run24\070807_24_0013.dat'
>
>>>> n_pixel = 2072758
>>>> n_channels =3
>
>>>> data = fltarr(n_channels, n_pixel)
>
>>>> openr, lun, file, /get_lun
>>>> readf, lun, data
>>>> free_lun, lun
>
>>>> ; if you need the data in separate arrays
>>>> g = data[0, *]
>>>> r = data[1, *]
>>>> nir = data[2, *]
>
>>>> Mike
>>>> --www.michaelgalloy.com
>
>>> Hello,
>
>>> oh yes, i forgot in the original post to mention my problem. Sorry.
>>> I'll try to fix my problem with your suggestions.
>
>>> Thank you,
>
>>> Britta
>
>> Hello again,
>
>> i tried your suggestions, but i still get the "end of file-error".
>> Even if i tried the suggested code without the loop. Do you have any
>> idea what could be further wrong? I checked the number of lines with
>> "nLines = file_lines(file)". The number is correct :-( .
>
>> Yours,
>> Britta
>
> Another possibility is that there are not exactly three columns in
> each line of text. Is there any missing data? Take the following
> (common) example:
>
> Contents of File:
> 1234 5678 9012
> 1234 9012
> 1234 5678 9012
>
> data = intarr(3,3)
> openr, lun, 'File', /get_lun
> readf, lun, data
> free_lun, lun
>
> In this case you will also get an EOF error. The reason is because
> IDL is trying to read 8 values into a 9-element array. By default,
> IDL's read operation seems to be a string-split operation. It splits
> up the line wherever it encounters spaces. So, when it reads the
> second line it splits it up and only finds two values. Since it needs
> three values in a row, it goes ahead and continues to the next line
> and reads the first value in that line. Now, IDL will be one element
> ahead of the game, and when it tries to read in another three values
> for the third row of your data element, it prematurely reaches the end
> of the file because there are only two actual data values remaining in
> the file. The solution in this case is to replace the blank spaces
> with junk data that is easily recognizable as "no data". For
> instance:
>
> New Contents of File:
> 1234 5678 9012
> 1234 -999 9012
> 1234 5678 9012
>
> Then, IDL will no longer have an EOF error, and you simply select out
> any data less than -900
Hello,
first, thank you all for your help.
The missing data was some kind of correct guess. Yesterday a colleague
of mine suggested to try "data = read_ascii(file)& data=data.(0)". It
worked but the resulting array had a different length. The routine
read_bmp (the file was created with this routine) creates a blank line
after each whole image line (image resolution 1920x1079 -> blank line
after 1920 values), which i didn't detect before (because i was too
lazy to scroll through 2072758 lines :-/ ). And this created the End
of File error. The read_ascii has no problems skipping these blank
lines.
Yours,
Britta
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