| Re: reading envi file in IDL [message #55524 is a reply to message #55523] |
Thu, 23 August 2007 10:55   |
robinson.inj
Messages: 32
Registered: August 2007
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Member |
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On Aug 23, 10:48 am, "Jeff N." <jnett...@utk.edu> wrote:
> On Aug 23, 12:09 pm, robinson....@gmail.com wrote:
>
>
>
>> Dear All,
>> I created a file using ENVI and its header file is below. Does
>> somebody could show me how to read that file in IDL?
>> In advance thank you very much
>> Robinson Juarez
>
>> =======================================
>> ENVI
>> description = {
>> File Resize Result, x resize factor: 1.000000, y resize factor:
>> 1.000000.
>> [Wed Aug 22 10:02:17 2007]}
>> samples = 400
>> lines = 400
>> bands = 5
>> header offset = 0
>> file compression = 1
>> file type = ENVI Standard
>> data type = 4
>> interleave = bsq
>> sensor type = Unknown
>> byte order = 0
>> x start = 1323
>> y start = 714
>> map info = {UTM, 1.000, 1.000, 694231.500, 9759973.000, 2.8500000000e
>> +001, 2.8500000000e+001, 20, South, WGS-84, units=Meters}
>> wavelength units = Unknown
>> band names = {
>> Resize (Unmix (amazonas_p231r062_etm_071001_a5) EM:GV (X:4278 Y:
>> 1152):MAO20071001_test1.em),
>> Resize (Unmix (amazonas_p231r062_etm_071001_a5) EM:NPV (X:6152 Y:
>> 928):MAO20071001_test1.em),
>> Resize (Unmix (amazonas_p231r062_etm_071001_a5) EM:SOIL (X:5959 Y:
>> 4199):MAO20071001_test1.em),
>> Resize (Unmix (amazonas_p231r062_etm_071001_a5) EM:SHADE (X:2359 Y:
>> 2415):MAO20071001_test1.em),
>> Resize (RMS Error:MAO20071001_test1.em)}
>> ============================================================ ======
>
> Well, if you look at the ENVI help files you'll see what all these
> header values mean. The dimensions of the image are the samples,
> lines, and bands. The bsq interleave tells you that the dimensions
> are (400,400,5). The data type of 4 means float data (i'm pretty
> sure, double check this). Header offset = 0 means the binary file is
> all data, no header bytes.
>
> So, in this case it would normally boil down to a simple readu:
>
> img = fltarr(400,400,5)
> openr, lun, image_file_name, /get_lun
> readu, lun, img
> free_lun, lun
>
> I say it *would* boil down to the code above b/c i've never seen the
> "file compression = 1" line in an envi header. If the file is
> compressed you're going to have to deal with the compression, however
> that was done.
>
> Also check to make sure the byte order matches your machine (if you
> created the image file on the same machine you're reading it with, it
> shouldn't be an issue).
>
> Hope that helps,
> Jeff
Jeff, I tried that before post my ad., but did not work.
Robinson
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