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Re: trying to export pixel data from .dat files, based on coordinate loc [message #71616]

Fri, 09 July 2010 15:40

Maxwell Peck
Messages: 61
Registered: February 2010

Member

On Jul 10, 2:53 am, Snow53 <jennifer_wa...@hotmail.com> wrote:
> Hi, I'm new to IDL so this might sound very easy to some. Sorry!
> I have 200+ .dat files in one folder, and one associated .hdr file
> that will work for all of them.
> I would like to loop through all the files and extract pixel value
> information based on an input coordinate location (lat, long) for each
> file, and then export all this information into a .txt file or
> similar.
>
> I've been trying to follow other posts that have done similar, but I
> seem to be writing this out wrong as my code isn't compiling correctly
> (I seem to have problems on lines 9 & 14, see below). I don't know
> enough about IDL rules to know the correct way to do this.
>
> If anyone could advise, I'd be so grateful! Cheers!
>
> Name: extractdata.pro
> ;
> ; Goal: Extract pixel data based on input coordinate location for each
> file (.dat)
> ; within a specified folder location. Export this data to a .txt file.
>
> pro extractdata
> ;define path
> filepath='X:\MERRA\HDF_Output_Lena\'
> ;open envi files within given folder
> file_array=file_search[filepath, '*.dat', count['*.dat']= num_file]
> for i=0, num_file-1 do begin
>
> file=file_array[i]
> print, num_file
>
> ;read ENVI binary file
> read_ENVI_image (file, headerfile= filepath, '*.hdr')
> ;extract pixel information based on lat long coordinates
> b=ENVI_CONVERT_FILE_COORDINATES [106.002, 83.0]
> v=b
> print, v
>
> ;open text file to write data to
> OPENU, U, 'pixel_value.txt', /get_lun, /append
> ;write data
> printf, U, v
> ;close LUN
> close, U
>
> endfor
>
> end

Use ENVI_OPEN_FILE. Use the FID from this command in the
ENVI_CONVERT_FILE_COORDINATES. ENVI_CONVERT_FILE_COORDINATES is a
procedure, you need to specify the output variables in the command.

This is relatively straightforward and can almost be copy and pasted
directly from the ENVI help..

Max

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[Message index]

		Re: trying to export pixel data from .dat files, based on coordinate loc By: Maxwell Peck on Fri, 09 July 2010 15:40
		Re: trying to export pixel data from .dat files, based on coordinate loc By: Maxwell Peck on Mon, 12 July 2010 14:51
		Re: trying to export pixel data from .dat files, based on coordinate loc By: Maxwell Peck on Mon, 12 July 2010 14:39
		Re: trying to export pixel data from .dat files, based on coordinate loc By: Snow53 on Mon, 12 July 2010 14:29
		Re: trying to export pixel data from .dat files, based on coordinate loc By: Maxwell Peck on Mon, 12 July 2010 14:12
		RE: trying to export pixel data from .dat files, based on coordinate loc By: Snow53 on Mon, 12 July 2010 13:37

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