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Problem with ENVI_CONVERT_File_COORDINATES [message #58833]

Sun, 24 February 2008 08:14

Wasit.Weather
Messages: 62
Registered: February 2008

Member

Hi,
I am having trouble to retrive a pixel value by geographic long lats.
Following is the code. two values obtained by sample/line coordinate
and geographic long lats are different. What is wrong with my code?
Thanks

;======================================================
;Open a file using envi batch

envi_open_file, fNameInput, r_fid=fid
if (fid eq -1) then begin
envi_batch_exit
return
endif
;
; Open the file to read in array
OpenR, Lun, fNameInput,/Get_Lun

; Setup the values for the keywords

envi_file_query, fid, ns=ns, nl=nl, nb=nb, data_type=data_type,$
interleave=interleave, dims=dims

Image=Make_Array(ns,nl,nb); create an array to get the values of the
image
readu, lun, Image; read the image pixel values into the array
Free_Lun, Lun

;print a pixel value by sample and rows
print, image[1040, 404, *] ;this prints pixel values for 6 bands
; this fine, correct

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Retrieve a pixel value by geographic long lats
;get coordinates for image and convert to lat/lon
xcoord=116.521
ycoord= 40.1455

;change from lat/long coordinates to pixel values

ENVI_CONVERT_File_COORDINATES, fid, xF, yF,xcoord, ycoord
for nb=0, nb-1 do begin ;read multi band data
data = ENVI_GET_DATA(fid=fid, dims=dims, pos=nb); pos is the
name of the band, 0=1st band, 5=6th band
output=data[xcoord, ycoord,*]
print, output; this prints pixel values for 6 bands
endfor
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;

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[Message index]

		Problem with ENVI_CONVERT_File_COORDINATES By: Wasit.Weather on Sun, 24 February 2008 08:14
		Re: Problem with ENVI_CONVERT_File_COORDINATES By: Jean H. on Tue, 26 February 2008 08:37
		Re: Problem with ENVI_CONVERT_File_COORDINATES By: Chris Jengo on Tue, 26 February 2008 07:21
		Re: Problem with ENVI_CONVERT_File_COORDINATES By: Wasit.Weather on Tue, 26 February 2008 17:04
		Re: Problem with ENVI_CONVERT_File_COORDINATES By: wita on Tue, 26 February 2008 00:18

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