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Re: envi_get_data [message #58273 is a reply to message #58173] Fri, 25 January 2008 06:03 Go to previous messageGo to previous message
lbusett@yahoo.it is currently offline  lbusett@yahoo.it
Messages: 30
Registered: February 2006
Member
Hi,

I don't know if it will solve all your problems, but I believe that
you should replace the instruction:

> image2=fltarr((nb,nl,ns)

with:

image2 = fltarr (nb, ns, nl)

because ENVI_GET_DATA returns an array in samples by lines order (see
the help). (Obviously, if you have a square image nothing will change)

You can also remove the instruction

> image=fltarr((nb,nl,ns)

since the "image" variable is overwritten by the "envi_get_data"
instruction.

Hope this helps,

Lorenzo

On 23 Gen, 22:57, yychon...@gmail.com wrote:
> Thank you Jean. I did correct the error you pointed out, and I found
> something werid for the output image. I used a 2bands input file and
> the output image seems twist and even does not have the correct
> boundary shape, and the data was wrong.
>
> Then I tested it with a one band input image, when I tried to multiply
> the input image by a constant to get a new image(my output) it did not
> work (it did not get the image that supposed to). If I just add the
> input image with a small number, it works fine. But if I add the image
> with a large number, like 35000(the min. data on the input image is
> -32768), then it went wrong again.
>
> I thought it might be due to the format of the image, then I changed
> fltarr to dblarr, it still wont give the right output image.
>
> Many thanks.
>
> Now my code looks like this:
>
> pro cal
> envi, /restore_base_save_files
> envi_init, /batch_mode
> envi_open_file,'F:\testinput.img',r_fid=fid
> if (fid eq -1) then return
> envi_file_query, fid, ns=ns, nl=nl, nb=nb, data_type=data_type
> map_info = envi_get_map_info(fid = fid)
> dims = [-1L, 0, ns - 1, 0, nl - 1]
> pos=lindgen(nb)
> image=fltarr((nb,nl,ns)
> image2=fltarr((nb,nl,ns)
> For i=0, nb-1 Do Begin
> image = envi_get_data (fid=fid,dims=dims,pos=i)
> image2[i,*,*]=image
> Endfor
> ENVI_WRITE_ENVI_FILE,image2,data_type=data_type,nb=nb,nl=nl, ns=ns,map_info
> = map_info, $
> out_name='F:\testoutput.img'
> END
>
> On Jan 21, 3:00 pm, Jean H <jghas...@DELTHIS.ucalgary.ANDTHIS.ca>
> wrote:
>
>>> envi_file_query, fid, ns=ns, nl=nl, nb=nb, pos=pos ,dims=dims
>
>> ... in the help file, there is no POS keyword in this function... so
>> later on, when you try to use it, pos is undefined.
>
>> Jean

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