On Jul 5, 10:32 pm, bulrushmo...@gmail.com wrote:
> On Jul 5, 2:45 pm, bulrushmo...@gmail.com wrote:
>
>
>
>
>
>> On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote:
>
>>> On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote:
>
>>>> On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote:
>
>>>> > On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote:
>
>>>> > > Hi
>
>>>> > > I am extremely new to IDL (2 weeks!) and have previously only used
>>>> > > envi on a small scale.
>
>>>> > > I want to read one SD dataset from from a each of a huge number of
>>>> > > MODIS files and having looked at IDL and envi batch routines can't
>>>> > > decide which is the best way. Bear in mind my limited knowledge and a
>>>> > > very short timeframe.... Should I write an envi batch programme and
>>>> > > create a big (3000bands +) envi file or should I put straight into the
>>>> > > an IDL array. I need to get a mean value (one image or array) and
>>>> > > even if it is easier in envi batch mode, would the routine
>>>> > > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing
>>>> > > values???
>
>>>> > > Looking at IDL I have managed to open HDF file from command line, read
>>>> > > in appropriate data set to an array but how then could I build 3D
>>>> > > array from absolutely loads of 2D arrays.
>
>>>> > > Big questions I know - I am desperate to do this in a short time.
>
>>>> > > Any help on any aspect much appreciated.
>
>>>> > > K
>
>>>> > Tell me more about how many bands you have in HDF file and how many
>>>> > bands you want to read into IDL?- Hide quoted text -
>
>>>> > - Show quoted text -
>
>>>> Well I am going to be using around 3-4000 MODIS HDF files but I only
>>>> want one band (the first) from each i.e. the Land Surface
>>>> Temperature. Since my last post I have thought about creating a huge
>>>> multiband file in ENVI and then exporting as a variable to IDL (if the
>>>> ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with
>>>> missing values very well, I need them to not be counted as opposed to
>>>> counting as zero). However that means extracting the SD dataset from
>>>> all of the HDF files, converting them to ENVI standard files to build
>>>> multi-band image. I hope the data values are not corrupted by being
>>>> converted to ENVI standard. Also I could create an image stack in
>>>> iIMAGE or mess about with iDataManager in some way but they do not
>>>> seem to like reading ENVI standard files and keep asking me to fill in
>>>> binary information - will the data values still be OK?
>
>>>> Thanks
>
>>>> Kathryn- Hide quoted text -
>
>>>> - Show quoted text -
>
>>> The simplest way to do it:
>>> I am assuming you have IDL and ENVI, initiate batch mode by doing the
>>> following
>
>>> 1. define the file directory
>>> 2. read them into IDL using envi_open_data_file
>>> 3. get their mean by
>>> 4. print them into a txt file
>
>>> Try this code
>
>>> Pro Mean_HDF
>>> envi, /restore_base_save_files
>>> envi_batch_init, log_file='batch.txt'
>
>>> ; Open the file directory and searh for HDF files to read, then
>>> select the directory manually
>>> files=file_search(dialog_pickfile(/dir),'*.HDF', count=numFiles);
>>> or you can use files=file_search('D:\MODIS\*.hdf', count=numFiles)
>
>>> ; loop for the whole data set in the directory
>>> FOR K = 0, numFiles-1 do begin
>>> ; get the file name only without file directory for final
>>> output filename
>>> fname = file_basename(files[K])
>>> ;select input file directory to subset
>>> hdf_bands = 1 ; determines the HDF dataset bands to read
>
>>> ;start looping through opening bands from HDF
>>> for i = 0, hdf_bands -1 do begin
>>> envi_open_data_file, files[K], r_fid=fid, /hdf_sd,
>>> hdfsd_dataset=i, hdfsd_interleave=0
>
>>> ;query new file for ns, nl, dims;
>>> envi_file_query, fid, dims=dims, bnames=bnames, ns=ns,
>>> nl=nl, nb=nb
>>> pos=0
>
>>> ;get the mean of the data
>>> result = MEAN(fid)
>>> endfor
>>> ;if you want to export the results in screen do as
>>> print, results
>>> ;if you want to export them into a txt file
>
>>> OpenW, Lun, 'D:\test.txt', /get_lun
>>> str= fname
>>> printf,lun,str
>>> endFOR
>
>>> End- Hide quoted text -
>
>>> - Show quoted text -
>
>> I wonder if you are trying to get mean of each band you read or the
>> mean of thousands of bands over each pixel.
>> If you want to read just band you can get rid of the inside loop from
>> above code. Let me know I will help you figure out.- Hide quoted text -
>
>> - Show quoted text -
>
> If you are looking making a mean of all of the data bands you read,
> try the following
>
> Pro Mean_HDF
> envi, /restore_base_save_files
> envi_batch_init, log_file='batch.txt'
>
> ; Open the file directory and searh for HDF files to read, then
> select the directory manually
> files=file_search(dialog_pickfile(/dir),'*.HDF', count=numFiles);
>
> out_fid = lonarr(numFiles)
> ; loop for the whole data set in the directory
> FOR i = 0, numFiles-1 do begin
> ; get the file name only without file directory for final
> output filename
> fname = file_basename(files[i])
> ;select input file directory to subset
> hdf_bands = 1 ; determines the HDF dataset bands to read
>
> ;start looping through opening bands from HDF
> envi_open_data_file, files[i], r_fid=fid, /hdf_sd,
> hdfsd_dataset=1, hdfsd_interleave=0
> ;query new file for ns, nl, dims;
> envi_file_query, fid, dims=dims, bnames=bnames, ns=ns, nl=nl,
> nb=nb
> pos=0
>
> out_fid[i]=fid
> endFOR
> ; Set the keywords to process all the
> ; spectral data.
> ; Set the keyword COMPUTE_FLAG to
> ; compute the sum of the bands, the
> ; sum squared of the bands, the mean
> ; of the bands, and the standard
> ; deviation of the bands.
> out_pos = lonarr(numFiles)
> envi_file_query, fid, dims=dims, nb=nb
> out_name = 'Mean.img'
> compute_flag = [1,1,1,1,0,0,0,0]
> ;
> ; Call the processing routine to
> ; sum the data together.
> ;
> envi_doit, 'envi_sum_data_doit', $
> fid=out_fid, pos=out_pos, dims=dims, $
> out_name=out_name, compute_flag=compute_flag
> ;
> ; Exit ENVI
> ;
> envi_batch_exit
>
> End- Hide quoted text -
>
> - Show quoted text -
Hi
I am trying to get the mean of thousands of bands over each pixel.
Many thanks for the code I will give it a go tonight when I get some
time to play with it. My only worry is whether it will deal with the
missing values - I will let you know.
Many, many thanks
Kathryn
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