Ocean Color Forum - Not logged in
I am beginner in Seadas software. I would like to know how to cut an image MODIS level 3 binned and also mapped. I had downloaded the global image MODIS_level 3, but, I would like to crop the hdf files to my area of study, because i have no space in my HD to save to keep the overall global image. How do I make it in Seadas? The process is the same for both binned as mapped to the image?
To extract a binned file, just run it through l3bin with the appropriate lat/lon area defined. We don't have an extraction tool for SMI files, but you can sort of do it several ways depending on what you're looking for. You could use the Projection function to output a mapped product for your area of interest. Or you could use the Output function to write the binary data out to an HDF file. Then you can append the navigation. Here is an example of some code that would do that:http://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?pid=11817;hl=append#pid11817
Thanks, first of all,
sorry for my ignorance with l3bin
So I read the menu "help" of l3bin in the input I need "Enter the input TextFiles containing input filenames is time-binning." Sorry but I do not understand. What would be the text file, because I have only one file A20052892005296.L3b_8D.main. I thought it would be the input file. I have to create a. Txt?
thanks a lot
Since l3bin is normally used to bin together multiple input files, the text file is used to list the input filenames, and the text file is used as the singular input to l3bin. Then l3bin reads in the text file and parses out the multiple(or could be single) input filenames for processing. So what you need to do is to edit a text file and simply enter the full pathname for A20052892005296.L3b_8D.main and use that text filename as the input filename to l3bin.
So, I created a .txt file containing the directory path that is located A20052892005296.L3b_8D.main image. However, came the following error message: WARNING "The following error was encountered: HDF_SD_START: Invalid HDF file or filename (/ home_nautilus/thiala/A20052892005296.L3b_8D.main).
In this way it is binned the file, where I'm missing?
Make sure you haven't made an error in specifying the path and filename (e.g. there should be no space between "/" and "home_nautilus"). Try executing this command at the Unix prompt:
ls -l /home_nautilus/thiala/A20052892005296.L3b_8D.main
Is the file found?
Hi Mike, i wrote the command ls -l /home_nautilus/thiala/A20052892005296.L3b_8D.main,
and the console found the file: -rw-r--r-- 1 thiala Domain Users 831324563 Mai 13 15:32 /home_nautilus/thiala/A20052892005296.L3b_8D.main
Do you know where I'm missing?
The file size is right so I'm guessing the file itself is probably not corrupt. So I think there is a problem with your text file. I'd like to see the exact text in the file. So can you execute the command "cat file.txt" where you replace file.txt with the actual name of your text file, and then copy the result of the command and paste it in your reply.
Also, to create a new text file that works you should just be able to execute:
echo "/home_nautilus/thiala/A20052892005296.L3b_8D.main" >file.txt
Our binned files come in basically two forms. There is one form that uses what we've termed master/subordinate which splits up the different products(chlor_a, nLw, etc.) into separate "subordinate files". Your filename has a ".main" suffix, which tells me that you have the "master" file, but you probably don't have any of the "subordinate" product files that go along with it. I'm guessing that you may be getting the error because there are no subordinate files available. I could be wrong because I haven't tried it yet. So my question for you is do you have any "subordinate" files to go along with the "master" .main file? If not, you need to download them, because the master file will do you no good by itself.
I was wrong about that, I see now that the web site is offering ".main" files that are not in the master/subordinate form(which is an old format). Your 8-day file looks like it is the right size uncompressed so it has everything you need. As Mike suggests, let's see what your text file looks like when cat'ed.
Mark, when I did the download the only file that was available was ."main". No subject had a separate file. Why he is so big. And this is one of the reasons that I want to extract my area of study and select only the variable nlW 551 with the program l3bin.
I think I discovered the problem, the title / name that I gave to the file .txt was: A20052892005296.L3b_8D.main.txt , i renamed it to a shorter name, and work fine.
thanks for everything!
There is not available at the ftp site (ftp://oceans.gsfc.nasa.gov/MODISA/Binned/8Day/
) the master / subordinate which splits up the nLw551 or chlor_a products as you said, the products available are this: "CLCT; NSST; SST; SST4". Correct or am I looking in the wrong site?
You are correct. Disregard that as a possibility.
Yes, you can crop L3 images to focus on your areas of interest
using SeaDAS in either interactive or command mode.
(1) interactive: as Mark described above.
(2) command mode: please see below as reference. This script first
loads the image with a selected region then output as a mapped file.
f1 = 'A20090322009059.L3b_MO.main'
limit = [20,-95,50,-65]
load, f1, prod_name=['chlor_a'], xsize=900, ysize=600, limit=limit
display, BAND_NO=1, FBUF=1, stype='log', smin=0.01, smax=64
landmask, fbuf=1, color=6
grid, fbuf=1, latdel=5, londel=5,grdcol=6
coast, fbuf=1, color=7
outfile= f1 + '.map'
out, /data, band=1, outfile, ftype='mapped'