hi,

I am trying to map some data I have against chlorophyl a concentration maps obtained through the SeaWiFS satellite.
I downloaded the images from ftp://oceans.gsfc.nasa.gov/SeaWiFS/Mapped/Monthly/CHLO/2005 and I got files with a bz2 extension, which I can not open

I am trying to use these data in ArcGIS, could somebody help me?
(How can access the data?)

Thank you.
regrads,
Ana

ana,
as described in the help menu:
The Level 0 (MODIS only), 1, and 2 HDF files in our archive have been compressed with the bzip2 compression utility. This utility freely available. If your system does not have this utility, you may find it at: http://sources.redhat.com/bzip2/. For Windows users, a freely available utility, 7-Zip, can handle this format: http://www.7-zip.org/.  The bzip2 compression format is a lossless format similar to the ubiquitious gzip format, but with an improved compression ratio. The table below shows the compression ratio for an example file:

Compression Format  Size (megabytes)  Ratio
uncompressed  206  1
UNIX compress (.Z)  86  0.42
gzip (.gz)  77  0.37
bzip2 (.bz2)  54  0.26

as for using the data in arcgis,  take a look at the oceancolor forum section on non-seadas packages at:
http://oceancolor.gsfc.nasa.gov/forum/oceancolor/board_show.pl?bid=18

regards,
gene

Dear Gene (and Norman),

Thank you very much for your reply.

I have 7z already installed in my computer and I was using it to unzip the downloaded files.
After extracting the data from the bz2 file, I still get a file that I can not open with any program

Example:
chlorophyll image - seasonal S19972641997354.L3m_SNAU_CHLO_9.bz2
After extracting with 7z: S19972641997354.L3m_SNAU_CHLO_9
Which ends up having the file type: L3M_SNAU_CHLO_9  that my computer do not recognize, so, still I can not use the data

I also downloaded the bzip2 you suggested, but apparently I have to run it on Dos. I could not understand how (I was going to the direction where I saved the .exe file:

>c:
>cd foldername

Inside the forlder I could not run the bz2.exe it on DOS - problem migth be, because I do not know which command to use to run exe files once I am inside the directory

Would this other program give another file type once the images are unzzipped? Or would I still have the same problem?

I wish there was a simpler and quicker way to understand how to get to the data ...
Initially I was using the pictures for chla concentration, opening them in ArcGIS, overlaying with my data, and everything looked perfect, untill I needed the chla values per pixel.
In the .png files I could only get RGB values per pixel... 
(So... If there was a table giving me the relation between RGB values and chla concentration, I would have my problem solved almost imediately.... but I guess that getting this conversion is the most difficult part (?))

Again, thank you very much for your time and attention.
I will be waiting for your comments.

With best regards,
Ana

Sorry, I forgot to mention that I trying to run Bz2 by writting the file name without the ".exe" at the end: bzip2-105-x86-win32

I was getting the following 2 lines (after pressing enter):

bzip2-105-x86-win32: I won't write compressed data to a terminal.
bzip2-105-x86-win32: For help, type: 'bzip2-105-x86-win32 --help'

and nothing happened

Again thank you,

Ana

Me again...

Sorry!

just to let you know that I found out how to use Bzip2, but the result I am getting is the same I got with 7z, i.e. file seems to be corrupted or damaged some how.

No extension appears after decompression and therefore I do not know how to access the information inside.

Sorry if I look a bit anxious... I need these data for performing the analysis I need to present in a conference and it is making me a bit nervous that I still couldn't access the data. But I will get there!

Again, thank you very much!
With best regards,
Ana

Hi Ana,

The level-3 mapped files that you are trying to read are in HDF4 format
after decompression with 7zip or bunzip2 even though their names do
not end in ".hdf".  See the file descriptions at:

http://oceancolor.gsfc.nasa.gov/DOCS/ocformats.html

You could always try renaming your files to end in ".hdf" to see
whether your software would recognize them any better that way.

You might also consider using the SeaDAS package which can
read the files as they come from our archive.

Norman

Thanks.

but...guess this takes us back to the email I sent you 1 week ago
re. Seadas not working in my computer - which was the reason why I was trying to solve the problem this way.

Will use your advice at that time, re. moving on to your non SEADAS forum...

(Anyway, now I have opened the unzipped files in ArcGIS and it recognizes them as hdf files. But still no chl values para pixel are displayed...
So guess this is actually taking me back to the very beginning - when I was using png files and got to the problem of having no chl values... seems like I am going in circles ... not good )

Thanks for your assistance.
Ana

Hi Ana, sorry you're running into so much trouble. There's a bit of a learning curve when you start dealing with HDF files, and we also do everything in a Unix environment so it's tough for us to support Windows users. You said:

> guess this takes us back to the email I sent you 1 week ago re. Seadas not working in my computer

We can't find any email from you so I'm not sure what problem you were having. Even though you are working in ArcGIS on Windows, I think a very good thing for you to do would be to install SeaDAS VA. This is a version of SeaDAS that will run on your Windows computer in a virtual Linux environment. I suggest this because if you do this you will be able to immediately load any of our data and display the chlorophyll data values very easily. So even if you will still need to work in ArcGIS, you will at least be able to learn about our data and make sure whatever you calculate in another software package matches what you see in SeaDAS. To install SeaDAS VA read all the information and then follow the steps carefully on this webpage:

   http://oceancolor.gsfc.nasa.gov/seadas/seadasva.html

And here's a possible first approach you could try that might make your life much easier:

1) Install SeaDAS VA on your Windows PC

2) Enable a shared data directory on your Windows hard disk as discussed here

3) Uncompress an SMI file, e.g. S20050012005031.L3m_MO_CHLO_9.bz2

4) Load this uncompressed SMI file into SeaDAS and display the chlorophyll product

5) In the SeaDAS display window select Functions->Output->Data->Binary

6) In the Output Setup window near the top, for "Type:", select "Image Display"

7) In the Output Setup window near the bottom, for "File Type:", select "TIFF/GEOTIFF"

8) Click "Go" to save a new GeoTIFF file

9) In Windows, try opening this GeoTIFF file with ArcGIS, and if all goes well you'll have you geolocated chlorophyll image!

Good luck, and let us know how it goes..

Dear Mike,

Thank you very much for your reply!
It seems, definitely to be the best approach

I have followed your steps and I can display the image in Seadas as well as creating the GeoTiff image that should be easily read by ArcGIS, as you suggest.

The only thing that I could not understand was were was this image saved?
I got the following message from seadas after doing your step 8:
"i: SDP_WR_DISPLAY: Wrote file S19972641997354.L3m_SNAU_CHLO_9_Chlorophyll_a_concentation.tif."

So I suppose the image was created, but I could not find it
I checked the seadas_shared folder created in c: drive, but it was not there.
Were does seadas save the images by default?

Thank you very much!
Ana

P.S. - Yesterday I have posted a comment in the non-seadas forum - I had just found the equation to transform pixel values into chla values. But the approach you suggested should definitely be better - 1st because it is easier, and 2nd because I can use it for checking my other calculations as well.

P.S.2 - The problem I was having with seadas was related to not finding the website - 1st test from your installation steps to check if the application was able to communicate with the network.
I am still having this problem, though now (text above) I used the shared folder, so did not need to use the website.
I suppose to download and treat all the images I need I should be downloading them directly into Seadas, as you explained in that other link you sent me.
Do you know how can I solve this? - I have firefox installed and running in windows (finding your website with no problems).
Or, how can I put the images I have already downloaded and unzipped in a seadas folder to save computing time in the process of creating the tif files?

P.S.3 - My display setting in windows are 1440 x 900 pixels, and I tried to change the linux settings as explained in the information steps:
-in one terminal window I wrote "Sudo sedres"
- it printed on the screen "[sudo] password for seadas:
- i tried to wrote "seadas" but it would not let me
So i could not change the settings. Could you please explain me how can I change from the  1280x1024 to 1440x900 pixels?

P.S.4 - Although everything seemed fine seeing the image in seadas, I still did not see any chlorophyll a information anywhere... How can I check the values in the green areas, for instance?

Again! Thanks! It seems that after this I will start seeing the light at the end of the tunnel

Hi

just to let you know that I could find the created .tif in seadas under:

file:///home/seadas

there is a folder called Desktop
and the file seems to be inside that folder (with 27355 kB)

When I double click on it to try to open it a window is prompt asking: "What should Firefox do with this file?"
with the following 2 options:
- open with (Browse)
- save file

Choosing the 1st one it goes to the seadas "Choose Helper Application", where I do not understand what to do - because it just lets me open other folders, instead of opening the image I firstly asked to be open (before pressing Browse)
Choosing the 2nd one a window called "Downloads" appear with the name of the image followed by its size and the words "- local file". With no options to choose - it seems to be only an informative window.
(I searched for file:///home/seadas/.local to check of the image went there, but I could not find it. the share folder seem to be inside this .local folder, but couldn't find the image there either )

So at any of these occasions I am actually seeing or saving the created file in my computer, it seems that everything is online (?) - but no path is specified to go and get the image.

How do I make the link here, from Seadas to the shared folder in windons, so I could be able to open the created image with ArcGIS?

Again,
Thank you for your help.

Regards,
Ana

Regarding your problem typing the password at the "sudo" prompt:

1. the system is designed to "hide" the characters you type, so you just enter "seadas" blindly and hit <Enter>

2.  We have the SeaDAS VM on four new PC's.  On 3 of the PC's there have been no problems, but on the 4th, the VM sometimes stops
accepting keyboard input.  The other PC's were all using the vendor's USB keyboards,  while the problem machine has been updated to
Ubuntu 9.04 and was using a PS2 to USB converter with a non-standard keybaord.  I just tried SeaDAS VM after switching to the standard
keyboard, and there was some problem entering the password in a popup box askign if I wanted to install add-ons for firefox.  I entered
the password and got "******" displayed, but when I hit enter the box just redisplayed with the "******".   The popup also had a button
(don't recall the text), which did accept the password.  

Regarding the question about where files are saved -- users here share in your confusion.  The virtual machine is just that -- a software
simulation of a whole PC, including a virtual disk, which Windows sees as one or more big files.   The "shared" folder can be used to transfer
data between windows and the virtual machine.   You will have to enable "Shared folders" in the VMware Player, and create the "C:\SeaDAS_shared"
directory in Windows.   To check that it is working, create a small test file in Windows, say "windows_file.text".  The in a SeaDAS VM terminal, type:
"ls ~/shared" and you should see a file listing that includes you test file.  Note that there is high overhead moving data between the VM
and the shared folder on your host (windows) disk, so you only use this when you have a file that you will want to use in Windows.

Concerning displaying the TIFF/GeoTIFF file you've created, few browsers support displaying TIFF formats, so that is probably why you're having problems when you double-click on it and the system defaults to trying to display it with firefox.  What you should be doing, if you want to see the TIFF file, is to display it in SeaDAS.  Just click on the Display button and load the file like you would any other image you wanted to display.

To move your TIFF file out from your virtual machine environment to your windows environment, you have to use the shared folder mechanism, as George and Mike have alluded to previously.  It's fairly simple.  As Mike suggested, go to this link for instructions on how to set up the shared folder:

http://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?tid=2923

We are going to have to look into the issue concerning files being created in the Desktop directory.  Normally, files are saved by default in the $SEADAS directory.  I agree that if they are showing up in the Desktop directory, that is confusing.  We'll look into it and fix that if we have it configured incorrectly.

Ana, one of your previous statements sounded like maybe you were having problems getting the virtual appliance to connect up with your PC's network.  Are you able to start firefox in the virtual appliance and get to an external website?

Mark

Ana, another thing to keep in mind is that the directory where you start SeaDAS will be the default directory where any images are saved. So to make things easy for you right now you could "Quit" the SeaDAS that automatically starts and then in an xterm change your directory (using the "cd" command) to your Windows shared directory where the SeaWiFS L3 file resides. Then start seadas by typing "seadas". Now if you save a GeoTIFF file it will be created in the Windows shared directory where you can access it from ArcGIS.

Hi!

Thank you very much for the effort!

It is very difficult for me to understand what you are trying to explain though, I am sorry.
I have never worked in a Linux environment before.

I can not change the directory - or better, probably I do not know how to do it.
As before, it does not seem to accept my password - at least nothing happens! It just lets me write what ever I want, without giving any answer.
I was trying to enter the VM using the "sudo setres" and "seadas" password and then use the Vm as if it was in "dos environemnt", to try and change the directory:
- C;
- dir,
- etc.
It did not work.

Also, if I try to open firefox in the VM, it does not work - it opens a window saying: Failed to connect. Firefox can't establish a connection to the server at ocean.gsfc.nasa.goc
(As I wrote before, in Windows firefox is working perfectly.)

Although I have created the tiff file I need, and can display it in VM, I still can not access the data and work with it

I am running out of time now, and I need to treat the data asap for that conference, so (and because the other method I found and described in your non-Seadas forum seems to be working) could you please make a comment on that method?

I would like to learn about seadas as well, so if you can find another way to explain me what migth be wrong, please let me know.

Again, thank you very much.
With best regards,
Ana

Hi to all (again)!

I think I finally found a possible reason for the problems I had with Seadas!
After having read more carefully WhiteG comments, I understood that I was not using Seadas as a software, but more as a window opened in Windows! I mean, I did not launch the program and then closed it properly!
It was a very silly mistake and I am sorry for that!
I rebooted the program, started it properly and after that I could enter the (blind) password with no problems and it gave me a list to change the screen resolution (which is perfect now! ).
I also used the command WhiteG suggested and I can see the files I have inside the seadas_shared folder

Answering Mark, re. if I can access an external website - if I use the Firefox launcher on the taskbar buttons, I get the error message I have explained above, but if I click help while trying to do an operation it opens your website!

Guess I am getting closer
(I did the analysis I needed already - using ArcGIS functions to transform the pixel values from hdf files into chla mg m-3, so I am a bit calmer now and willing to learn about seadas! )

Will keep on trying to get the tiff output from Seadas directly, but would like to ask if I can make operations in seadas as well (eg. estimate the range of chla values in each pixel for a range of images, lets say daily, for one year?) - Or maybe I should read something about seadas first, so I can get started... is there a tutorial online or so? (I saw that you have a webpage for Seadas with the main commands, is this it?)

Also, and repeating the steps indicated by Mike, I can create the Tiff image that it is still being saved under the desktop directory. Clicking on help, a small window opens saying:
- "(... ) to move into a subdirectory, click on its name in the directory list on the left. The patch can also be modified to view files from a different directory. The full name can also be typed in directly in the selection area. The list of files can be modified by typing in a filter."

So to transfer the tiff image created I tried to followed these steps, but I could not make it. What shall be typed in "filter"? Shall it be seadas_shared, in this case?

I also tried to type the comands used in DOS (to copy and paste a file in different folders) in one of the terminal windows:
cp /home/seadas/Desktop/s19972641997354.L3m.SNAU_CHLO_9_Chlorophyll_a_concentration.tiff mnt/hgfs/seadas_shared

Thank you so much for all your patience guys!
(And I am sorry for taking so much time to understand you...)
With best regards,
Ana

I'm glad you have made progress.   I think you will find it helpful to invest a bit of time learning more about the linux command line.
There is web site: http://gd.tuwien.ac.at/linuxcommand.org with a tutorial  that other SeaDAS users have found helpful.  

Some people just don't want to mess with the command line.  Modern linux distributions have desktop environments that are
similar to Windows and Apple GUI environments.   The SeaDAS VM uses a stripped down GUI to minimize the size of the VM, so
to get a more complete GUI you would need to either install linux as a native OS or get a full-featured VMware applicance and
install SeaDAS in that.

One note of caution -- the Windows filesystem can deteriorate badly when used for remote sensing workloads due to disk
fragmentation.   I have seen many Windows systems with a disk that has ample (>40%) free space, but only very small
contiguous regions.  In some cases running the defrag.exe repeatedly helps, but in others it is unable to make headway, and
you are faced with reformatted and reinstalliing.   In such cases it makes sense to just buy a new disk and install linux, which
does not seem to have the severe problems with fragmentation.

> Answering Mark, re. if I can access an external website - if I use the Firefox launcher on the taskbar buttons, I get the error message I have explained above, but if I click help
> while trying to do an operation it opens your website!

Ana, your virtual appliance is not connecting to the network through your Windows host.  If it was making a successful connection, you would be able to use Firefox as you normally would on any other machine.  When you click on help, it is not opening our website, it is displaying the help information that comes with seadas in a browser as it would any other local html files on your computer.  But I would add that this help utility is what we have used as our "manual" for a long time.  We do have a pdf manual that has some information about seadas, but it is a work in progress and is not comprehensive yet.  To obtain the manual, ftp anonymously to samoa.gsfc.nasa.gov and change directory to seadas/pub/shenli.  Get the SeaDAS_Manual.pdf file.  You can get other information on seadas by clicking on the Help button iin the main menu and navigating through the various pages of information.

To estimate the range of values in each pixel for a year's worth of daily images would require writing a seadas script that would load in each daily image and loop through each pixel, updating some min/max arrays along the way.  There are probably several ways to go about doing this, either with an IDL script as mentioned, or perhaps with the user-defined band function feature, but that's your challenge to read up and decide the best way to do this.  The seadas forum is also a useful tool, as it provides a search function that may well show you some previous posts that do something similar to what you're trying to do.

Regards, Mark

Hi Ana,

I hope I can help.

i. after extracting the Level 3 data using 7zip, the data is actually in HDF format but somehow the *.hdf does not appear.
ii. I use ENVI software together with EPOC extension to read this data. It can be read easily.
iii. Save the file in tiff format or ascii.
iv. u will be able to open in in ArcGis.

Its a long process but much better than nothing.

Cheers

Idham

Hi again,

After all this time, I needed to do the same procedures again, and I noticed that I did not specified here how I did it. so I decided to do it now, as it might be helpful for someone else, and also you can correct me (or let me know an easier way to do it) if that is the case. I also include some questions at the end of this post - that I have not figured out how to solve yet :S)

To be able to use the images in ArcGIS (Windows environment), I followed the steps below:

1 - Downloaded the image from the website in a bz2 format
2 - Unzipped them using 7z (no extension appears)
3 - Used Seadas to build an hdf file:
      a) After creating a "seadas_shared" folder (see links above for this) and changed the working directory in Seadas to that folder (Main Menu: Utilities -> Session Defaults -> Change default working directory)
      b) Go to Main Menu: Display -> navigate to seadas_shared -> load the unzipped files
      c) Band List Selection: Display
      d) On the diplayed image: Functions -> Output -> Display -> (select the type) Image Data -> (select the file type) HDF SD -> Go
4 - The new file is created in the shared folder and can be included in ArcGIS as a raster (define projection: Plate Carre)

And it is ready to do operations in ArcGIS as the file has information about the values for each pixel.

(Please let me know where I can improve this method, if you have any ideas - beside the questions below)

QUESTIONS:
1 - To unzip the files in Seadas and using Bzip2, which is the comand I shall use?  I tried to use: "bzip2 -d filename.bz2" but it did not work :S
2 - When I need to load the initial files, how can I select more than 1 file at the same time? Even using the Help menu, it only gives information on how to chose one file
3 - I suppose that to do this same procedure for several files, I would need to build a script, but I am not sure how to call the folders and specify files in linux, could I have any hints from you? (If someone could send me a brief example script on how to call the seadas-shared folder and code one of the display functions, that woudl be awesome!)

P.S. - I still have troubles connecting to your website via Seadas (using Firefox) to download the data
How can I download a set of images quicker than doing it one by one from the website?:S:S:S Do I need an FTP password to access your FTP and download the data?

Thank you very much for all your help.
With best regards,
Ana
With best

Ana,

Here are some answers for you:

> 1 - To unzip the files in Seadas and using Bzip2, which is the command I shall use?  I tried to use: "bzip2 -d filename.bz2" but it did not work :S

   SeaDAS does cannot uncompress the files, they must be uncompressed prior to loading into SeaDAS.  The bzip2 compression program is not part of SeaDAS,
so you must run the uncompression command outside of SeaDAS (i.e. from the shell command line NOT the seadas command line)

> 2 - When I need to load the initial files, how can I select more than 1 file at the same time? Even using the Help menu, it only gives information on how to chose one file

  SeaDAS only loads one file at a time.

> 3 - I suppose that to do this same procedure for several files, I would need to build a script, but I am not sure how to call the folders and specify files in linux, could I have any hints from you? (If someone could send me a brief example script on how to call the seadas-shared folder and code one of the display functions, that woudl be awesome!)

  You could compose a script to batch process files within SeaDAS.  There are numerous examples posted on this forum, for example:
            http://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?pid=11817

> P.S. - I still have troubles connecting to your website via Seadas (using Firefox) to download the data
> How can I download a set of images quicker than doing it one by one from the website?:S:S:S Do I need an FTP password to access your FTP and download the data?

  See the FAQ regarding bulk data downloads from our HTTP server.

Hope this helps,
Sean

See these posts for more IDL scripting examples:

http://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?tid=473
http://oceancolor.gsfc.nasa.gov/forum/oceancolor/topic_show.pl?tid=1830

Thank you for your helpful answers

Sean, I could unzip the images now, writing the comand on the right window
I will go through the scripts to try and build my own, thanks for examples.

I have just another question regarding Chla composites.
I needed to download some other images now, that I did not download last year when I first started to use them, and I noticed that the names are not the same anymore -  and also when I process the images the same way I was doing for the my older composites, I do not get good values per pixel, ie:

- Older set of images were named e.g. "S19973051997312.L3m_8D_CHLO_9.bz2" and new set are e.g. "S19973051997312.L3m_8D_CHL_chlor_a_9km.bz2" for SMI and "S19973051997312.L3b_8D_CHL.main.bz2" for Bin.
- Values for chla in the older set would vary between 0.01 and 64 and for the new data set I get strange values like -32767 to 2.4 (?)

(These images were downloaded from e.g.:
http://oceancolor.gsfc.nasa.gov/cgi/l3?per=8D&prd=CHL_chlor_a&sen=S&res=9km&num=24&date=20Jul2002 )

I could not understand what changed (?) I am downloading the wrong set of images now?

Thank you,
Ana

Ana,

What has changed is that SeaWiFS was reprocessed in the Fall of 2009:
http://oceancolor.gsfc.nasa.gov/REPROCESSING/R2009/

There were changes to the SMI files:
http://oceancolor.gsfc.nasa.gov/REPROCESSING/R2009/format/#l3mprod

Sean

Thanks Sean.

So the process should not be the same at all? I mean, I have downloaded the images I need, and I uncompressed them using SeaDas.
After that, when I try to open them in SeaDas - using the steps below, I get totally pink images :S with the range of values that I have described above - shall I not see them in the same way I was seing the other images?

Could somebody please let me know which different steps shall I follow?
I was going to:
1 - Display in Seadas, navigating to the folder where I have the uncompressed images, and pressing ok
2 - in the "product selection for SeaWiFS file" selecting Chla concentration and pressing load
3 - in the "Band list selction" chosing display (in this panel the GeoPhys Min/Max are -3.227E+04 / 2.430 ?!!??)
4 - the image appears almost completely pink (image was e.g. : S19972411997248.L3m_8D_CHL_chlor_a_9km)

Thank you very much.
Best regards,
Ana

Ana,
yes, the processing is different.
A few  things about the images.

1) Make sure you're using at least SeaDAS v6 - it knows how to interpret the new 'missing' data value attribute in the SMI files
2) Always confirm the display scaling is consistent - it is user-definable.
3) For this particular file (S19972411997248.L3m_8D_CHL_chlor_a_9km) There is only 1 small test image, hence the odd
data range (though in v6, the range is 0.01 to 2.430 ). The first complete month of SeaWiFS data acquisition was Oct 1997.
Prior to Sep 18, 1997 the instrument was undergoing engineering testing.

Regards,
Sean

Thanks Sean.

I am now using Seadas V6 and I can see the correct range for that chla image values in Seadas.
Though I am not sure if I understood what you meant by changing the display - was this in the Seadas display menu? As I am getting some identical problems in other images, e.g. S19972971997304.L3m_8D_CHL_chlor_a_9km Min=0.0005370 and Max=98.52 -> I was expecting to have a max of about 64in each image (?)

I would also like to ask if there was any change to the coordinate system defined for the images? It seems that the problem I am getting is related to the projection. It used to be Plate-Carre? Is this correct?

The procedure does not seem to have changed, as I can do exactly the same steps explained above and get the images (for MODIS Aqua images, I have no problems).
I can though display the chla images in ArcGIS but, when I try to process them i get problems - and it seems that it is because I cannot project them correctly

Do you have any idea what it might be?

Thank you very much for your help.
With best regards,
Ana

Ana,

For the bin (and subsequently, the mapped) data, the max chl could be up to 100 mg/m^3.

When you display a product in SeaDAS, you can manually adjust the display scaling (Functions->Rescale).

The coordinate system did not change, still Plate-Carre.  Sorry, I do not have an idea why ArcGIS is having
problems with the files.

Regards,
Sean

Hi again,

I am not sure if it is in ArcGIS or in Seadas though.

In Seadas I generate the Image Data (hdf) from the unzziped file. This image does not carry coordinate system with it (?) so when I try to add it to GIS i get that error for the coordinate system.
Because I can define as Plate Carre, I do so, as you confirmed.
When I display the image I get the max chla of 65.535, when in the band list selection of Seadas the min and max values are: 0.0005370 and 98.52.
(Even before defining the coordinate system - the range of values for the image are not the same as displayes n Seadas (?) Can you think of any reason for this to happen?)

Sorry about so many questions, but I am getting confused with so many different values for the max chla and not a straight forward way to actually use the data in the images :S
Am I doing something wrong in Seadas? Could you please go through the steps I am using in Seadas and let me know if you disagree / find a possible mistake somewhere (above)?

Thanks in advance.

With best regards,
Ana