SeaDAS Spectrum View

[avmehta]

Hello,
I am using SeaDAS 8.1.0 GUI for analysis of OLCI Level-2 Rrs. I have two collocated images for which I am trying view spectra. Earlier, I could compare spectra from collocated images (referred to as Master and Slave) but that feature is no longer available it seems! Is there a way to have separate Rrs spectral for the two images displayed in the same window?
Thank you.
Amita

[OB SeaDAS - knowles]

I think what you are asking about is the location of the Spectrum View tool. For SeaDAS this tool is located in the Analysis toolbar, or can be found in Menu > Optical > Spectrum View. Another way to find a tool is to type the tool name in the search field at the top right of SeaDAS 8

For any file which is identified by SeaDAS as containing a spectral component in the data, the Spectrum View tool can display all the relevant bands in a single plot across the spectrum.

To determine whether SeaDAS has identified a particular band as containing a spectral component, for an open file, in the File Manager right click on a band and select "Properties". In the Properties window for the band, if the field "Spectral Wavelength" contains a value then SeaDAS can use this spectral component in tools such as Spectrum View. If it does not contain a value, you can manually edit "Spectral Wavelength" if you wish.

[avmehta]

Hello,
I know where the 'spectrum view' is. The problem I have is with the filtering option! It is not the same as it was in the previous version! Earlier I used to be able to choose to plot Rhos or Rrs
with different symbols (for example see the attached SpectralView1) -- now it just plots all spectral components and can't tell which one is which (SpectralView2)!
Thanks.
Amita

SpectralView1.png (62.65 KiB) Not viewed yet

SpectralView1.png (62.65 KiB) Not viewed yet

[OB SeaDAS - knowles]

I don't believe the problem you are experiencing is associated with any difference between SeaDAS 8.2.0 and the prior SeaDAS 7 versions. The problem with your last plot is likely that you don't have your bands grouped together into folders in the File Manager.

See the two attached images. The bands need to be grouped into folders in order for Spectrum Plot to understand that particular bands should be grouped together in the plot.

Grouped bands

grouped.png (59.86 KiB) Not viewed yet

Ungrouped bands

ungrouped.png (56.76 KiB) Not viewed yet

To group the bands you can right click on the filename in the File Manager, then select properties, then specify the grouping in the field "Band Grouping" as a colon delimited string. For instance "Rrs:rhos:nLw"

Files such as the NASA OBDAAC level 2 files, can be loaded and recognized by SeaDAS, and predefined band groupings will be applied by default. Files which don't have a reader which specifically groups the bands, may or may not group the band depending on the metadata of the file and how the file is imported into SeaDAS.

[avmehta]

Hi Danny,
Thanks for your previous email, which was a while ago!
I have a question about grouping bands. If I am using a file with two collocated images, I have two sets of Rrs. How do I group them in different 'band groups'? I don't see a way to highlight and select bands.
Thank you.
Amita

[OB SeaDAS - knowles]

Can you post a screenshot of the File Manager GUI, it's bands in the folder, so we can know what you are trying to group? Also explain what your desired grouping is.

[avmehta]

Please see the attached image of the bands from the SeaDAS File Manager. I want to group Rrs from the two groups shown in columns 3 and 4 and plot spectra on the same plot.
Thank you for your help.
Amita

Bands.png (165 KiB) Not viewed yet

[OB SeaDAS - knowles]

Hi Amita,

SeaDAS bands cannot be grouped into folders by selectively highlighting them. However they can be grouped by specifying a colon delimited string mentioned earlier in this thread.

SeaDAS additionally supports the use of the wildcard character "*" for grouping bands. To create the particular grouping which you are asking about, in the "File Manager" GUI, right-click on the file name and select properties. Then set Band Grouping = Rrs_*_M:Rrs_*_S

forumreply.png (413.9 KiB) Not viewed yet

[avmehta]

Hi Danny,
Thanks much, this works!
Amita

[oo_processing]

Hello,

This really helps. Thanks!
However, I have a new question to ask. For some reasons, our data files read (for example) 'Rrs_443' instead of 'Rrs_443 (443.0 nm)' in SeaDAS (I have the latest 9.0.1). Using 'Band Grouping', I can have all Rrs_xxx grouped, but 'Spectrum View' stops at 'Collecting spectral information...'
Right click 'Rrs_443' -> Properties -> Spectral Wavelength = 0.0; I think that's the reason. I typed in numbers, then the 'Spectrum View' works. So, can I suggest a function, let 'Band Grouping' smartly grab the number and fill in the 'Spectral Wavelength' property?

Thanks!
Yuyuan