< Export Transect Pixels > yields only 'Invalid Pos.' for all products

Optical Toolbox Sentinel 3 Problem Reports
#1

Hello All,

I really need this data ASAP and would appreciate any insight you can give! :slight_smile:

I’m looking at eddies using the NN_CHL product, and am trying to take a transect of Chlorophyll values across the eddy. I drew a line with the line-drawing tool, right-clicked, and selected ‘Export Transect Pixels’. This opens the following pop-up:
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This allowed me to copy the data to clipboard or to a .txt file. I have tried both. Each time I export the pixels, the data I’m given is x pixel, y pixel, lat, and lon. These columns are filled in correctly. However, every other data column (all the wavebands and products, etc) is filled with ‘Invalid pos.’. :frowning:

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Any ideas why it’s not retrieving the products for my transected pixels?

Thank you!!!

Many thanks,
Em

#2

are you able to plot the chlorophyll profile along the digitized line?

You can switch to a table view there as well

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#3

@ABraun thank you for your reply!

I’m not sure… I am new to snap and don’t know how to plot the intensity along the transect. There is no option for this when I right click on the transect.

Is there a different way to create a transect, other than drawing a line?

Thank you!

#4

once you have digitized a line you can click on this icon in the toolbar: grafik

This opens the profile plot view.

1 Like
#5

Thank you!

#6

has it worked?

#7

Yes thank you! only issue now is that it seems to show the same exact plot even when I’ve closed the old one and plotted a new transect (doesn’t always update the profile plot when I select a new transect)… maybe just slow processing…

#8

that’s possible. Sometimes it’s enought to set the Box size to 4 and then back to 3 for the plot to update.

#9

Hi! I am having a problem with the export/import of transect pixels. This is something we could do in previous versions of SNAP, and now it seems not to be possible. I have the same scene in two levels: OLCI L1 and L2. I would like to compare the profile plots of the same band in the two levels using exactly the same pixels. So I draw a line, I export it, but later I am not able to import it back into the new scene. I guess it has to do with the “Invalid pos.” Is this a known problem?

#10

I got a solution, not ideal, but it works. Open the transect.txt with and editor and remove all columns containing information other than the position. In that way I have been able to import it. Still, something is not right.

1 Like