PlanetScope imagery appears green over ice

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Karen Alley

Hi there,

I'm working on looking at surface meltwater on glaciers, which is generally pretty easy to spot in RGB composites. However, when I import some of the composites I've downloaded (although not all of them), the ice appears very green in RGB. I'm assuming the actual RGB values are correct and this is some sort of automatic scaling problem, but I'm not sure how to go about fixing it. Any ideas? Screenshot below. I appreciate any help!

-Karen-

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    Pooja Pandey

    Hi Karen,

     

    Thank you for bringing this up.

    Would you be able to tell me what image id this is, so i can take a further look into this?

     

    Best Regards,

    Pooja

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  • Karen Alley

    Hi Pooja,

    Thanks for the help! Are the image IDs in the filename? If so, here are the ones from the screenshot I posted:

    20180809_203818_1018_3B_AnalyticMS

    20180809_203817_1018_3B_AnalyticMS

    Actually, though, here's a place that might be better to start - one of my students has been looking at similar images from Helheim glacier in Greenland, and she has an example where one image shows up looking fine and the image next-door is very green. Here's her screenshot and filenames:

    Good Helheim: 20180807_115821_0f32_3B_AnalyticMS

    Green Helheim: 20180807_115822_0f32_3B_AnalyticMS

    We've had this green problem in both ArcMap and QGIS.

    Thanks for your help!

    -Karen-

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  • Pooja Pandey

    Hi Karen,

    Thank you for the information.

    I will be in contact with your shortly over this.

    Best Regards,

    Pooja

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  • Karen Alley

    Hi Pooja,

    Any updates on this? I'm anxious to find out whether these images will be usable for our research!

    Thank you for your time!

    -Karen-

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  • Karen Alley

    Hi there, 

    Sorry, not trying to be obnoxious on this - just thought I'd add some more info! This one's a little weirder - I've got a couple scenes from West Greenland that have the green, but this time lots of pink, and a strange switch in color mid-scene:

    These are 20180701_143855_1009 and 20180701_143856_1009. 

    I had previously assumed that the values for each band could be trusted, and this must just be a scaling issue, but the switch in color in the middle of the scene worries me, particularly since it doesn't completely disappear when I switch to a single-band grey scaling (this is using the red band):

    Please let me know if you have any insights as to whether these data can be reliably used. Thank you!

    -Karen-

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  • Ed Rhodes

    I realize that this is an old question, but i think you may need to adjust the bands being used in the ArcGIS symbology tab. Blue is band 1, green is band 2, red is band 3, and NIR is band 4. ArcGIS defaults to Bands 1,2,3 for RGB, when Planetscope is ordered in BGR.

     

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  • Anja Wendt

    Hello,

    are there any insights regarding the green ice yet? It would be interesting to know how to fix it.

    I have the same problem (as in the first image) for a glacier in the Alps using AnalyticMS_SR data of a PS2 instrument, although the bands are assigned correctly.

    I'll be grateful for any help

    Anja

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