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RE: pixel resolution after binning
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pixel resolution after binning
modis binning
5/11/17 5:32 AM
Hi.

I'm using gpt.sh Binning to bin MODIS aqua data. I wonder about the difference I get when binning with
Setting 1: numRows = 19440 and superSampling = 4. This yields pixel size of 1.03 km as parameters info found in the Metadata. Visually smooth features and the best of 3 settings as can be seen in the attachments.
Setting 2: numRows = 4860 and superSampling = 1. This yields pixel size of 4.12 km and coarser pixels.
Setting 3: numRows = 19440 and superSampling = 1. This yields pixel size of 1.03 km and lots of gaps between pixels.

I've read IOCCG Report 4 and thought Settings 1 and 2 would yield a pixel resolution of 4.12 km but the results are very different. Why are they different? My question is: what is the actual size of the pixel as binning result for above three settings?

Many thanks.
Claudia
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Attachments: chlor_a_mean_binning_nRows19440_sSamp1.png (329.0k), chlor_a_mean_binning_nRows19440_sSamp4.png (309.1k), chlor_a_mean_binning_nRows4860_sSamp1.png (85.1k)
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RE: pixel resolution after binning
5/11/17 9:43 PM as a reply to Claudia Omachi.
I think what you observe is the moiré effect.
When using the 1 km output with supersampling of 4 the moiré effect is avoided. The moiré effect does also not occur when using the 4km output.
But having 1km output and no supersampling the super moiré effect occurs.
You can find more about it in the help.
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Attachments: screen.png (534.1k)
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RE: pixel resolution after binning
modis binning
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5/18/17 10:28 PM as a reply to Marco Peters.
Hello.

Thank you for the help link for Moiré effect. Would you tell the 1km output with supersampling of 4 results in 4 km pixel? It doesn't seem so because the 4km pixel is much coarser...
The information in parameters within Metadata keeps 1km pixel with supersampling of 4 but does not detail the actual size of the ground represented in a resulting pixel.

Well, I'd rather write 1km pixel with supersampling of 4 in the article...

Thank you.
Claudia
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