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I am reading Landsat 8 Collection 1 Tier 1 Annual Raw Composite

My query is: what is the intuition behind the Annual Raw composite ?

My understanding is : We take all scenes across all path and rows in the relevant year and then compute an average ?

Is that what an Annual Raw composite is ?

My confusion is : If I average across all paths / rows, the resulting picture has no meaning/intuition?

Can someone explain ?

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This is what the EE catalogue says:

These composites are created from all the scenes in each annual period beginning from the first day of the year and continuing to the last day of the year. All the images from each year are included in the composite, with the most recent pixel as the composite value.

It is not giving you an average, it gives you the most recent, non-masked, pixel value. Note that the pixels from different dates but at the same location have been composed into a single value. Values from different locations are not mixed up in any way.

I do have to say, I'm not convinced this is a very useful image collection. You typically do this composing yourself, as you want to have more control in how they're made.

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  • I would like to say that there is no path or row number. That's my main confusion. That's what made me think that all path/rows have been averaged over. I guess I was mistaken. How exactly does one use this composite? Now it looks like we have one yearly composite for all pixels in each path / row combination? How do I extract the composite for a given path and row? In the example on the mentioned page they do a Maps.setCenter. Is there a way to create a composite for a given path / row ? Sep 6, 2022 at 10:28
  • Now that I think about it, this composite is a way of taking the most recent snapshot of a given pixel. That's the intuition behind this. Does anyone here agree / disagree? Sep 6, 2022 at 10:38
  • This is how we may create this composite at a given path and row : var dataset = ee.ImageCollection('LANDSAT/LC08/C01/T1_ANNUAL_RAW') .filterDate('2021', '2022') .filter(ee.Filter.eq('WRS_PATH', 44)) .filter(ee.Filter.eq('WRS_ROW', 34)); Sep 6, 2022 at 11:00

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