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CMR and page sizing #15

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matthewhanson opened this issue Jan 13, 2017 · 0 comments
Closed

CMR and page sizing #15

matthewhanson opened this issue Jan 13, 2017 · 0 comments

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@matthewhanson
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So, how CMR works is that when you request data from a date it returns any product which includes that date within it's range. So, for MODIS data you get data for 8 days before and 7 days after in the query result.

Additionally, CMR's date field is always the 1st day of the 16 day window rather than the middle, even though the version 006 MCD43A4 filenames use the 9th day in the naming (and version 005 uses the first)...CMR always uses the first.

So, if you request a date from CMR of MCD43A4.006 without a polygon feature, you get all tiles from every day starting 16 days before your requested date. With 460 tiles per day clearly this is more than the 1000 page limit size we have yet (and whose maximum is 2000).

Note that the CMR query python code will actually throw out all the other dates that aren't the actual specific date...the problem is that we aren't requesting multiple pages from CMR. We need the code to be able to fetch all the results no matter how many there are.

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