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Centroid (only fully contained squares)

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Centroid (only fully contained squares)

by jdsh » Fri Jun 05, 2020 5:43 pm

This constraint doesn't seem to work as I would expect, as it gives results for partially contained squares as well. A circle of radius 5657m should define an 8x8km complete box, with 64 fully contained monad squares. The search returns results from the fragmentary squares as well.

What I actually want to do is compute species totals for the full 8km square, as well as the individual monads.

The bounded area search doesn't seem to allow definition of a bounded area by giving two or more positions which could be an alternative approach.

Jon
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Re: Centroid (only fully contained squares)

by admin » Fri Jun 05, 2020 6:52 pm

Hi Jonathan,

The search is considering records at any precision so, at the periphery, will allow precise (sub-monad scale) records that, if expressed at monad scale, would be excluded.

The radius is taken from the mid-point of the monad that you specified, i.e. TL4658 => TL465585

The monad grouping constraint is applied after the records are filtered.

It would be good to be able to draw an arbitrary boundary to search, as you suggest. Without that the best option may be to specify the list of monads (which is obviously far from ideal) - I don't think there's a straightforward way to use a circle to define the square area that you are after.

e.g.

https://database.bsbi.org/search.php#re ... ce3bd6a452
Tom Humphrey
Database Officer, Botanical Society of Britain and Ireland (BSBI)
c/o Centre for Ecology and Hydrology,Maclean Building, Crowmarsh Gifford, Wallingford, Oxon, OX10 8BB, UK.
tom.humphrey@bsbi.org
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