1 Topic by Keith Balmer

  • Keith Balmer
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  • Registered: 23-04-2009
  • Posts: 25

Topic: Occurrence records maps are misleading

I have deduced that the "Occurrence records map" that is presented after doing a species search is plotting the orange dots in the centre of the grid square's resolution? There is no warning of this.

I was looking at https://species.nbnatlas.org/species/NBNSYS0000008331 and zoomed into TL03 to see an orange dot at Flitwick Moor, an unlikely location for the record, but it appears very precise on the map.

Using the "View map" button (oddly named as I'm already viewing a map!) gives a different map that shows only 10km resolution records in that area. Flitwick Moor is at the centre of the 10km square which is why I suppose the orange dot(s) were plotted there.

I don't therefore see the purpose of the initial Occurrence records map as it is clearly inaccurate once you begin to zoom in. Why don't we get the correct map that shows records as squares instead? If we have to have the occurrences map then could the dots be coloured according the grid ref resolution, and add a key. That would at least provide a warning that most of the dots are plotted somewhere other than where the observation actually occurred.

Keith

2 Reply by chrisjohnson

  • chrisjohnson
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  • Registered: 18-10-2011
  • Posts: 301

Re: Occurrence records maps are misleading

Thank you for highlighting this issue Keith.

There are still a high proportion fo records which are only available at the 10km grid reference resolution and in many cases, apart from a presence indication, this makes the record virtually useless.
Working on an archipelago of small islands, 10km can cover half an island and a variety of habitats, therefore placing a record in the center of a 10km square is virtually meaningless, you can end up with coastal species in a peat bog.

Once you realise that this is a mapping issue and not a problem with the original record, it begins to make sense. So as a temporary fix, perhaps there needs to be information about how the map works, and in the medium term perhaps a rethink on this particular function.

Christine

3 Reply by sratcliffe

  • sratcliffe
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  • Registered: 03-07-2017
  • Posts: 286

Re: Occurrence records maps are misleading

Yes, the orange dot is the centre of the grid, if the data was supplied as a grid reference. I agree that this is confusing.

I will ask for: 1) a message to be placed above the occurrence map stating that the records may include both point and grid based occurrences; 2) the dots to be coloured reflecting their resolution (including a legend); and 3) 'View map' to be renamed 'View interactive map'.

Sophie