1 Topic by Jimmy.McKellar

  • Jimmy.McKellar
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  • Registered: 31-10-2013
  • Posts: 2

Topic: Two species interactive mapping

The problem:

When two species are mapped on the interactive map one over-writes the other.

The result is meaningless, any square may be showing both, or only one, species.  How can one guess which species is overwriting the other or what is behind?

The solution:

What is needed is the ability to plot two species on one map, but to have squares where both occur in an intermediate colour or the solution may be as simple as a square dissected with a diagonal line (bottom left to top right) with one colour on each side of the line.  Clear simple and oh so much more useful!

Regards
Jimmy McKellar

2 Reply by Graham French

  • Graham French
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  • Registered: 23-05-2006
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Re: Two species interactive mapping

Hello Jimmy

The Interactive Map does not display coincidence mapping as you describe. Each species layer is added separately and does not interact with one another to display intermediate colours / different symbols. I have added your request for coincidence mapping functionality but am not sure it would be that simple to implement without significantly reducing the map performance ie each time a species layer is added to the map the system needs to first calculate your access, and work out which squares coincide before creating the layers and displaying them on the map.

You do not need to guess which species is on top of the other. The order the species layers are displayed on the map is determined by their position in the legend. This position can be changed by dragging and dropping the species layer, bringing the species you wish to see at the top of the map to the top of the legend. You can also change the opacity of the layer through its edit control (spanner icon)

Best wishes

Graham
NBN Technical Liaison Officer

Graham French's Website

3 Reply by Syrphus

  • Syrphus
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  • From: Strathpeffer, Highland
  • Registered: 16-12-2008
  • Posts: 535

Re: Two species interactive mapping

I cannot understand why anyone would want to plot two or more species on one map unless the sp1, sp2, AND sp1+sp2 dots were different colours, except possibly where the only aim was to show completely allopatric ranges, when the colours may be irrelevant anyway.  Yes you can toggle the layers on and off, and change order, but if that is what was wanted you are doing little more than showing a series of single-species maps with more hassle than you have through the grid map link.

You can fiddle about with settings and eventually get a map like the attached, but the results are not wonderful.  Maybe someone can explain where the current defaults are useful for >=2 spp., and why we have this facility but not the patently useful multispecies plot, but it seems to me that this was put in less for the benefit of users than for the entertainment of the programers.

Meanwhile, a few minor (but carefully-considered) changes to the settings for the default colours in the IMT would improve the appearance and usefulness of the IMT and save anyone who wants a (slightly kludged) multi-species display having to experiment and set colour properties every time.

M.

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