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Mac OS X | Polygon count on 1 km Grid

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#1
Felix

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Dear all,

I am struggling to find an elegant way to create species richness maps. I thought there would be a rather simple and straightforward method to proceed but I could not find it using a Mac and QGIS -- are any other Mac softwares, if necessary.

I'm using IUCN data available here: http://www.iucnredli...ts/spatial-data
There are about 5,500 species of mammals. I wish to count how many polygons (1 poly = 1 species) are present per square based on, say, a 1 km grid. And then assign colours according to the species density in each square. Simple. But how? Struggle.

Does somebody know how to meet this challenge (challenge, that is, at least for me)?

I would be enormously grateful.

Thanks,

Felix
www.globaia.org

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#2
kay

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I assume you have grid data in vector format. If so.. how about using "Spatial Join".

Kay

#3
frax

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Maybe there is an easier way, but I would create a python script that looped over all the species and first rasterized them to your grid, with a value of 1 inside the range and 0 outside, and then you can just add them up to create a heatmap.
Hugo Ahlenius
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