Dear colleagues. I have 4 equal-sized rasters respecting 4 climate variables. I would like to have for each cell the weighted-average climatic distance (in the Euclidean space defined by the 4 variables) to its 8 closest neighboring cells, with weight related to the geographic distances. Can someone guide me on how to do it? Thanks in advance, Best regards, Diogo Alagador MED, University of ?vora, Portugal
focal point with function using multiple rasters
5 messages · Sarah Goslee, Roozbeh Valavi, Diogo André Alagador
Hi, Since you are starting from scratch, I'd suggest looking into the terra package, documented here: https://rspatial.org/terra/pkg/index.html The focal() function is probably what you're looking for, but you will need to read some of the docs to learn how to load and work with raster data in general. You'll also need to think more rigorously about how you want to calculate climatic distance for an individual grid cell. The distance() function in terra might help, but it isn't clear to me which of the many approaches you wish to implement. Sarah
On Tue, Mar 16, 2021 at 9:58 AM Diogo Andr? Alagador <alagador at uevora.pt> wrote:
Dear colleagues.
I have 4 equal-sized rasters respecting 4 climate variables.
I would like to have for each cell the weighted-average climatic distance
(in the Euclidean space defined by the 4 variables) to its 8 closest
neighboring cells, with weight related to the geographic distances.
Can someone guide me on how to do it?
Thanks in advance,
Best regards,
Diogo Alagador
MED, University of ?vora, Portugal
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Sarah Goslee (she/her) http://www.numberwright.com
Dear Sarah Thank you your suggestion. My doubt if the function to use in focal may use data from other multiple rasters. To say: I need to use the 4 climate rasters to define the climate of each cell in the climatic space. Then I need to compute for each cell the Euclidean climatic distance in the 4D space to climates of each neighboring cell. Followed by an weighted average using spatial distance among the focal and enamoring cells. Is this really implementable in a cost-effective way? Kind regards, Diogo Alagador MED, University of ?vora, Portugal
Hi Diogo, Functions like focal only work with a single layer raster. You might need to loop through all the cells and extract focal values with *getValuesFocal* (from raster) or *values* (from terra) and calculate your metric. Tho there might be a more efficient solution for this. Cheers, Roozbeh Valavi The Quantitative & Applied Ecology Group <http://qaeco.com/> School of BioSciences, The University of Melbourne, VIC 3010, Australia *Mobile*: +61 423 283 238 | *Twitter*: @ValaviRoozbeh | *Researchgate <https://www.researchgate.net/profile/Roozbeh_Valavi>* On Wed, Mar 17, 2021 at 2:48 AM Diogo Andr? Alagador <alagador at uevora.pt> wrote:
Dear Sarah Thank you your suggestion. My doubt if the function to use in focal may use data from other multiple rasters. To say: I need to use the 4 climate rasters to define the climate of each cell in the climatic space. Then I need to compute for each cell the Euclidean climatic distance in the 4D space to climates of each neighboring cell. Followed by an weighted average using spatial distance among the focal and enamoring cells. Is this really implementable in a cost-effective way? Kind regards, Diogo Alagador MED, University of ?vora, Portugal
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Dear Roozbeh. Thank you by your suggestion. Although it seems like a very much busy way to get what I need I was expecting (afraid) that was the real solution to move. Best regards, Diogo Alagador MED, University ?vora, Portugal De: Roozbeh Valavi <rvalavi at student.unimelb.edu.au> Enviada: ter?a-feira, 16 de mar?o de 2021 23:42 Para: Diogo Andr? Alagador <alagador at uevora.pt> Cc: Sarah Goslee <sarah.goslee at gmail.com>; r-sig-ecology at r-project.org Assunto: Re: [R-sig-eco] focal point with function using multiple rasters Hi Diogo, Functions like focal only work with a single layer raster. You might need to loop through all the cells and extract focal values with getValuesFocal (from raster) or values (from terra) and calculate your metric. Tho there might be a more efficient solution for this. Cheers, Roozbeh Valavi <http://qaeco.com/> The Quantitative & Applied Ecology Group School of BioSciences, The University of Melbourne, VIC 3010, Australia Mobile: +61 423 283 238 | Twitter: @ValaviRoozbeh | Researchgate <https://www.researchgate.net/profile/Roozbeh_Valavi>
On Wed, Mar 17, 2021 at 2:48 AM Diogo Andr? Alagador <alagador at uevora.pt <mailto:alagador at uevora.pt> > wrote:
Dear Sarah Thank you your suggestion. My doubt if the function to use in focal may use data from other multiple rasters. To say: I need to use the 4 climate rasters to define the climate of each cell in the climatic space. Then I need to compute for each cell the Euclidean climatic distance in the 4D space to climates of each neighboring cell. Followed by an weighted average using spatial distance among the focal and enamoring cells. Is this really implementable in a cost-effective way? Kind regards, Diogo Alagador MED, University of ?vora, Portugal _______________________________________________ R-sig-ecology mailing list R-sig-ecology at r-project.org <mailto:R-sig-ecology at r-project.org> https://stat.ethz.ch/mailman/listinfo/r-sig-ecology