[prev in list] [next in list] [prev in thread] [next in thread] 

List:       r-sig-geo
Subject:    Re: [R-sig-Geo] Spatial maximisation problem using polygons
From:       "Robert J. Hijmans" <r.hijmans () gmail ! com>
Date:       2014-09-19 14:01:41
Message-ID: CANtt_hyMTs4V_xDey5UUO36+nm4togks7USYUrtysxPWNXAKjw () mail ! gmail ! com
[Download RAW message or body]

Rui,
You could create a matrix (=raster) and a function that creates a
valid set of groups of 4 cells that are not adjacent. The function
should return the solution (output matrix values: TRUE or FALSE) and
the sum of the selected values. Then use the optim function to
optimize based on the sum. When you have an optimal solution, create a
raster from the matrix and coerce that to polygons.

On Fri, Sep 19, 2014 at 2:18 AM, Rui Catarino <R.Catarino@marlab.ac.uk> wrote:
> Hi,
> 
> This is not a very objective question and I apologise for that in advance.  What \
> I'm really looking for is some pointers on where to start or where to look for \
> information. I've been looking in the web for the last couple of days and found \
> very little. That might be because I'm failing in using the right key words or R is \
> not the tool which I doubt, so here I am asking the experts. 
> So basically I have a grid in which, each cell is a square and it has a certain \
> value. The grid values change every week and every week I need to generate multiple \
> polygons of fixed size (4 cells of the grid). The polygons value (sum of cell \
> values) should be maximised but polygons cannot be adjacent and need to have a \
> spacing of at least one cell between them. 
> The task will get a lot more complex with a few more constrains but I think if I \
> get some pointers, papers or similar examples I could start from there. I can \
> generate the grid but I failed to find similar examples in the internet on regular \
> polygon placement or maximisation. 
> Any help will be very much appreciated.
> Cheers
> 
> 
> Rui Catarino
> Data Analyst/Modeller
> Fishery Analysis and Assessment Group
> Marine Scotland - Science
> 
> Scottish Government | B15 | Marine Laboratory, 375, Victoria Road | Aberdeen AB11 \
> 9DB 
> Tel:  +44 (0)1224 295572
> Mob:+44 (0)7530 240666
> Fax: +44 (0)1224 295511
> r.catarino@marlab.ac.uk<mailto:r.catarino@marlab.ac.uk>
> rui.catarino@scotland.gsi.gov.uk<mailto:rui.catarino@scotland.gsi.gov.uk>
> www.scotland.gov.uk/marinescotland<http://www.scotland.gov.uk/marinescotland>
> 
> 
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please visit http://www.symanteccloud.com
> ______________________________________________________________________
> [[alternative HTML version deleted]]
> 
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo


[prev in list] [next in list] [prev in thread] [next in thread]