Thank you very much to both. Manuel
2017-03-04 6:35 GMT-06:00 Marcelino de la Cruz Rot < marcelino.delac...@urjc.es>: > My apologies for such a pair (or more) of embarrassing mistakes! > > I should read a bit more these days... > > > Marcelino > > > > > El 04/03/2017 a las 2:31, Rolf Turner escribió: > >> On 04/03/17 08:38, Marcelino de la Cruz Rot wrote: >> >>> Hi Manuel, >>> >>> I do answer to the question "How can I make a spatial grid of 1 ha (or >>> other size) in R?" >>> >>> You can use function hextess in spatstat >>> >>> library(spatstat) >>> >>> # some arbitrary area, with coordinates in hectometres >>> W <- Window(chorley) >>> >>> # As Rolf said, hexagons of 1ha should have side of 402.0673 metres, so, >>> in hectometres: >>> >>> s <- 4.020673 >>> >>> plot(hextess(W, s)) >>> plot(hexgrid(W, s), add=TRUE) >>> >> >> Marcelino, >> >> Actually I said hexagons of area *42* ha should have side length equal to >> 402.0673 metres. >> >> Moreover the Chorley data set has units of *kilometres* not hectometres, >> so that should be s <- 0.4020673. Or, to avoid just a touch of round-off >> error, s <- sqrt(2*0.42)/3^0.75. >> >> Note that if you then do >> >> xxx <- hextess(W,s,trim=FALSE) >> unique(sapply(tiles(xxx),area.owin)) >> >> you get 0.42 --- i.e. 0.42 square kilometres, or 42 hectares. >> >> cheers, >> >> Rolf >> >> > > -- > Marcelino de la Cruz Rot > Depto. de Biología y Geología > Física y Química Inorgánica > Universidad Rey Juan Carlos > Móstoles España > > -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.cr <mspin...@una.ac.cr> mspinol...@gmail.com Teléfono: (506) 8706 - 4662 Personal website: Lobito de río <https://sites.google.com/site/lobitoderio/> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/> [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo