Overlay and spatialgrid
Ervan,
You can do something like
library(raster)
r <- raster(Grid2)
r <- pointsToRaster(r, xy=temp[, c('x', 'y')], values=temp[,'z'], fun=max)
plot(r)
x <- as(r, 'SpatialGridDataFrame')
On Tue, Sep 21, 2010 at 2:29 AM, Ervan Rutishauser
<ervan.rutishauser at cirad.fr> wrote:
Dear all, I wonder if it is possible to compute a statistic (mean, max) of a SpatialPointsDataFrame object using a SpatialGrid. I tried it that way, but did not get what I wanted: # 1. Create a grid bonding the region studied Grid<-GridTopology(c(284600,580550),c(5,5),c(600,850)) Grid2<-SpatialGrid(Grid) # 2. An example of my data
head(temp)
? ? ? ? x ? ? ? ? ? ? ? ? ? ? y ? ? ? ? ? z ? R ? G ? B ? I 1 284999.1 583538.0 ?9.76 11 10 ?8 65 2 284998.2 583537.1 ?6.40 10 ?4 11 69 3 284999.9 583536.1 28.70 ?8 ?8 ?4 75 4 284996.7 583535.9 12.55 ?4 ?3 ?0 63 5 284996.8 583533.8 ?7.64 16 ?6 10 75 6 284997.3 583532.5 26.46 11 ?9 10 74 coord<-coordinates(matrix(c(temp$x,temp$y),ncol=2)) Z<- data.frame(Z=temp$z,I=temp$I) lidar<-SpatialPointsDataFrame(coord,Z) test<-overlay(lidar, Para_gr) # I would like to compute the maximum of z in each cell of the grid. Thank you for any help. All the best, Ervan
______________________________________________________________________ Ervan Rutishauser CIRAD - UMR AMAP PS1-Bd de la Lironde 34398 Montpellier cedex 5 phone: 04.67.61.58.00 ? ? ? ?[[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo