Did you try: extract(stack, polygon, mean)
? On 16/05/16 22:50, Antonio Silva wrote: > Hi, > > After many trials and some reading I got what I need > > apply(vals[[1]],2,mean) > > Anyway I would welcome comments to improve this solution. > > Best regards > > Antonio Olinto > > > 2016-05-16 15:32 GMT-03:00 Antonio Silva <[email protected]>: > >> Dear R users >> >> I have a raster stack and a polygon. >> >> I want the mean value inside this polygon for each raster in the stack. >> >> I'm doing the following: >> >> vals <- extract(stack,polygon) >> colMeans(r.vals[[1]]) # only for mean values >> # or >> for (i in 1:nlayers(stack)) {print(mean(vals[[1]][,i]))} # mean or other >> parameter >> >> I also tried to use lapply, but I got only the overall mean with >> lapply(vals, FUN=mean) >> >> I wonder if there is a way to get the mean (and other parameters) for each >> layer using lapply function. >> >> Thanks in advance. >> >> Antonio Olinto >> >> > > -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081 Journal of Statistical Software: http://www.jstatsoft.org/ Computers & Geosciences: http://elsevier.com/locate/cageo/ Spatial Statistics Society http://www.spatialstatistics.info
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