[R-sig-Geo] How to calculate slope in rasterbrick

[Robert Hijmans]

> I have a brick that contains 348 layers. Each layer is small in 
> dimension ncol=69, nrow=43. My question is, how do I calculate slopes 
> for each pixels from layer 1 to layer 348(Month one to months 348). I 
> am trying to find the trend as I am working with time series data. 


for RasterBrick 'b'

time <- 1:nlayers(b)
fun <- function(x) { lm(x ~ time)$coefficients[2] }
x <- calc(b, fun)

x is a RasterLayer with the slope of a linear regression model for each
cell.

Robert


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