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I downloaded a monthly precipitation data in netcdf format from NOAA (CPC Unified guage). The data were stored in mm/day and I need to multiply each layer with counts of their respective month to get the total precipitation for the month. For instance, a layer for September 1969 will be multiplied by 30 while the layer for February will be multiplied by 28. Also, there's a problem of leap years when February layers will have to be multiplied by 29.

I tried some codes (see below) but are not working. 

prec <- brick(precip.V1.0.mon.mean.nc)                                                         
conv <- function(x, ...) {
  ifelse(x == c(01, 03, 05, 07, 08, 09, 10, 12), 
         31 * x, 
         x, 
         ifelse(x == c(04, 06, 11), 
                30 * x, 
                x, 
                ifelse(x == 02, 
                       28 * x, 
                       x)))
  } # function for the conversion

## pulling out date indices for each month
indices <- as.numeric(format(as.Date(names(prec), format = "X%Y.%m.%d"), format = "%m")) 

## applying the function using stackApply
new_prec <- stackApply(prec, indices, fun = conv)

Error in ifelse(x == c(1, 2, 3, 5, 7, 8, 9, 10, 12), 31 * x, x, ifelse(x == : unused argument (ifelse(x == c(4, 6, 11), 30 * x, x, ifelse(x == 2, 28 * x, x)))

And when I tried to pass the function using a simplified version (e.g.) ifelse(x == 12, 30*x, x) I got the following error

Error: Error in (function (..., deparse.level = 1) : number of rows of matrices must match (see arg 2)

I was wondering if anyone has tips for the conversion.

Here's a link to a subset of the the data: https://fil.email/VahwQq8p

user11384727
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  • Please provide a [reproducible minimal example](https://stackoverflow.com/q/5963269/8107362). Especially, provide some sample data, e.g. with `dput()`. – mnist Nov 25 '19 at 20:38
  • add first glance, what is your fourth argument in `ifelse()`? – mnist Nov 25 '19 at 20:39
  • wusel, if you are referring to "x", it means to return the original value. dput() seems handy. I hope to get familiar with it. In the meantime, I have provided a link to a subset of my data. – user11384727 Nov 25 '19 at 21:05

0 Answers0