[R] Retain parts of a matrix
jim at bitwrit.com.au
Mon Nov 28 09:41:25 CET 2011
On 11/28/2011 04:06 PM, Katrina Bennett wrote:
> Sorry for not being more clear.
> I'll try to explain again.
> I have a rather large DEM and I need to scale daily temperature values for
> 10 years.
> I am using the sapply function to adjust temperatures (t.mean.1.c) based on
> lapse rates across DEM points (cdem) which meet the condition of elevation
> being greater than 300m. Below ~300m the lapse rate calculate changes
> because temperatures decrease with elevation. Above ~300m the lapse rates
> calculation must account for an inversion, where temperature increases with
> What I would like as a result is the values of the DEM which are lower than
> 300m to retain a generic lapse rate adjustment, and the DEM values great
> than 300 to be treating using a different function.
If cdem is a matrix (and it looks like a vector in your example), you
where le300 is the correction for altitudes less than or equal to 300M
and gt300 is the one for altitudes greater than 300M. This works for me
with a toy function. However, I don't get the same numbers as you and
wonder if your function is doing the same as the ones I use above. Also,
why 300m in the text and 900m in the functions? Are we mixing up feet
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