Hi Jim,
Thanks for your advice. The problem is that I can't lose any of the data - it's
a global dataset, where the left-most column = 180 degrees west, and the
right-most is 180 degrees east. The top row is the North Pole and the bottom
row is the South Pole.
I've got 512MB RAM on the
If you can reduce the size of your data by averaging, then you could
read in a subset of the rows, average the 6x6 matrices and then write
them out for a second phase of processing. The 2160x4230 object would
take up 75MB if numeric, which is probably 50% of your available
memory if you are
Ok thanks Jim - I'll give it a go! I'm new to R, so I'm not sure how I'd go
about performing averages in subsets... I'll have a look into it, but any
subsequent pointers would be gratefully received as ever!
I'll also try playing with it in Access, and maybe even Excel 2007 might be
able to
Please find below my command inputs, subsequent outputs and errors that I've
been receiving.
crops - read.table(crop2000AD.asc, colClasses = numeric, na=-)
str(crops[1:10])
'data.frame': 2160 obs. of 10 variables:
$ V1 : num NA NA NA NA NA NA NA NA NA NA ...
$ V2 : num NA NA NA NA
In the first case, 'crops' is an object that is 142MB in size, and
that alone will take up almost 50% of your memory. You are also
probably generating another object of like size in doing the
operation. Can you cut down the size of the objects that you need.
What operating system do you have and
: Tue, 29 Jul 2008 15:34:31 -0400
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [R] Coarsening the Resolution of a Dataset
CC: r-help@r-project.org
I assume that you are doing this on one column of the matrix which
should only have 2160 entries in it. can you send the actual code
: Tue, 29 Jul 2008 15:34:31 -0400
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [R] Coarsening the Resolution of a Dataset
CC: r-help@r-project.org
I assume that you are doing this on one column of the matrix which
should only have 2160 entries in it. can you send the actual code
to read in the data (using
read.table) and then the code that you supplied. I could send you the actual
dataset if you don't mind a file ~50MB?!
Thanks again,
Steve
Date: Tue, 29 Jul 2008 15:34:31 -0400
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [R] Coarsening
Unfortunately, when I get to the 'myCuts' line, I receive the following error:
Error: evaluation nested too deeply: infinite recursion / options(expressions=)?
...and I also receive warnings about memory allocation being reached (even
though I've already used memory.limit() to maximise the
I assume that you are doing this on one column of the matrix which
should only have 2160 entries in it. can you send the actual code you
are using. I tried it with 10,000 samples and it works fine. So I
need to understand the data structure you are using. Also the
infinite recursion sounds
Dear all,
I have gridded data at 5' (minutes) resolution, which I intend to coarsen to
0.5 degrees. How would I go about doing this in R? I've had a search online and
haven't found anything obvious, so any help would be gratefully received.
I'm assuming that there will be several 'coarsening'
Here is one approach for using the average of each interval:
# generate some test data; assume 1.0 is one degree
min.5 - 5 / 60 # portion of degree for 5 minutes
n - 100 # number of data points
myData - cbind(interval=seq(0, by=min.5, length=n), value=runif(n))
# create breaks every 0.5
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