[R] some help

[jim holtman]

try this:  (provide sample data next time)

> # create some test data
> x <- data.frame(LST = runif(1000), NDVI = runif(1000, 0, 1))
> head(x,10)  # show some data
          LST       NDVI
1  0.86542839 0.95129647
2  0.88910058 0.75971649
3  0.44086718 0.86532140
4  0.99879370 0.05511501
5  0.02401490 0.92282834
6  0.56026534 0.80915721
7  0.65051596 0.03606430
8  0.25897388 0.61624609
9  0.07873261 0.85179368
10 0.09829056 0.91198307
> # create partition values
> partition <- seq(0, 1, .01)
> # add column to the data to define the partition
> x$part <- cut(x$NDVI, partition)
> head(x)
        LST       NDVI        part
1 0.8654284 0.95129647 (0.95,0.96]
2 0.8891006 0.75971649 (0.75,0.76]
3 0.4408672 0.86532140 (0.86,0.87]
4 0.9987937 0.05511501 (0.05,0.06]
5 0.0240149 0.92282834 (0.92,0.93]
6 0.5602653 0.80915721  (0.8,0.81]
> # now compute range (min/mx) for the data
> xRange <- tapply(x$LST, x$part, range)
> head(xRange, 10)
$`(0,0.01]`
[1] 0.01945995 0.83500402

$`(0.01,0.02]`
[1] 0.02267906 0.69770971

$`(0.02,0.03]`
[1] 0.01287795 0.75275416

$`(0.03,0.04]`
[1] 0.1402162 0.9960408

$`(0.04,0.05]`
[1] 0.007688249 0.691519845

$`(0.05,0.06]`
[1] 0.1047314 0.9987937

$`(0.06,0.07]`
[1] 0.002181767 0.990990999

$`(0.07,0.08]`
[1] 0.08271319 0.87609409

$`(0.08,0.09]`
[1] 0.1174585 0.8931750

$`(0.09,0.1]`
[1] 0.2331289 0.8485212



On Mon, Nov 26, 2012 at 9:56 AM, dattel_palme <dattel_palme at yahoo.de> wrote:
> Hey
>
> The code need some corrections and I would kindly ask for help.
>
> Say:
> I have a table with two columns:
> col1=LST and col2=NDVI
> i would like to sort all data by NDVI.
> in reality the NDVI ranges between 0 and 1 (although some values might be
> minus also).
> I want to sort by NDVI values and then make 100 intervals of 0.01 ndvi.
> therefore the first inerval is 0.01-0.02, the second 0.02-0.03 and so on..
> for each interval I would like to get the highest (max) and lowest (min)
> value of LST.
> It would be very helpful if this values can be written in a seperate
> table/file.
>
> Thanks you very much for help!
> Stefan
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/some-help-tp4648316p4650844.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.