I have a binary file(a) with size of (360 720 )for the globe.I wrote the code
given below to read and extract an area (south america)from that file. when
I use summary for the whole file I got:
summary(a, na.rm=FALSE)
Min. 1st Qu. Median Mean 3rd Qu. Max. NA's
0.00 1.00 3.00 4.15 7.00 20.00 200083 .
But when I used summary for the region(b) which I extracted, I got many
V1,V2, V3. Which is not right I should have got one line (as for a )not many
V1,V2.
Here is the code:
X <- c(200:300)
Y <- c(150:190)
conne <- file("C:\\initial-WTD.bin", "rb")
a=readBin(conne, numeric(), size=4, n=360*720, signed=TRUE)
a[a == -9999] <- NA
y <- matrix(data=a,ncol=360,nrow=720)
image(t(t(y[X,Y])),ylim=c(1,0))
b = y[X,Y]
summary(b,na.rm=TRUE)
V1 V2 V3 V4 V5 V6
V7
Min. : 1.000 Min. : 1.000 Min. : 1.000 Min. : 1.000
Min. : 0.000 Min. : 0.000
1st Qu.: 4.000 1st Qu.: 4.000 1st Qu.: 4.000 1st Qu.: 3.000 1st
Qu.: 2.000 1st Qu.: 2.000
Median : 5.000 Median : 6.000 Median : 5.000 Median : 5.000 Median
: 5.000 Median : 5.000
Mean : 5.808 Mean : 5.962 Mean : 5.506 Mean : 4.946 Mean
: 5.068 Mean : 4.829
3rd Qu.: 6.750 3rd Qu.: 7.000 3rd Qu.: 7.000 3rd Qu.: 6.000 3rd
Qu.: 7.000 3rd Qu.: 6.000
Max. :18.000 Max. :19.000 Max. :17.000 Max. :13.000 Max.
:19.000 Max. :18.000
--
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David Winsemius
2012-Jun-13 17:32 UTC
[R] How to calculate the statistcs for extracted region?
On Jun 13, 2012, at 12:55 PM, Jonsson wrote:> I have a binary file(a) with size of (360 720 )for the globe.I wrote > the code > given below to read and extract an area (south america)from that > file. when > I use summary for the whole file I got: > summary(a, na.rm=FALSE) > Min. 1st Qu. Median Mean 3rd Qu. Max. NA's > 0.00 1.00 3.00 4.15 7.00 20.00 200083 . > > But when I used summary for the region(b) which I extracted, I got > many > V1,V2, V3. Which is not right I should have got one line (as for > a )not many > V1,V2.Actually the expected behavior with summary() on a matrix object is a column by column summary. > summary(matrix(1:16,4)) V1 V2 V3 V4 Min. :1.00 Min. :5.00 Min. : 9.00 Min. :13.00 1st Qu.:1.75 1st Qu.:5.75 1st Qu.: 9.75 1st Qu.:13.75 Median :2.50 Median :6.50 Median :10.50 Median :14.50 Mean :2.50 Mean :6.50 Mean :10.50 Mean :14.50 3rd Qu.:3.25 3rd Qu.:7.25 3rd Qu.:11.25 3rd Qu.:15.25 Max. :4.00 Max. :8.00 Max. :12.00 Max. :16.00> > Here is the code: > X <- c(200:300) > Y <- c(150:190) > conne <- file("C:\\initial-WTD.bin", "rb") > a=readBin(conne, numeric(), size=4, n=360*720, signed=TRUE) > a[a == -9999] <- NA > y <- matrix(data=a,ncol=360,nrow=720) > image(t(t(y[X,Y])),ylim=c(1,0)) > b = y[X,Y] > summary(b,na.rm=TRUE) > > V1 V2 V3 V4 > V5 V6 > V7 > Min. : 1.000 Min. : 1.000 Min. : 1.000 Min. : > 1.000 > Min. : 0.000 Min. : 0.000 > 1st Qu.: 4.000 1st Qu.: 4.000 1st Qu.: 4.000 1st Qu.: 3.000 > 1st > Qu.: 2.000 1st Qu.: 2.000 > Median : 5.000 Median : 6.000 Median : 5.000 Median : 5.000 > Median > : 5.000 Median : 5.000 > Mean : 5.808 Mean : 5.962 Mean : 5.506 Mean : 4.946 > Mean > : 5.068 Mean : 4.829 > 3rd Qu.: 6.750 3rd Qu.: 7.000 3rd Qu.: 7.000 3rd Qu.: 6.000 > 3rd > Qu.: 7.000 3rd Qu.: 6.000 > Max. :18.000 Max. :19.000 Max. :17.000 Max. :13.000 > Max. > :19.000 Max. :18.000 >This is cross-posted from SO. It is no more reproducible here than it was there. Cross-posting is deprecated on Rhelp. Please read the Posting Guide.> > -- > View this message in context: http://r.789695.n4.nabble.com/How-to-calculate-the-statistcs-for-extracted-region-tp4633295.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.David Winsemius, MD West Hartford, CT