Re: [R] converting csv to image file
Dear Simon,
I understand better now and it is running.
//Belay
On Sat, May 19, 2012 at 1:22 PM, Simon Knapp wrote:
> I'm not sure what line you mean. The thing you pass to raster should
> be a matrix of the dimensions of your image data.
>
> You should have have xmin, xmax, ymin and ymax defined as something like:
>
> xmin <- min(x) - cw/2
> xmax <- max(x) + cw/2
> ymin <- min(y) - cw/2
> ymax <- max(y) + cw/2
>
> presuming that your x and y correspond to cell centres and where cw is
> your cell width (and if it is different in the two directions then you
> would 'cw.x' and 'cw.y'... if you know what I mean).
>
> Cheers,
> Simon
>
>
> On Sat, May 19, 2012 at 9:42 PM, Belay Gebregiorgis
> wrote:
> > Thanks Simon. I have other vectors in the CSV file so after naming my
> > latitude and longitude x and y, I tried this. The first two lines run
> fine
> > but I get error in the second line.
> >
> >
> > r <- raster(as.matrix(F1))
> > extent(r) <- extent(xmin, xmax, ymin, ymax)
> > F1<-data.frame(x, y,z)
> >
> > Error in function (classes, fdef, mtable) :
> > unable to find an inherited method for function "extent", for signature
> > "stand
> > Thankyou.
> >
> > Belay
> > On Sat, May 19, 2012 at 12:22 PM, Simon Knapp
> > wrote:
> >>
> >> provided you get the call to read.table (or perhaps read.csv) right
> >> and presuming that file contains only the image data, you should
> >> be able to say:
> >>
> >> r <- raster(as.matrix(read.csv("file.csv")))
> >> extent(r) <- extent(xmin, xmax, ymin, ymax)
> >>
> >> and not worry about the projection (if it is plain old decimal degrees)
> >>
> >> Regards,
> >> Simon
> >>
> >> On Sat, May 19, 2012 at 7:49 PM, Belay Gebregiorgis >
> >> wrote:
> >> > Hello everyone,
> >> >
> >> > I want to get a 1km by lkm grid raster image using my csv data. If I
> >> > call
> >> > latitude=a, longitude=b and preciptation=c.
> >> >
> >> > a<-(1,2,3,4,5)
> >> > b<-(6,7,8,9,10)
> >> > c<-(10,20, 30,40, 50)
> >> >
> >> > Then I found an example in r help which goes like
> >> >
> >> > pts = read.table("file.csv",..)
> >> > library(sp)
> >> > library(rgdal)
> >> >
> >> > proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
> >> > pts = spTransform(pts,CRS("insert your proj4 string here"))
> >> > gridded(pts) = TRUE
> >> > r = raster(pts)
> >> > projection(r) = CRS("insert your proj4 string here")
> >> >
> >> > Because I am new to R, I have no idea what to put into the proj4
> string
> >> > and
> >> > all that. Can anyone help me on this? If there is a different way of
> >> > doing
> >> > this, that is also fine.
> >> >
> >> > Kind Regards,
> >> >
> >> > Belay
> >> >
> >> >[[alternative HTML version deleted]]
> >> >
> >> > __
> >> > R-help@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.
> >
> >
>
[[alternative HTML version deleted]]
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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.
Re: [R] converting csv to image file
Thanks Simon. I have other vectors in the CSV file so after naming my
latitude and longitude x and y, I tried this. The first two lines run fine
but I get error in the second line.
r <- raster(as.matrix(F1))
extent(r) <- extent(xmin, xmax, ymin, ymax)
F1<-data.frame(x, y,z)
Error in function (classes, fdef, mtable) :
unable to find an inherited method for function "extent", for signature
"stand
Thankyou.
Belay
On Sat, May 19, 2012 at 12:22 PM, Simon Knapp wrote:
> provided you get the call to read.table (or perhaps read.csv) right
> and presuming that file contains only the image data, you should
> be able to say:
>
> r <- raster(as.matrix(read.csv("file.csv")))
> extent(r) <- extent(xmin, xmax, ymin, ymax)
>
> and not worry about the projection (if it is plain old decimal degrees)
>
> Regards,
> Simon
>
> On Sat, May 19, 2012 at 7:49 PM, Belay Gebregiorgis
> wrote:
> > Hello everyone,
> >
> > I want to get a 1km by lkm grid raster image using my csv data. If I call
> > latitude=a, longitude=b and preciptation=c.
> >
> > a<-(1,2,3,4,5)
> > b<-(6,7,8,9,10)
> > c<-(10,20, 30,40, 50)
> >
> > Then I found an example in r help which goes like
> >
> > pts = read.table("file.csv",..)
> > library(sp)
> > library(rgdal)
> >
> > proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
> > pts = spTransform(pts,CRS("insert your proj4 string here"))
> > gridded(pts) = TRUE
> > r = raster(pts)
> > projection(r) = CRS("insert your proj4 string here")
> >
> > Because I am new to R, I have no idea what to put into the proj4 string
> and
> > all that. Can anyone help me on this? If there is a different way of
> doing
> > this, that is also fine.
> >
> > Kind Regards,
> >
> > Belay
> >
> >[[alternative HTML version deleted]]
> >
> > __
> > R-help@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.
>
[[alternative HTML version deleted]]
__
R-help@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.
Re: [R] converting csv to image file
This already in your question:
"+init=epsg:4326"
That is equivalent to "+proj=longlat +ellps=WGS84" just looked up via the
EPSG code. A good site to explore this topic is spatialreference.org
On Saturday, May 19, 2012, Belay Gebregiorgis wrote:
> Hello everyone,
>
> I want to get a 1km by lkm grid raster image using my csv data. If I call
> latitude=a, longitude=b and preciptation=c.
>
> a<-(1,2,3,4,5)
> b<-(6,7,8,9,10)
> c<-(10,20, 30,40, 50)
>
> Then I found an example in r help which goes like
>
> pts = read.table("file.csv",..)
> library(sp)
> library(rgdal)
>
> proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
> pts = spTransform(pts,CRS("insert your proj4 string here"))
> gridded(pts) = TRUE
> r = raster(pts)
> projection(r) = CRS("insert your proj4 string here")
>
> Because I am new to R, I have no idea what to put into the proj4 string and
> all that. Can anyone help me on this? If there is a different way of doing
> this, that is also fine.
>
> Kind Regards,
>
> Belay
>
>[[alternative HTML version deleted]]
>
> __
> R-help@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.
>
--
Michael Sumner
Institute for Marine and Antarctic Studies, University of Tasmania
Hobart, Australia
e-mail: mdsum...@gmail.com
[[alternative HTML version deleted]]
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R-help@r-project.org mailing list
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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.
Re: [R] converting csv to image file
provided you get the call to read.table (or perhaps read.csv) right
and presuming that file contains only the image data, you should
be able to say:
r <- raster(as.matrix(read.csv("file.csv")))
extent(r) <- extent(xmin, xmax, ymin, ymax)
and not worry about the projection (if it is plain old decimal degrees)
Regards,
Simon
On Sat, May 19, 2012 at 7:49 PM, Belay Gebregiorgis wrote:
> Hello everyone,
>
> I want to get a 1km by lkm grid raster image using my csv data. If I call
> latitude=a, longitude=b and preciptation=c.
>
> a<-(1,2,3,4,5)
> b<-(6,7,8,9,10)
> c<-(10,20, 30,40, 50)
>
> Then I found an example in r help which goes like
>
> pts = read.table("file.csv",..)
> library(sp)
> library(rgdal)
>
> proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
> pts = spTransform(pts,CRS("insert your proj4 string here"))
> gridded(pts) = TRUE
> r = raster(pts)
> projection(r) = CRS("insert your proj4 string here")
>
> Because I am new to R, I have no idea what to put into the proj4 string and
> all that. Can anyone help me on this? If there is a different way of doing
> this, that is also fine.
>
> Kind Regards,
>
> Belay
>
> [[alternative HTML version deleted]]
>
> __
> R-help@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.
__
R-help@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.
[R] converting csv to image file
Hello everyone,
I want to get a 1km by lkm grid raster image using my csv data. If I call
latitude=a, longitude=b and preciptation=c.
a<-(1,2,3,4,5)
b<-(6,7,8,9,10)
c<-(10,20, 30,40, 50)
Then I found an example in r help which goes like
pts = read.table("file.csv",..)
library(sp)
library(rgdal)
proj4string(pts)=CRS("+init=epsg:4326") # set it to lat-long
pts = spTransform(pts,CRS("insert your proj4 string here"))
gridded(pts) = TRUE
r = raster(pts)
projection(r) = CRS("insert your proj4 string here")
Because I am new to R, I have no idea what to put into the proj4 string and
all that. Can anyone help me on this? If there is a different way of doing
this, that is also fine.
Kind Regards,
Belay
[[alternative HTML version deleted]]
__
R-help@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.
