[R-sig-Geo] Reading an Ascii file

[van Etten, Jacob (IRRI)]

The case for a as.data.frame(signature=RasterStack) method (then you
would have three lines (one less than Kamran)

-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch
[mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of Kamran Safi
Sent: Thursday, January 15, 2009 3:28 PM
To: Robert Hijmans; Juliane Struve
Cc: R-sig-Geo at stat.math.ethz.ch
Subject: Re: [R-sig-Geo] Reading an Ascii file

Hi all,

This should deliver the results Julie is looking for:

library(rgdal)
library(maptools)
grid <- readAsciiGrid("<your file and its path>")
table <- data.frame(grid)

That was it! Replace s1 and s2 with X and Y.

Kamran



------------------------
Kamran Safi

Postdoctoral Research Fellow
Institute of Zoology
Zoological Society of London
Regent's Park
London NW1 4RY

http://www.zoo.cam.ac.uk/ioz/people/safi.htm

http://spatialr.googlepages.com
http://asapi.wetpaint.com



-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch on behalf of Robert Hijmans
Sent: Thu 15.01.2009 03:13
To: Juliane Struve
Cc: R-sig-Geo at stat.math.ethz.ch
Subject: Re: [R-sig-Geo] Reading an Ascii file
 
Dear Julie,

This is one way to do that, using the raster package (under
development):


install.packages("raster",
repos="http://R-Forge.R-project.org<http://r-forge.r-project.org/>
")

require(raster)
r <- rasterFromFile("d:/alt.asc", TRUE)
xy <- xyFromCell(r, 1:ncells(r))
xyv <- cbind(xy, values(r))

xyv[1:10,]

# To get rid of the NAs

xyv <- na.omit(xyv)
xyv[1:10,]




On Thu, Jan 15, 2009 at 1:01 AM, Juliane Struve
<juliane_struve at yahoo.co.uk>wrote:

> Dear list,
>
> I am trying to read ArcGIS raster data sets into R after converting
them
> into ASCII .txt file. The text file I am trying to read contains
>
> ncols         250
> nrows         276
> xllcorner     344147.19411119
> yllcorner     3024657.6122834
> cellsize      0.19970250725746
> NODATA_value  -9999
>
> in the first lines followed by a grid of values that are either -9999
or 1.
>
> I have used read.table("myfile.txt") which yields this (first 10
lines).
>
>
> V1            V2
> 1          ncols  2.500000e+02
> 2          nrows  2.760000e+02
> 3      xllcorner  3.441472e+05
> 4      yllcorner  3.024658e+06
> 5       cellsize  1.997025e-01
> 6      NODATA_value -9.999000e+03
> 7          -9999 -9.999000e+03
> 8          -9999 -9.999000e+03
> 9          -9999 -9.999000e+03
> 10        -9999 -9.999000e+03
>
> I would like to have the data as a table with coordinates for each
cell and
> the actual value.
>
> Could somebody advise me which function I should use ?
>
> Many thanks,
>
> Juliane
>
>
>
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

	[[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo




Click https://www.mailcontrol.com/sr/wQw0zmjPoHdJTZGyOCrrhg==  to report
this email as spam.



The Zoological Society of London is incorporated by Royal Charter
Principal Office England. Company Number RC000749
Registered address: 
Regent's Park, London, England NW1 4RY
Registered Charity in England and Wales no. 208728 

________________________________________________________________________
_
This e-mail has been sent in confidence to the named\ ad...{{dropped:8}}