[Raster-commits] r485 - pkg/raster/R

[noreply at r-forge.r-project.org]

Author: sonia
Date: 2009-09-10 04:03:44 +0200 (Thu, 10 Sep 2009)
New Revision: 485

Added:
   pkg/raster/R/trmm3B43ToRaster.R
Log:
added a function for converting TRMM 3B43 v6 data downloaded from NASA's TRMM TOVAS website


Added: pkg/raster/R/trmm3B43ToRaster.R
===================================================================
--- pkg/raster/R/trmm3B43ToRaster.R	                        (rev 0)
+++ pkg/raster/R/trmm3B43ToRaster.R	2009-09-10 02:03:44 UTC (rev 485)
@@ -0,0 +1,37 @@
+# Author: Angelo Carlo D. PAcheco and Jorrel  Khalil Aunario
+# Date : September 9, 2009
+# Version 0.1
+# Licence GPL v3
+
+
+library(raster)
+
+# Function for converting TRMM 3B43 v6 ascii data to raster 
+#  Indicate the number of header lines to remove (except column names)
+asciiToRaster<- function(filename, outputFName="trmm.tif", hdrs=5){
+
+
+	write.table(readLines(filename)[-(1:hdrs)], "temp.txt", row.names=F, col.names=F, quote=F)
+	coor <- read.table("temp.txt", header=T)
+
+	y = max(coor[,1]) - min(coor[,1]) 
+	y = y*4
+
+	x = max(coor[,2]) - min(coor[,2]) 
+	x = x*4
+
+	rast <- raster(nrow=y, ncol=x, xmn=min(coor[,2]), xmx=max(coor[,2]), ymn=min(coor[,1]), ymx=max(coor[,1]) )
+	rast[] <- -9999
+
+	vec <- 1:length(rast[])
+	vec[] <- -9999
+
+	c <- cellFromXY(rast, cbind(coor[,2],coor[,1]) )
+	vec[c] <- coor[,3]
+
+	rast <- setValues(rast, vec)
+
+	filename(rast) <- outputFName
+	writeRaster(rast, file="GTiff")
+
+}
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