[R-sig-Geo] problem to module MERGE GRID in RSAGA

[Tomislav Hengl]

> -----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 gianni lavaredo
> Sent: Tuesday, April 07, 2009 4:44 PM
> To: r-sig-geo at stat.math.ethz.ch
> Subject: [R-sig-Geo] problem to module MERGE GRID in RSAGA
> 
> Dear R Users
> 
> I have a problem to understand the loop merge in RSAGA
> 
> I have this file (not order name)
> DEM2644147
> DEM2644148
> DEM2644149
> DEM2744150
> DEM2744155
> DEM2744168
> 
> I did a file list in CSV:
> 
> path<- ("C:/mydata/")
> temp  <- paste(path,"input.csv", sep="")
> input  <- read.csv(temp, header = TRUE)
> attach(input)
> names(input)
> temp <- file
> file.list <- as.list(temp)
> 
> 
> # USE POWER TO DEM
> power <- seq(1.0, 10.0, by=0.1)
> 
> # power of DCM
> for(i in 1:length(file.list)){
> for (method in 1:length(power)){
>       rsaga.grid.calculus(in.grids = c(paste("C:/mydata/DEM",
> file.list[[i]],".sgrd", sep="")),
>            out.grid =
> c(paste("C:/mydata/Power_DEM",file.list[[i]],"_",method+9,".sgrd",sep="")),
>            formula = paste("a^",power[method],sep=""))
> }
> }
> 
> #TRY with two DEM with power^1
> rsaga.geoprocessor(lib="grid_tools", module=3,
> param=list(GRIDS="C:/mydata/Power_DEM2644147_10.sgrd;C:/mydata/Power_DEM2644148_10.sgrd",
> MERGED="C:/mydata/merge_power10.sgrd",TYPE=6,INTERPOL=0,OVERLAP=0))
> 
> Now I am trying to merge in a LOOP every DEM to have:
> all_merge_power10
> all_merge_power11
> all_merge_power12
> all_merge_power13
> etc
> 
> 
> for(i in 1:length(file.list)){
> for (method in 1:length(power)){
> rsaga.geoprocessor(lib="grid_tools", module=3,
>    param=list(GRIDS=c(paste("C:/mydata/Power_DEM",file.list[[i]],"method+9",".sgrd",sep="")),
>    MERGED="C:/mydata/all_merge_power10.sgrd",
>    TYPE=6,
>    INTERPOL=0,
>    OVERLAP=0))
> }
> }

why do you loop?

simly do:

> GRIDS=paste(set.file.extension(file.list, ".sgrd"), collapse=";")

There is also no need to write the working directory every time. Just set it up at the beginning:

> setwd("C:/mydata/")

Some similar examples here:

http://spatial-analyst.net/wiki/index.php?title=Software#SAGA_GIS

T. Hengl

> 
> 
> 
> I have diffucult to load all DEM power 10, ect etc and every time I have a
> Error :-(.
> 
> Thanks a lot
> 
> Gianni
> 
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