[R] Grid lines

[Uwe Ligges]

Chris Li wrote:
> Thanks for the reply guys. Below are the script and data files.
> 
> http://www.nabble.com/file/p24734049/HEAD_calibration.R HEAD_calibration.R 
> http://www.nabble.com/file/p24734049/6527-1052 6527-1052 
> http://www.nabble.com/file/p24734049/6527-1054 6527-1054 
> http://www.nabble.com/file/p24734049/MAR3 MAR3 
> 
> Once again, thank you for your help, greatly appreciated!!
> 
> Chris
> 
> 
> Chris Li wrote:
>> Hi everyone. I am new to R.
>>
>> It will be greatly appreciated if someone can help me with the following
>> questions.
>>
>> Here's the graph I have just produced. 
>> http://www.nabble.com/file/p24732839/calibration.jpeg 
>>
>> (1) How can I put the legend on top of the grid lines?
>>
>> (2) How can I match the grid lines with the x-axis ticks?
>>
>> (3) How can I change the x-axis format from e.g. Mar, Apr...etc to
>> 1-3-2009,1-4-2009...etc?
>>
>> Many thanks! :-)
>>
>> Chris
>>
> 


Example for your loop:

for (i in c(1:n)){
     file.name=f[i]
     dat<-read.csv(file.name,header=F)
     colnames(dat)<-c("obsTime","obsHead","comTime","comHead")
     obsTime<-as.Date(dat$obsTime,origin=model.startdate)
     comTime<-as.Date(dat$comTime,origin=model.startdate)

### omit x axis at first:
     plot(obsTime,dat$obsHead,main=file.name,xlab="Date",ylab="Hydraulic 
Head (mAHD)",col="blue",ylim=c(ymin,ymax), xaxt="n")

### add x axis with given format and save the locations:first:
     xticks <- axis.Date(1, obsTime, format = "%d-%m-%Y")
     lines(comTime,dat$comHead,col="red")

### add you self designed grid:
     abline(v=xticks, h=axTicks(2), lty=1, col="darkgray")

### legend with white background at the end:
     legend("bottomright",legend=c("Observed Head","Computed 
Head"),col=c("blue","red"),lty=c(0,1),pch=c(1,-1), bg="white")


### forget about:
#    grid(lty=1,col="darkgray")
}



Uwe Ligges