[R] Producing plot using polygon function

[Uwe Ligges]

On 19.11.2011 20:19, avinash barnwal wrote:
> Hi,
>
> Thanks for realizing my mistakes
> Sorry for the typo mistakes, first i m storing the array then doing the
> operations. But that is not my issue, i m suppose to fill the area of plot
> wherever a2>a3 . May be through polygon it would be tough to complete .
> Looking for some hep through ggplot2


ggplot2 may be a nice package, but it won't help if you do not 
understand the underlying issues. Your code is too incomplete so that we 
cannot fix it. Better think about how you would draw a polygon manually 
and what you did in R.

And note that in

polygon(c(time[1:j],time[1:j]),c(x,y),col="grey")

Your time vector does not fit to x nor y (and you probably want to 
reverse the second entries in each c() call.

Uwe Ligges




>
> 2011/11/19 Uwe Ligges<ligges at statistik.tu-dortmund.de>
>
>>
>>
>> On 18.11.2011 23:48, avinash barnwal wrote:
>>
>>> Hi,
>>>
>>> I am looking forward to fill the plot using conditions on variables a2 and
>>> a3. Whenever variable(a2) goes above variable(a3) i fill it with some
>>> color
>>> .
>>>
>>> I am storing the coordinates of a2 and a3 in x and y as well as time where
>>> it is occurring . But it is not producing properly. I must be wrong
>>> in assigning  coordinates.
>>> What should be the correct way to produce the desired plot?
>>>
>>> Thanks in advance
>>> ##############################**##############################**
>>> ##############################**############
>>> x<-vector()
>>> y<-vector()
>>> temp_time<-vector()
>>>
>>
>> Defining *empty* vectors is almost never what you really want to do.
>>
>>   for(i in 1:length)
>>>
>>
>> Running a loop 1:length is dangerous if a length is<  1, run it
>> seq_along(.).
>>
>>
>>   {
>>> if(a2[i]>a3[i])
>>> {
>>> j<-j+1
>>> x[j]<-a2[i]
>>> y[j]<-a3[j]
>>>
>>
>> You meant a3[i], I guess.
>>
>>   temp_time<-time[i]
>>> }
>>> }
>>>
>>
>> At the end of this loop, this obviously simplifies to:
>>
>> l<- a2>  a3
>> x<- a2[l]
>> y<- a3[l]
>> temp_time<- time[length]
>>
>>
>>
>>   time<-q[,1]
>>> a2<-q[,3]
>>> a3<-q[,4]
>>> plot(time,a2type='l',col='red'**,ylab='',xlab=" ",axes=FALSE)
>>> lines(time,a3,col='blue',ylab=**'',xlab=" ")
>>> polygon(c(time[1:j],time[1:j])**,c(x,y),col="grey")
>>>
>>
>> Since you don't use anything from inside your loop here, why do you run
>> that at all? Is this homework?
>>
>> Uwe Ligges
>>
>
>
>