ARIMA forecasting - Avoid negative preditions

[141507]

Hi,

I am using below R code to generate Arima Forecast. The plot is successful and I dont want to see negative values in the plot. I used the lambda=0 in the arima() and my plot date is greater than zero records only. Still I am seeing negative predicions.

.

Is there anyway to prevent this. Below is my R code.

library(xts)
library("forecast")
dates=as.Date(dataset$ReceivedDate,"%Y-%m-%d")
xs=xts(dataset$Volume,dates,frequency=12)
plot(xs)

arima1 <-arima(xs,order=c(2,1,5),seasonal=list(order=c(0,1,1),period=12,lambda=0))
q=forecast(arima1,h=60,level=c(99.5))
plot(q,col ="darkcyan",xaxt = 'n',xlab='Year', ylab = 'Volume',main='Inventory Forecast (Arima)')
axis(side=1,at=c(0,50,100,150,200),labels=c("Aug 2016","Oct 2016","Dec 2016","Jan 2017","Mar 2017"))
 
file.remove("D:/fitarima.csv")
write.table(q,file="D:/fitarima.csv", append=TRUE,sep=",",col.names=TRUE,row.names=TRUE)

Regards,

Senthil D

[v-ljerr-msft]

Hi @141507,

Here is an article about positive forecasts and forecasts constrained to an interval. Could you go to check if it helps in your scenario? 

Regards

[141507]

Hi,

Thanks for your input, But using this, prediction line shows as constant.

Do We have any other way to achieve the positive prediction since we have positive values as resource data ?

Regards,

Senthil D

[141507]

Hi,

Is any update for the above.

Regards,

Senthil D