RWBP (version 1.0)

predict.RWBP: predict.RWBP

Description

Predict spatial outliers according to a RWBP model

Usage

"predict"(object, top_k = 3, type = "raw", ...)

Arguments

object

a RWBP object

top_k

the number of outliers to extract

type

"raw" returns classification results (0 for normal, 1 for outlier). "prob" returns probabilities for being outlier.

...

currently not in use

Value

Returns the input data frame/matrix with an additional column that contains the prediction results. The additional column is set according to the type parameter:

raw

"class" column is added

prob

"prob" column is added

References

Liu X., Lu C.T., Chen F.: Spatial outlier detection: Random walk based approaches. In: Proceedings of the 18th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM GIS), San Jose, CA (2010).

See Also

RWBP,RWBP-package

Examples

#an example dataset:
trainSet <- cbind(
c(7.092073,7.092631,7.09263,7.093052,7.092876,7.092689,7.092515,7.092321,
7.092138,7.11455,7.11441,7.11408,7.11376,7.11338,7.11305,7.11277,7.1124,
7.11202,7.11161,7.11115,7.11068,7.11014,7.10963,7.1095,7.1089,7.10818,
7.10747,7.10674,7.116691,7.116142,7.115559,7.115007,7.114423,7.113838,
7.113272,7.112684,7.112067,7.111458,7.110869,7.110274,7.109696,7.109131,
7.109231,7.108546,7.10797,5.599215,5.597609,5.596588,5.595359,5.594478,5.593652),
c(50.77849,50.77859,50.7786,50.77878,50.77914,50.77952,50.77992,50.78035,
50.78081,53.8,53.7,53.6,53.5,54.2,55.3,55.2,56.6,57.6,57.7,58.8,59.4,59.7,
59,59.03,59.3,60.7,60.8,61.4,50.73922,50.73914,50.73905,50.73899,50.73889,
50.73881,50.73873,50.73865,50.73856,50.73847,50.73838,50.73831,50.73822,
50.73814,50.73937,50.73805,50.73798,43.2034,43.20338,43.20352,43.2037,43.20391,43.20409),
c(106.5,107.6,25,108.5,109.1,109.7,111.6,113.3,113.3,62.3,333.7,331.5,327.2,
325.5,324.8,323.5,322.3,320.3,319,317.8,316,315.1,315.3,12,312.4,311.3,310.8,
309.4,99.2,99.2,101.1,99.5,101.3,105.3,104.3,104.4,106.3,108.8,110.3,111.7,113.3,
112.1,5000,111.6,109.8,125.6,130,132.3,133.4,138,143.4),
c(0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,1,0,0,0,0,0,0,0,0)
)

colnames(trainSet)<- c("lng","lat","alt","isOutlier")

#first to columns of the input data are assumed to be spatial coordinates, 
#and the rest are non-spatial attributes according to which outliers will be extracted
myRW <- RWBP(as.data.frame(trainSet[,1:3]), clusters.iterations=6)

#predict classification:
testPrediction<-predict(myRW,3 )
#calculate accuracy:
sum(testPrediction$class==trainSet[,"isOutlier"])/nrow(trainSet)
#confusion table
table(testPrediction$class, trainSet[,"isOutlier"])

#other options:
myRW1 <- RWBP(isOutlier~lng+lat+alt, data=as.data.frame(trainSet))
#print model summary
print(myRW1)
#plot model graph
plot(myRW1)
#predict probabilities of each record to be an outlier:
predict(myRW1 , top_k=4,type="prob")