堆积条形图中错误顺序的1条（R ggplot2）

Question

我制作了一个堆积条形图，但第三个条形图的分段顺序不同;应位于底部的片段现在位于顶部，请参见图像：

当我改变x轴的顺序时，它与第3个条完全相同。我怎么解决这个问题？代码出了什么问题？

library('ggplot2')
bar <- ggplot(data.location, aes(Location, value, fill=variable))
bar + stat_summary(fun.y=mean, geom="bar", position="stack")+labs(x="Location", y="value", fill="variable")

补充：dput（data.location）的输出

dput(data.location[data.location$Location %in% c('BRM', 'CG', 'DDO'),])

structure(list(Location = structure(c(2L, 3L, 5L, 2L, 3L, 5L, 
2L, 3L, 5L, 2L, 3L, 5L), .Label = c("BA", "BRM", "CG", "CH", 
"DDO", "DR", "FB", "GG", "GI", "GQS", "HC", "HS", "LL1", "LL2", 
"MOW", "PP", "TP", "TR", "TRD", "WB"), class = "factor"), Zone = c(1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), variable = structure(c(1L, 
1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L), .Label = c("A", "B", "C", "D"
), class = "factor"), value = c(425.810194245673, 815.265455416096, 
735.274721619422, 997.041922511793, 2147.03610300279, 1210.08829970945, 
0, 177.692085889937, 173.266014794846, 406.498315338813, 1293.35105648741, 
234.022025228589)), .Names = c("Location", "Zone", "variable", 
"value"), row.names = c(2L, 3L, 5L, 22L, 23L, 25L, 42L, 43L, 
45L, 62L, 63L, 65L), class = "data.frame")​

Answer 1

使用以下代码，我得到了一致的条形顺序。

ggplot(data.location,aes(Location,value,fill=variable,order=variable))+
geom_bar(stat="identity")