raster::erase 函数 - RGEOSBinTopoFunc 中的错误：TopologyException

Question

根据我之前的帖子解决方案，我正在使用光栅包擦除功能来裁剪和溶解重叠的多边形 - Dissolve Overlapping Polygons using difference and union in R

对于某些多边形，我使用擦除功能遇到错误：

RGEOSBinTopoFunc 中的错误（spgeom1，spgeom2，byid，id，drop_lower_td，unaryUnion_if_byid_false，： TopologyException：输入几何 1 无效：在点 1.1197332302192855 47.203098020153668 处或附近自交点 1.1197332302192855 47.203098020153668

library(raster)
library(rgeos)
library(sp)

fields <- gBuffer(fields, byid=TRUE, width=0) # Expands the given geometry to include 
the area within the specified width 

zone <- fields[fields$Type == "Zone", ]
plot <- fields[fields$Type == "Plot", ]

d <- erase(zone, plot) #issue here
spplot(d, "Rx")

# I tried using rgeos::gBuffer to avoid RGEOSBinTopology Exception but it did not worked out. Any guidance in this area would be really helpful.

zone <- gBuffer(zone, byid=TRUE, width=0)
plot <- gBuffer(plot, byid=TRUE, width=0)

Answer 1

绘图多边形真的很乱。即使它们是有效的。 erase 中出现的问题变成它聚合（“dissolves”）参数y（“fields”），但会生成无效的拓扑。我需要研究如何最好地捕捉它，但是，现在（也许有一段时间），这里有一个使用 cleangeo 的解决方法，但你可能想要使用一个工具来清理字段多边形（捕捉顶点） - -- 或许使用 Rmapshaper？

library(raster)
library(rgeos)

f <- "WUERZ-I-WW _ Plot _TrialMap.shp"
fields = shapefile(f)
zone <- fields[fields$Type == "Zone", ]
plot <- fields[fields$Type == "Plot", ]

aplot <- aggregate(plot)
rgeos::gIsValid(aplot)
#[1] FALSE
#Warning message:
#In RGEOSUnaryPredFunc(spgeom, byid, "rgeos_isvalid") :
#  Self-intersection at or near point 13.033265979999999 51.190776640000003

library(cleangeo)
cplot <- clgeo_Clean(aplot)
rgeos::gIsValid(cplot)
# TRUE

d <- erase(zone, cplot)