r 在点上绘制多边形并导出到ESRI Shapefile

Posted 2021-05-23

draw.polygon <- function(xy.records,export) {
  
  library(spatstat)

    plot(xy.records,col="gray",pch=20)
    
    poly <- clickpoly(add=TRUE)
    
    p = Polygon(cbind(poly$bdry[[1]]$x,poly$bdry[[1]]$y))
    ps = Polygons(list(p),1)
    sps = SpatialPolygons(list(ps))
    plot(sps,add=TRUE,col="#727272")
    points(xy.records,col="red",pch=20)
    
    crs(sps) <- "+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0" 
    sps <- as(sps, "SpatialPolygons")
    
    if(export) { writeOGR(as(sps, "SpatialPolygonsDataFrame"), "", "polygon", driver="ESRI Shapefile",overwrite_layer=TRUE) }
    
  return( sps )
  
}

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