R小册子中重叠多边形的标签-Java 学习之路

我需要标记几个重叠的多边形，但只显示最大的多边形标签 . 但是，当我使用一些模拟数据进行测试时，标签显示正确 . 我仔细比较了两个案例中的数据，但找不到造成问题的区别 .

以下是模拟重叠多边形的最小示例：

library(leaflet)
library(sp)

poly_a <- data.frame(lng = c(0, 0.5, 2, 3),
                     lat = c(0, 4, 4, 0))
poly_b <- data.frame(lng = c(1, 1.5, 1.8),
                     lat = c(2, 3, 2))
pgons = list(
  Polygons(list(Polygon(poly_a)), ID="1"),
  Polygons(list(Polygon(poly_b)), ID="2")
)
poly_dat <- data.frame(name = as.factor(c("a", "b")))
rownames(poly_dat) <- c("1", "2")

spgons = SpatialPolygons(pgons)
spgonsdf = SpatialPolygonsDataFrame(spgons, poly_dat, TRUE)

leaflet() %>% addPolygons(data = spgonsdf, label = ~name
                          #           ,
                          #           highlightOptions = highlightOptions(
                          # color = "red", weight = 2,bringToFront = TRUE)
)

它运作正常：

enter image description here

但它不适用于我的数据 .

https://github.com/rstudio/leaflet/files/1430888/Gabs.zip

您可以将拉链拖动到this site并使用i按钮查看它是否已正确标记

enter image description here

library(rgdal)

# download Gabs.zip and extract files to Gabs folder
hr_shape_gabs <- readOGR(dsn = 'Gabs', layer = 'Gabs - OU anisotropic')
hr_shape_gabs_pro <- spTransform(hr_shape_gabs, 
                                 CRS("+proj=longlat +datum=WGS84 +no_defs"))
leaflet(hr_shape_gabs_pro) %>%
  addTiles() %>% 
  addPolygons(weight = 1, label = ~name)

仅显示最大的多边形标签：

enter image description here

两种情况下的数据都是SpatialPolygonsDataFrame，数据槽具有正确的多边形名称 .

1 回答

更改 hr_shape_gabs 中多边形的顺序：位置3中的多边形应该是较小的多边形 .

library(leaflet)
library(sp)
library(rgdal)
hr_shape_gabs <- readOGR(dsn = 'Gabs - OU anisotropic.shp', 
                         layer = 'Gabs - OU anisotropic')

# Change the position of the smaller and wider polygons
# Position 1 = wider polygon, position 3 = smaller polygon
pol3 <- hr_shape_gabs@polygons[[3]]
hr_shape_gabs@polygons[[3]] <- hr_shape_gabs@polygons[[1]]
hr_shape_gabs@polygons[[1]] <- pol3
hr_shape_gabs$name <- rev(hr_shape_gabs$name)

hr_shape_gabs_pro <- spTransform(hr_shape_gabs, 
                                 CRS("+proj=longlat +datum=WGS84 +no_defs"))
leaflet() %>%
  addTiles() %>% 
  addPolygons(data= hr_shape_gabs_pro, weight = 1, label = ~name)

enter image description here

回复于 2024-04-25T19:26:09+08:00

R小册子中重叠多边形的标签

1 回答

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