无法使用tmap绘制普查区域

Question

我在用tmap绘制纽约的人口普查图时出错了。下面是一个例子和错误。

它要求API密钥是免费的。下面是链接- https://api.census.gov/data/key_signup.html

library(tidycensus)
library(tmap)

census_api_key("it requires API key")


NY <- get_acs(
  geography = "tract",
  table = "B19001",
  state = "NY", 
  year = 2020,
  geometry = TRUE,
  cache_table = TRUE
)

tm_shape(shp = NY) + 
  tm_polygons()

我搞错了。

Error in `$<-.data.frame`(`*tmp*`, "SHAPE_AREAS", value = c(5.02814518540036,  : 
  replacement has 91698 rows, data has 91987
In addition: Warning message:
The shape NY contains empty units. 

Answer 1

看起来get_acs()返回289个空几何图形，这会导致tmap错误。使用sf::st_make_valid可以处理错误，尽管它仍然会引起警告。

关于空几何图形的更多讨论，以及如何处理它们：https://r-spatial.org/r/2017/03/19/invalid.html#empty-geometries

NY <- get_acs(
  geography = "tract",
  table = "B19001",
  state = "NY", 
  year = 2020,
  geometry = TRUE,
  cache_table = TRUE
)

tm_shape(shp = st_make_valid(NY)) +  ### <- added st_make_valid here
  tm_polygons()

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