识别空间点是否在空间多边形中

Question

here my R code link about coords of municipalita dataset with coords of stops

I have a problem with my R code, because I have a error and I don't know how fix it.

I have 2 datasets:

1. a network of bus stops of a city (I have longitude and latitude for every stops) and I import the dataset st_as_sf .
2. township of the city. I have imported the shapefile with the sf library---the same format as the stops dataset.

The I'm getting is :

Error in st_geos_binop("intersects", x, y, sparse = sparse, prepared = prepared, : st_crs(x) == st_crs(y) is not TRUE

And here is my code:

# MUNICIPALITA --------------
library("rgdal")
library("raster")
library("sf")


#in questo file provo  leggere con la libreria sp e non sf i file shape
#f=system.file("C:/Users/CELESTE/Desktop/ambiti_amm/A_SCOM.shp",package = "sf")

municipalita=shapefile("C:/Users/CELESTE/Desktop/ambiti_amm/A_SCOM.shp")
municipalita_df=as.data.frame(municipalita)
municipalita_df=municipalita_df[,-c(3:5,8:20)]


point.in.polygon()


municipalita_sf=st_as_sf(municipalita, crs = 4326)
municipalita_sp=as_Spatial(municipalita_sf)


class(municipalita)


municipalita$SCOM_COD=as.numeric(municipalita$SCOM_COD)
municipalita$A_SCOM_TY=as.numeric(municipalita$A_SCOM_TY)


municipalita=subset(municipalita,municipalita[,1]==6)
m=as.data.frame(m)

municipalita=municipalita[,-1]
municipalita=municipalita[-c(2,3,5,7:9),]

m=st_as_sf(municipalita)


mappa_municipalita=mapview(m)
mappa_municipalita

colnames(m)[1]="Quartieri"
colnames(m)[2]="ID_quartiere"
colnames(m)[3]="ID_municipalita"

mapview(m, zcol = "Quartieri") 
mapview(m,zcol="ID_quartiere")
mapview(m,zcol="ID_municipalita")

colnames(m$)



class(valori_unici_sp)

##########################
install.packages("spatialEco")
library("spatialEco")
pip=point.in.poly(valori_unici_sp,municipalita_sp)

Answer 1

It is hard to be 100% certain without having access to your data, but it seems that you did not assign a CRS to your valori_unici_sp object (or if you did it was not EPSG:4326 like with your shapefile).

Note that:

• when doing point-in-polygon operation both objects need to be in the same CRS - in my case 4326, but any would do as long as it is the same for both objects; this mismatch is the root cause of your issue
• I suggest you use sf::st_join() to link the points to polygons, with setting left = FALSE , meaning the join operation will not be one sided (left join in SQL speak) but filtering (inner join in SQL speak)

For a reproducible example addressing your use case consider this code; it uses the nc.shp shapefile (available in all {sf} installations) and three semi random North Carolina cities. It then links the cites to the shapefile to get county data.

library(sf)

# included with sf package
shape <- st_read(system.file("shape/nc.shp", package="sf")) %>%  
    st_transform(4326)

# three semi random cities
cities <- data.frame(name = c("Raleigh", "Greensboro", "Wilmington"),
                  x = c(-78.633333, -79.819444, -77.912222),
                  y = c(35.766667, 36.08, 34.223333)) %>% 
  st_as_sf(coords = c("x", "y"), crs = 4326)

# the action is here!
result <- st_join(cities, shape, left = F)

# check the structure of outcome
result
Simple feature collection with 3 features and 15 fields
geometry type:  POINT
dimension:      XY
bbox:           xmin: -79.81944 ymin: 34.22333 xmax: -77.91222 ymax: 36.08
geographic CRS: WGS 84
        name  AREA PERIMETER CNTY_ CNTY_ID        NAME  FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79
1    Raleigh 0.219     2.130  1938    1938        Wake 37183  37183       92 14484    16    4397 20857    31
2 Greensboro 0.170     1.680  1903    1903    Guilford 37081  37081       41 16184    23    5483 20543    38
3 Wilmington 0.042     0.999  2238    2238 New Hanover 37129  37129       65  5526    12    1633  6917     9
  NWBIR79                   geometry
1    6221 POINT (-78.63333 35.76667)
2    7089    POINT (-79.81944 36.08)
3    2100 POINT (-77.91222 34.22333)