Overlaying ggmap , geom_polygon(shape file) on ggplot2

Question

I have a shape file, and I want to post it on top of a google map with ggplot, but posting via geom_polygon(ggplot2) shows lines that do not make sense

my code:

 ######## the shape file ftp://geoftp.ibge.gov.br/organizacao_do_territorio/malhas_territoriais/malhas_municipais/municipio_2015/Brasil/BR/
  download.file("ftp://geoftp.ibge.gov.br/organizacao_do_territorio/malhas_territoriais/malhas_municipais/municipio_2015/Brasil/BR/br_municipios.zip",temp)

data <- unz(temp, "BRMUE250GC_SIR.shp")

 data.shape<-st_read(data)


  ####### the map from ggmap
  mapa_edital_guarulhos <- get_map(location="GUARULHOS-SP",zoom=11,color = "bw",
                                   maptype = "roadmap") 


 mapa_edital_guarulhos_01<- ggmap(mapa_edital_guarulhos)

 ########## plotting with ggplot

 mapa_edital_guarulhos1 <- mapa_edital_guarulhos_01 + 
 geom_polygon(aes(x=long,y=lat, group=group), data=shape.sp, 
 color='black',alpha=0)

The result:

The arrow shows lines that do not make sense in my plot, plotting only the shape for the same interval:

plot(shape.sp,xlim=c(-47.25,-46.95),ylim=c(-23.1,-22.7))

whats is the problem in my code? thanks

List the source of that shapefile (and do not list the internal paths). Try to view only the shapefile, without the background to see if the lines remain. If so, remove the background. Isolate the problem. — LucasMation
Also, open the same file on qgis and check if the same lines show up there. — LucasMation

sebdalgarno sebdalgarno · Accepted Answer · 2018-05-05T02:16:43

Try using geom_sf rather than geom_polygon

first install dev version of ggplot2

devtools::install_github('tidyverse/ggplot2')

# read using sf instead of readOGR
library(sf)
# something like:
  data.shape <- st_read("www./BRMUE250GC_SIR.shp")

  ####### the map from ggmap
  mapa_edital_guarulhos <- get_map(location="GUARULHOS-SP",zoom=11,color = "bw",
                                   maptype = "roadmap") 


 mapa_edital_guarulhos_01<- ggmap(mapa_edital_guarulhos)

 ########## plotting with ggplot

 mapa_edital_guarulhos1 <- mapa_edital_guarulhos_01 + 
 geom_sf(data = data.shape, color = 'black', alpha=0)

It's hard to test this without having the dataset. But let me know if that works! I have seen this resolve the problem you are having before.

Overlaying ggmap , geom_polygon(shape file) on ggplot2

1 Answers