Qué necesito

Paquetes de R

x <- c("sf","ggplot2","cowplot","rcartocolor","broom","rgdal","tidyverse")

lapply(x, library, character.only = TRUE) # carga los paquetes requeridos

Mapa de la zona del contexto

rutamc<-"D:/Documents/Claudia/Midropbox/Investigacion y escritos/mapasnacionales"


ylim=c(25.47, 25.67)
xlim=c(-103.30, -103.52)


tormun <- readOGR(rutamc,"torageb", use_iconv = TRUE, encoding = "latin1")
## OGR data source with driver: ESRI Shapefile 
## Source: "D:\Documents\Claudia\Midropbox\Investigacion y escritos\mapasnacionales", layer: "torageb"
## with 332 features
## It has 5 fields
# Para poder graficar con ggplot se convierte en una tabla (dataframe) (paquete broom)
tormun$id <- rownames(tormun@data)
tormun_df <- tidy(tormun, region = "id")
# Se agrega un identificador al shapefile que corresponderá al número de renglón


# Se reunen los dos archivos a partir del id
tormun_df <- left_join(tormun_df,tormun@data,by = "id")

Mapa de la zona encuadrada y sus límites en rectángulo

tormunpzo <- readOGR(rutamc,"cropped_muntorsp", use_iconv = TRUE, encoding = "latin1")
## OGR data source with driver: ESRI Shapefile 
## Source: "D:\Documents\Claudia\Midropbox\Investigacion y escritos\mapasnacionales", layer: "cropped_muntorsp"
## with 3060 features
## It has 11 fields
#límites del pedazo 
tormunpzo_bb = st_as_sfc(st_bbox(tormunpzo))

Mapas separados y mapa subordinado con la función draw_plot

mapgde = ggplot() + 
  geom_path(data = tormun_df,aes(x = long, y = lat, group = group), fill = "white") + 
  geom_sf(data = tormunpzo_bb, fill = NA, color = "red", size = 1.2) +
  theme_void()
mapgde

zonarec = ggplot() + 
  geom_path(data = tormunpzo,aes(x = long, y = lat, group = group, fill = "white"))+
  theme_void() 
zonarec

map_inset = ggdraw() +
  draw_plot(zonarec, x = 0.0, y = 0, width = 0.85, height = 1) +
  draw_plot(mapgde, x = 0.75, y = 0.7, width = 0.3, height = 0.3)
map_inset

Procedimiento con un polígono como marco

rutamc<-"D:/Documents/Claudia/Midropbox/Investigacion y escritos/mapasnacionales"

tormunc <- readOGR(rutamc,"muntor", use_iconv = TRUE, encoding = "latin1")
## OGR data source with driver: ESRI Shapefile 
## Source: "D:\Documents\Claudia\Midropbox\Investigacion y escritos\mapasnacionales", layer: "muntor"
## with 36105 features
## It has 11 fields
rutacam<-"D:/Documents/Claudia/Midropbox/Investigacion y escritos/mapasnacionales/"

limitesbox<-read.csv(paste0(rutacam,"limites.txt"),header=TRUE, sep=",",encoding="latin")
names(limitesbox)<-c("long","lat")

#Crear el polígono

p = Polygon(limitesbox)
ps = Polygons(list(p),1)
sps = SpatialPolygons(list(ps))

sps_bb<-st_as_sfc(sps)

mapgde = ggplot() + 
  geom_path(data = tormun_df,aes(x = long, y = lat, group = group)) + 
  geom_sf(data = sps_bb, fill=NA,color = "red", size = 1.2) +
  theme_void()
mapgde

#proj4string(sps)
#proj4string(tormun)
sp::proj4string(sps) <- CRS("+proj=longlat +datum=WGS84 +no_defs")

muninsps <- tormunc[sps, ]

zonarec = ggplot() + 
  geom_path(data = muninsps,aes(x = long, y = lat, group = group, fill = "white"))+
  theme_void() 
zonarec

map_inset = ggdraw() +
  draw_plot(zonarec, x = 0.0, y = 0, width = 1, height = 1) +
  draw_plot(mapgde, x = 0.75, y = 0.7, width = 0.3, height = 0.3)
map_inset

ggsave("inset_map.png", width = 1300, height = 1300, units = "mm", dpi = "retina",limitsize = FALSE)