This code provide a way to read in IDRISI Raster Format with terra and plot with ggplot2

terra-idrisi-raster-plot.R

library(terra) # Spatial Data Analysis
library(tidyterra) # 'tidyverse' Methods and 'ggplot2' Helpers for 'terra' 
library(ggplot2) # For  Data Visualisations Using the Grammar of Graphics
library(rgeoboundaries) # For Political Administrative Boundaries
library(ggspatial) # Spatial Data Framework for ggplot2 
library(ggtext) # Improved Text Rendering Support for 'ggplot2'
library(ggsflabel) # for spatial labeling

x <- terra::rast(x = "/Volumes/OUSMANE/exo_BSD/semis_fin_07/sem0173.rst")
y <- classify(x,c(0,1,2,3,4,5,6,7,8)) 

ne_adm1 <- geoboundaries(country = "Niger",adm_lvl = 1)# need internet
ne_adm0 <- geoboundaries(country = "Niger",adm_lvl = 0)
ggplot()+geom_spatraster(data = y)+geom_sf(data = ne_adm1,fill=NA)+
  geom_sf(data = ne_adm0,fill=NA,linewidth=1)+
  geom_sf_label_repel(data = ne_adm1,aes(label = shapeName))+
  scale_fill_viridis_d("Légende",
                       na.value = NA,
                       labels = c(paste("date",1:7),"No data")
                       )+
  labs(title = "Date de semis optimales à la décade  de Juillet 2001",
       subtitle = "Sortie de simulation DHC-CP",
       caption ="© 2023 - **Ousmane Ouedraogo**, _oousmane.github.io_",
       x = "Longitude (°)",
       y = "Latitude (°)")+
  scale_x_continuous(limits = c(0,16),breaks = seq(0,16,2))+
  theme_classic(base_size = 14)+
  theme(legend.key = element_rect(color = "black"),
        legend.background = element_rect(color = "black"),
        plot.title = element_text(face = "bold"),
        plot.caption = element_markdown(),
        panel.grid.major = element_line(linetype = "dashed",color ="grey"),
        panel.background = element_rect(fill = "gray90")
        )+
  annotation_north_arrow(style = north_arrow_nautical(),
                         location = "tl")+
  annotation_scale(text_face = "bold
                   ",location = "br")

The ouput of this code is awesome