How to merge features contained in a shapefile based on a condition in R

Question

I have attached a shapefile ( sample ) with 4 features and each of them have gap , out , in in the field type (Refer to the attribute table). I would like to merge feature gap feature with the adjacent polygon which has the maximum area (In this case the gap would be merged with in ). My final shapefile would have 3 features (without gap ). How do I do this in R?

In ArcGIS, there is a direct tool to merge feature. I wanted to know how we do this in R.

Here is the link to the shapefile

I have used rgeos library to figure out the adjacent polygon with the maximum area. This is my code. I can't figure out how to merge this feature with the gap feature.

library(rgeos)
adj_mat <- gTouches(shp, byid=TRUE)
a <- adj_mat[which(shp@data$type=="gap"),]
area <- shp@data$SHAPE_Area[which(a=="TRUE")]
final_matching_id <- which(area==max(area))
f_gap <- shp@data[final_matching_id+1,]
f_gap

  OBJECTID SHAPE_Leng SHAPE_Area type
3       13   1.527046 0.09469124   in

Answer 1

gUnion and spRbind maybe solve your problem.

merged_d <- gUnion(shp[which(shp@data$type=="gap"),], shp[final_matching_id+1,])
not_related_d <- shp[c(1:4)[-c(which(shp@data$type=="gap"), final_matching_id+1)],]

shp2 <- spRbind(merged_d, not_related_d)

plot(shp2, col = 2:4)