diff --git a/src/st_bbox.jl b/src/st_bbox.jl
index 083a3b2..ecc32b2 100644
--- a/src/st_bbox.jl
+++ b/src/st_bbox.jl
@@ -36,10 +36,9 @@ end
 
 # size: array size
 function bbox2cellsize(b::bbox, size)
-  range = bbox2range(b)
   nlon, nlat = size[1:2]
-  cellx = (range[2] - range[1]) / nlon
-  celly = (range[4] - range[3]) / nlat
+  cellx = (b.xmax - b.xmin) / nlon
+  celly = (b.ymax - b.ymin) / nlat
   cellx, celly
 end
 
@@ -50,7 +49,6 @@ bbox2vec(b::bbox) = [b.xmin, b.ymin, b.xmax, b.ymax]
 
 
 
-
 function st_bbox(lon, lat)
   cellx = abs(lon[2] - lon[1])
   celly = abs(lat[2] - lat[1])
@@ -58,13 +56,7 @@ function st_bbox(lon, lat)
     maximum(lon) + cellx / 2, maximum(lat) + celly / 2)
 end
 
-
-
-
-function st_bbox(f::String)
-  gdalinfo(f)["bbox"]
-end
-
+st_bbox(f::String) = gdalinfo(f)["bbox"]
 
 # get large bbox, also know as bbox_merge
 function st_bbox(bs::Vector{bbox})
@@ -83,8 +75,6 @@ function bbox_overlap(b::bbox, box::bbox; cellsize=1 / 240, reverse_lat=true)
   ilon = findall(b.xmin .< Lon .< b.xmax)
   ilat = findall(b.ymin .< Lat .< b.ymax)
   # 由于精度的原因，有一些会存在空值
-  # ilon = indexin(lon, Lon)
-  # ilat = indexin(lat, Lat)
   ## 必定是所有的数据都在box中，不然是程序的错误
   @assert length(lon) == length(ilon)
   @assert length(lat) == length(ilat)
@@ -92,9 +82,6 @@ function bbox_overlap(b::bbox, box::bbox; cellsize=1 / 240, reverse_lat=true)
 end
 
 
-# function st_mosaic()
-# end
-
 
 ## add support for Rasters
 using Rasters: Raster
@@ -107,10 +94,46 @@ function st_bbox(ra::Raster)
   st_bbox(lon, lat)
 end
 
+st_bbox(ras::Vector{<:Raster}) = st_bbox(st_bbox.(ras))
+
+
+function st_cellsize(r::Raster)
+  lon = r.dims[1] # X
+  lat = r.dims[2] # Y
+
+  lon[2] - lon[1], lat[2] - lat[1] # cellx, celly
+end
+
+function st_mosaic(ras::Vector{<:Raster}; missingval=NaN)
+  r = ras[1]
+  T = eltype(r)
+  missingval = T(missingval)
+
+  cellsize = st_cellsize(r)
+  
+  box = st_bbox(ras)
+  lon2, lat2 = bbox2dims(box; cellsize)
+  
+  _size = length(lon2), length(lat2)
+  nd = ndim(r)
+  jcol = repeat([:], nd - 2)
+
+  nd >= 3 && (_size=_size..., size(r)[3:end])  
+  A = fill(missingval, _size)
+  
+  for i in eachindex(ras)
+    r = ras[i]
+    b = st_bbox(r)
+    ilon, ilat = bbox_overlap(b, box; cellsize)
+    A[ilon, ilat, jcol...] = r.data
+  end
+  Raster(A, box; missingval)
+end
+
 
 export bbox,
   bbox2cellsize,
   bbox2range, bbox2vec,
   bbox2dims, bbox2ndim,
   bbox_overlap
-export st_bbox, bbox_overlap
+export st_bbox, st_mosaic