;---Data are from some gridded source

  dirtxt = "./"
  filtxt = "var.txt"
  pthtxt = dirtxt+filtxt

  ncols = 8
  nrows = numAsciiRow(pthtxt)
  values = asciiread(pthtxt,(/nrows,ncols/),"float")
  printVarSummary(values)
  print("=====")

;---After looking at the text file:
;---It is clear the data are on a rectilinear grid. 
;---Extract pertient information.

  LAT  = values(:,0)    
  dLAT = 0.20
  nlat = toint((max(LAT)-min(LAT))/dLAT)+1

  LON  = values(:,1)    
  dLON = 0.20
  mlon = toint((max(LON)-min(LON))/dLON)+1

  print("GRID SIZE: ("+nlat+","+mlon+")")
  print("=====")

;---Create latitude and longitude coordinates

  lat  = values(0::nlat,0)       ; 1st column
  lat!0     = "lat"
  lat@units = "degrees_north"
  print(lat)

  lon  = values(0:mlon-1,1)       ; 2nd column
  lon!0     = "lon"
  lon@units = "degrees_east"
  print(lon)

;---Read variables; reshape onto grid

  srad = onedtond(values(:,2),(/nlat,mlon/)) 
  tmax = onedtond(values(:,3),(/nlat,mlon/))

; points for which interpolation required t

  lat_pts = (/10.38, 10.40/)
  lon_pts = (/79.85, 79.49/)

  ntmax = linint2_points_Wrap(lat,lon,tmax,False,lat_pts,lon_pts,0)
  print(ntmax)