PRO EXAMPLE

   ; Pick a seed, so you see what I see. Create data.
   
seed = -1L
lat = RANDOMU(seed, 40) * (24./1.0) + 24
lon = RANDOMU(seed, 40) * 40.0/1.0 - 112
data = RANDOMU(seed, 40) * 1000

   ; Colors for plot.
   
TVLCT, [255, 0], [255, 255], [0,0], 1

   ; Set up the map projection of the Eastern US.
   
MAP_SET, 15, -87, 0, LIMIT=[24,-115,49,-67], $
   /CONTINENTS, /USA, /MERCATOR
   
   ; Plot the random data locations.
   
PLOTS, lon, lat, PSYM=4, COLOR=2

   ; Grid the irregularly spaced data.
   
gridData= SPH_SCAT(lon, lat, data, $
   BOUNDS=[-115., 24., -67., 49.], GS=[0.5,0.5], BOUT=bout)
   
   ; Calculate xlon and ylat vectors corresponding to gridded data.
   
s = SIZE(gridData)
xlon = FINDGEN(s(1))*((bout(2) - bout(0))/(s(1)-1)) + bout(0)
ylat = FINDGEN(s(2))*((bout(3) - bout(1))/(s(2)-1)) + bout(1)

   ; Put the contours on the map.
   
CONTOUR, gridData, xlon, ylat, /OVERPLOT, NLEVELS=10, C_COLOR=1

END