FUNCTION GRIDDATA_EXAMPLE, OLAT = olat, OLON = olon, $
  TRIMETHOD = trimethod, SPHERE = sphere, METHOD = method
  
COMPILE_OPT IDL2
On_Error, 2

if n_elements(trimethod) EQ 0 then trimethod = "qhull"
if n_elements(method) EQ 0 then method = "NaturalNeighbor"

; here follows the info for the irregular-in-latitdue grid 
nLat = 510  & latRange = [-30.023445, 30.563103]
nLon = 730  & lonRange = [ 30.375000, 121.500000]
PS = [(lonRange[1]-lonRange[0])/nLon, 0.0] ;pixel size - varies in Y
;longitude has regular spacing
lon = FINDGEN(nLon) * PS[0] + lonRange[0] 

;latitude has irregular spacing
lat = $
[  30.563103,  30.455408,  30.347595,  30.239664,  30.131615,  30.023445, $
   29.915159,  29.806755,  29.698233,  29.589594,  29.480837,  29.371964, $
   29.262974,  29.153868,  29.044645,  28.935307,  28.825853,  28.716284, $
   28.606602,  28.496803,  28.386890,  28.276863,  28.166723,  28.056469, $
   27.946102,  27.835623,  27.725029,  27.614325,  27.503508,  27.392578, $
   27.281538,  27.170387,  27.059126,  26.947754,  26.836271,  26.724678, $
   26.612976,  26.501165,  26.389246,  26.277216,  26.165079,  26.052835, $
   25.940483,  25.828022,  25.715456,  25.602783,  25.490004,  25.377117, $
   25.264128,  25.151031,  25.037828,  24.924524,  24.811113,  24.697599, $
   24.583982,  24.470263,  24.356438,  24.242512,  24.128485,  24.014355, $
   23.900124,  23.785791,  23.671358,  23.556826,  23.442192,  23.327461, $
   23.212629,  23.097698,  22.982670,  22.867542,  22.752319,  22.636997, $
   22.521578,  22.406063,  22.290451,  22.174746,  22.058943,  21.943045, $
   21.827053,  21.710968,  21.594790,  21.478516,  21.362150,  21.245691, $
   21.129141,  21.012499,  20.895765,  20.778942,  20.662027,  20.545023, $
   20.427929,  20.310745,  20.193472,  20.076111,  19.958662,  19.841127, $
   19.723503,  19.605795,  19.487997,  19.370117,  19.252150,  19.134098, $
   19.015961,  18.897741,  18.779436,  18.661049,  18.542580,  18.424028, $
   18.305393,  18.186678,  18.067883,  17.949007,  17.830050,  17.711014, $
   17.591900,  17.472706,  17.353436,  17.234085,  17.114660,  16.995157, $
   16.875578,  16.755922,  16.636192,  16.516386,  16.396507,  16.276554, $
   16.156528,  16.036428,  15.916256,  15.796012,  15.675697,  15.555311, $
   15.434855,  15.314327,  15.193731,  15.073067,  14.952333,  14.831532, $
   14.710663,  14.589726,  14.468724,  14.347655,  14.226521,  14.105323, $
   13.984059,  13.862732,  13.741342,  13.619888,  13.498372,  13.376794, $
   13.255155,  13.133454,  13.011694,  12.889874,  12.767994,  12.646055, $
   12.524059,  12.402004,  12.279893,  12.157724,  12.035501,  11.913220, $
   11.790885,  11.668495,  11.546052,  11.423554,  11.301004,  11.178402, $
   11.055747,  10.933042,  10.810286,  10.687479,  10.564622,  10.441716, $
   10.318763,  10.195760,  10.072710,   9.949614,   9.826470,   9.703281, $
    9.580048,   9.456768,   9.333445,   9.210078,   9.086668,   8.963216, $
    8.839721,   8.716186,   8.592608,   8.468991,   8.345335,   8.221639, $
    8.097904,   7.974132,   7.850322,   7.726475,   7.602592,   7.478673, $
    7.354719,   7.230730,   7.106707,   6.982651,   6.858562,   6.734440, $
    6.610287,   6.486102,   6.361887,   6.237642,   6.113367,   5.989064, $
    5.864732,   5.740373,   5.615986,   5.491573,   5.367134,   5.242669, $
    5.118179,   4.993666,   4.869129,   4.744568,   4.619986,   4.495381, $
    4.370755,   4.246108,   4.121441,   3.996755,   3.872049,   3.747326, $
    3.622584,   3.497825,   3.373050,   3.248259,   3.123452,   2.998630, $
    2.873794,   2.748945,   2.624082,   2.499207,   2.374320,   2.249422, $
    2.124513,   1.999594,   1.874665,   1.749728,   1.624782,   1.499829, $
    1.374868,   1.249901,   1.124928,   0.999949,   0.874966,   0.749979, $
    0.624988,   0.499994,   0.374997,   0.249999,   0.125000,  -0.000000, $
   -0.125000,  -0.249999,  -0.374997,  -0.499994,  -0.624988,  -0.749979, $
   -0.874966,  -0.999949,  -1.124928,  -1.249901,  -1.374868,  -1.499829, $
   -1.624782,  -1.749728,  -1.874665,  -1.999594,  -2.124513,  -2.249422, $
   -2.374320,  -2.499207,  -2.624082,  -2.748945,  -2.873794,  -2.998630, $
   -3.123452,  -3.248259,  -3.373050,  -3.497825,  -3.622584,  -3.747326, $
   -3.872049,  -3.996755,  -4.121441,  -4.246108,  -4.370755,  -4.495381, $
   -4.619986,  -4.744568,  -4.869129,  -4.993666,  -5.118179,  -5.242669, $
   -5.367134,  -5.491573,  -5.615986,  -5.740373,  -5.864732,  -5.989064, $
   -6.113367,  -6.237642,  -6.361887,  -6.486102,  -6.610287,  -6.734440, $
   -6.858562,  -6.982651,  -7.106707,  -7.230730,  -7.354719,  -7.478673, $
   -7.602592,  -7.726475,  -7.850322,  -7.974132,  -8.097904,  -8.221639, $
   -8.345335,  -8.468991,  -8.592608,  -8.716186,  -8.839721,  -8.963216, $
   -9.086668,  -9.210078,  -9.333445,  -9.456768,  -9.580048,  -9.703281, $
   -9.826470,  -9.949614, -10.072710, -10.195760, -10.318763, -10.441716, $
  -10.564622, -10.687479, -10.810286, -10.933042, -11.055747, -11.178402, $
  -11.301004, -11.423554, -11.546052, -11.668495, -11.790885, -11.913220, $
  -12.035501, -12.157724, -12.279893, -12.402004, -12.524059, -12.646055, $
  -12.767994, -12.889874, -13.011694, -13.133454, -13.255155, -13.376794, $
  -13.498372, -13.619888, -13.741342, -13.862732, -13.984059, -14.105323, $
  -14.226521, -14.347655, -14.468724, -14.589726, -14.710663, -14.831532, $
  -14.952333, -15.073067, -15.193731, -15.314327, -15.434855, -15.555311, $
  -15.675697, -15.796012, -15.916256, -16.036428, -16.156528, -16.276554, $
  -16.396507, -16.516386, -16.636192, -16.755922, -16.875578, -16.995157, $
  -17.114660, -17.234085, -17.353436, -17.472706, -17.591900, -17.711014, $
  -17.830050, -17.949007, -18.067883, -18.186678, -18.305393, -18.424028, $
  -18.542580, -18.661049, -18.779436, -18.897741, -19.015961, -19.134098, $
  -19.252150, -19.370117, -19.487997, -19.605795, -19.723503, -19.841127, $
  -19.958662, -20.076111, -20.193472, -20.310745, -20.427929, -20.545023, $
  -20.662027, -20.778942, -20.895765, -21.012499, -21.129141, -21.245691, $
  -21.362150, -21.478516, -21.594790, -21.710968, -21.827053, -21.943045, $
  -22.058943, -22.174746, -22.290451, -22.406063, -22.521578, -22.636997, $
  -22.752319, -22.867542, -22.982670, -23.097698, -23.212629, -23.327461, $
  -23.442192, -23.556826, -23.671358, -23.785791, -23.900124, -24.014355, $
  -24.128485, -24.242512, -24.356438, -24.470263, -24.583982, -24.697599, $
  -24.811113, -24.924524, -25.037828, -25.151031, -25.264128, -25.377117, $
  -25.490004, -25.602783, -25.715456, -25.828022, -25.940483, -26.052835, $
  -26.165079, -26.277216, -26.389246, -26.501165, -26.612976, -26.724678, $
  -26.836271, -26.947754, -27.059126, -27.170387, -27.281538, -27.392578, $
  -27.503508, -27.614325, -27.725029, -27.835623, -27.946102, -28.056469, $
  -28.166723, -28.276863, -28.386890, -28.496803, -28.606602, -28.716284, $
  -28.825853, -28.935307, -29.044645, -29.153868, -29.262974, -29.371964, $
  -29.480837, -29.589594, -29.698233, -29.806755, -29.915159, -30.023445]
 
;transform to 2d arrays of locations - but hold them in vectors
lon = REFORM(lon # replicate(1.0 ,nLat), nLon * nLat)
lat =  REFORM(replicate(1.0 ,nLon) # lat, nlon * nlat)

;makeup some data
zValue = REFORM(hanning(nLon, nLat), nLon * nLat)

;here follow the specs for the "output" regular grid upon which 
;I want to interpolate the above data
oPS = [0.166667, 0.166667] 
oLonRange = [30.500, 121.667]
oLatRange = [-30.1667, 30.500]
oNLon = (oLonRange[1]-oLonRange[0])/oPS[0] + 1
oNLat = (oLatRange[1]-oLatRange[0])/oPS[1] + 1
oLon =  FINDGEN(oNLon) * oPS[0] + oLonRange[0]
oLat =  FINDGEN(oNLat) * oPS[1] + oLatRange[0]

;transform output coords to 2d arrays
oLon = oLon # replicate(1.0, oNLat)
oLat = replicate(1.0, oNLon) # oLat

CASE StrLowCase(trimethod) of 
  "qhull": QHULL, lon, lat, tr, /DELAUNAY
  "triangulate": TRIANGULATE, lon, lat, tr, /DEGREES
  ELSE: Message, "Method not recognized: " + trimethod
ENDCASE


Z = GRIDDATA(lon, lat, zValue, /DEGREES, SPHERE = KEYWORD_SET(sphere), $
    METHOD = method, MISSING = 0.0, $
    XOUT = oLon, YOUT = oLat, TRIANGLES = tr ) 

  
RETURN, REFORM(Z, oNLon, oNLat)
END