an old post but this is easy to do in Blender
a normal everyday CSV file nasa/jpl uses these a LOT
take for example Jupiters moon Amalthea (j5amalthea.tab)
from :
EAR_A_5_DDR_STOOKE_SHAPE_MODELS_V1_0
h t t p : / / sbn.psi.edu/pds/asteroid/EAR_A_5_DDR_STOOKE_SHAPE_MODELS_V1_0/data

j5amalthea.tab
has 2700 lines in this format -- first 10 lines
Code:
    0  -90     53.000000
    0  -85     56.033870
    0  -80     60.277550
    0  -75     63.620630
    0  -70     67.513030
    0  -65     71.267010
    0  -60     74.758350
    0  -55     76.839240
    0  -50     81.041340
    0  -45     83.871950
Longitude , latitude , and Radii in Kilometers
now you can just convert this to a flat plain very easy
it is a 3 band CSV ascii raw file 72 x 37 pixels ( 37 for the odd single pix at the north and south pols )
i use ISIS3 but any program that handles csv files will do
-- Even EXCEL or OO's Calc or lotus 123
a screenshot in Nip2

there is a blender plugin for importing the nasa /jpl PDS dem's
-- see the blenderartists forum and the blended plugin pages
Extensions:2.6/Py/Scripts/Import-Export/NASA IMG Importer - BlenderWiki
it opens like this in Blender