We use the star counts model of Ortiz & Lépine ( 1993 ) to perform an unprecedented exploration of the most important galactic parameters comparing the predicted counts with the 2MASS observed star counts in the J , H and K _ { S } bands for a grid of positions covering the whole sky . The comparison is made using a grid of lines-of-sight given by the HEALPix pixelization scheme . The resulting best fit values for the parameters are : ( 2120 \pm 200 ) pc for the radial scale length and ( 205 \pm 40 ) pc for the scale height of the thin disk , with a central hole of ( 2070 _ { -800 } ^ { +2000 } ) pc for the same disk ; ( 3050 \pm 500 ) pc for the radial scale length and ( 640 \pm 70 ) pc for the scale height of the thick disk ; ( 400 \pm 100 ) pc for the central dimension of the spheroid , ( 0.0082 \pm 0.0030 ) for the spheroid to disk density ratio , and ( 0.57 \pm 0.05 ) for the oblate spheroid parameter .