  We present results of age and metallicity gradient analysis inferred from
both optical and near-infrared surface photometry. The analysis is based on a
sample of 36 nearby early-type galaxies, obtained from the Early Data Release
of the Sloan Digital Sky Survey and the Two Micron All Sky Survey. Surface
brightness profiles were derived in each band, and used to study the color
gradients of the galaxies. Using simple stellar population models with both
optical and near infrared colors, we may interpret the color gradients in term
of age and metallicity gradients of galaxies. Using $g_Z \equiv d \log Z_{\rm
met} / d \log R $ and $g_A = d \log {\rm Age} / d \log R $ to represent the
metallicity and age gradients, we found a median value of $g_Z=-0.25\pm 0.03$
for the metallicity gradient, with a dispersion $\sigma_{g_Z}=0.19\pm0.02$. The
corresponding values for the age gradient were $g_A=0.02\pm 0.04$ and
$\sigma_{g_A}=0.25\pm0.03$. These results are in good agreement with recent
observational results, as well as with recent simulations that suggest both
monolithic collapse and major merger have played important roles in the
formation of early-type galaxies. Our results demonstrate the potential of
using multi-waveband colors obtained from current and future optical and
infrared surveys in constraining the age and metallicity gradients of
early-type galaxies.
