  The scale lengths of the old stars and ionized gas distributions are compared
for similar samples of Virgo Cluster members and field spiral galaxies via
Halpha and broad R-band surface photometry. While the R-band and Halpha scale
lengths are, on average, comparable for the combined sample, we find
significant differences between the field and cluster samples. While the Halpha
scale lengths of the field galaxies are a factor of 1.14 +- 0.07 longer on
average than their R-band scale lengths, the Halpha scale lengths of Virgo
Cluster members are on average 20% smaller than their R-band scale lengths.
Furthermore, in Virgo, the scale length ratios are correlated with the size of
the star-forming disk: galaxies with smaller overall Halpha extents also show
steeper radial falloff of star formation activity. At the same time, we find no
strong trends in scale length ratio as a function of other galaxy properties
including galaxy luminosity, inclination, morphological type, central R--band
light concentration, or bar type. Our results for Halpha emission are similar
to other results for dust emission, suggesting that Halpha and dust have
similar distributions. The environmental dependence of the Halpha scale length
places additional constraints on the evolutionary process(es) that cause gas
depletion and a suppression of the star formation rate in clusters of galaxies.
