  We have measured the HI power spectrum of the nearly face-on spiral galaxy
NGC 1058 from radio-interferometric observations using a visibility based
estimator. The power spectrum is well fitted by two different power laws
$P(U)=AU^{\alpha}$, one with $\alpha =- 2.5\pm 0.6$ at small length-scales
$(600 {\rm pc} {\rm to} 1.5 {\rm kpc})$ and another with $\alpha =- 1.0\pm 0.2$
at large length-scales $(1.5 {\rm kpc} {\rm to} 10.0
  {\rm kpc})$. We interpret this change in the slope of the power spectrum as a
transition from 3D turbulence at small length-scales to 2D turbulence in the
plane of the galaxy's disk at large length-scales. We use the observed break in
the power spectrum to estimate the galaxy's scale-height, which we find to be $
490 \pm 90 $ pc.
