  We report a comprehensive x-ray scattering study of charge density wave
(stripe) ordering in $\rm La_{2-x}Ba_xCuO_4 (x \approx 1/8)$, for which the
superconducting $T_c$ is greatly suppressed. Strong superlattice reflections
corresponding to static ordering of charge stripes were observed in this
sample. The structural modulation at the lowest temperature was deduced based
on the intensity of over 70 unique superlattice positions surveyed. We found
that the charge order in this sample is described with one-dimensional charge
density waves, which have incommensurate wave-vectors (0.23, 0, 0.5) and (0,
0.23, 0.5) respectively on neighboring $\rm CuO_2$ planes. The structural
modulation due to the charge density wave order is simply sinusoidal, and no
higher harmonics were observed. Just below the structural transition
temperature, short-range charge density wave correlation appears, which
develops into a large scale charge ordering around 40 K, close to the spin
density wave ordering temperature. However, this charge ordering fails to grow
into a true long range order, and its correlation length saturates at $\sim
230\AA$, and slightly decreases below about 15 K, which may be due to the onset
of two-dimensional superconductivity.
