  In this paper we illustrate the technique used by the New Vacuum Solar
Telescope to increase the spatial resolution of two-dimensional (2D) solar
spectroscopy observation involving two dimensions of space and one of
wavelength. Without an image stabilizer at the NVST, a large scale wobble
motion is present during the spatial scanning, whose instantaneous amplitude
could reach up to 1.3" due to the earth's atmosphere and the precision of the
telescope guiding system, and seriously decreases the spatial resolution of 2D
spatial maps composed with the scanning spectra. We make the following effort
to resolve this problem: the imaging system (e.g., the TiO-band) is used to
record and detect the displacement vectors of solar image motion during the
raster scan, in both the slit and scanning directions. The spectral data (e.g.,
the Ha line) which are originally obtained in time sequence are corrected and
re-arranged in space according to those displacement vectors. Raster scans are
carried out in several active regions with different seeing conditions (two
rasters are illustrated in this paper). Given a certain spatial sample and
temporal resolution, the spatial resolution of the composed 2D map could be
close to that of the slit-jaw image. The resulting quality after correction is
quantitatively evaluated with two methods. Two-dimensional physical quantity,
such as the line-of-sight velocities in multi-layer of the solar atmosphere, is
also inferred demonstrating the effect of this technique.
