Photometric metallicity map of the Small Magellanic Cloud
  We have created an estimated metallicity map of the Small Magellanic Cloud
(SMC) using the Magellanic Cloud Photometric Survey (MCPS) and Optical
Gravitational Lensing Experiment (OGLE III) photometric data. This is a first
of its kind map of metallicity up to a radius of $\sim$ 2.5$^{\circ}$. We
identify the RGB in the V, (V$-$I) colour magnitude diagrams of small
subregions of varying sizes in both data sets. We use the slope of the RGB as
an indicator of the average metallicity of a subregion, and calibrate the RGB
slope to metallicity using available spectroscopic data for selected
subregions. The average metallicity of the SMC is found to be [Fe/H] = $-$0.94
dex ($\sigma$[Fe/H] = 0.09) from OGLE III, and [Fe/H] = $-$0.95 dex
($\sigma$[Fe/H] = 0.08) from MCPS. We confirm a shallow but significant
metallicity gradient within the inner SMC up to a radius of 2.5$^{\circ}$
($-$0.045$\pm$0.004 dex deg$^{-1}$ to $-$0.067$\pm$0.006 dex deg$^{-1}$).
