In order to generate credible 0.1 - 2 \mu m SEDs , the GAMA project requires many Gigabytes of imaging data from a number of instruments to be re-processed into a standard format .
In this paper we discuss the software infrastructure we use , and create self-consistent ugrizYJHK photometry for all sources within the GAMA sample .
Using UKIDSS and SDSS archive data , we outline the pre-processing necessary to standardise all images to a common zeropoint , the steps taken to correct for seeing bias across the dataset , and the creation of Gigapixel-scale mosaics of the three 4x12 deg GAMA regions in each filter .
From these mosaics , we extract source catalogues for the GAMA regions using elliptical Kron and Petrosian matched apertures .
We also calculate Sérsic magnitudes for all galaxies within the GAMA sample using SIGMA , a galaxy component modelling wrapper for GALFIT 3 .
We compare the resultant photometry directly , and also calculate the r band galaxy LF for all photometric datasets to highlight the uncertainty introduced by the photometric method .
We find that ( 1 ) Changing the object detection threshold has a minor effect on the best-fitting Schechter parameters of the overall population ( M ^ { * } \pm 0.055 mag , \alpha \pm 0.014 , \phi ^ { * } \pm 0.0005 h ^ { 3 } \text { } Mpc ^ { -3 } ) .
( 2 ) An offset between datasets that use Kron or Petrosian photometry regardless of the filter .
( 3 ) The decision to use circular or elliptical apertures causes an offset in M ^ { * } of 0.20 mag .
( 4 ) The best-fitting Schechter parameters from total-magnitude photometric systems ( such as SDSS modelmag or Sérsic magnitudes ) have a steeper faint-end slope than photometry dependent on Kron or Petrosian magnitudes .
( 5 ) Our Universe ’ s total luminosity density , when calculated using Kron or Petrosian r -band photometry , is underestimated by at least 15 % .