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MAP_ROBUST Real
Robust weighting factor. A number between 0 and +infty.
Robust weighting gives the natural weight to UV cells whose natural weight is lower than a given threshold. In contrast, if the natural weight of the UV cell is larger than this threshold, the weight is set to this (uniform) threshold. The UV cell size is defined by MAP_UVCELL and the threshold value is in MAP_ROBUST.
0 means natural weighting, which is optimal for point sources. The Robust weighting factor controls the resolution: better resolution is obtained for small values (at the expense of noise), resolution approaching the natural weighting scheme for large values. Larger UV cell size give higher angular resolution (but again more noise).
MAP_ROBUST around .5 to 1 is a good compromise between noise increase and angular resolution.