Any multi criteria decision analysis process need to weigh the criteria and
to know any weighting method the best to use according the nature and degree
of complexity of the problem. There are four method for criteria weighting
Rank, Rating, Pairwise and Trade-off methods. In this study, which was done
in Najaf – Iraq used this methods to weigh the seventeen criteria used to select
landfill site within integration of (GIS -MCDA) in Najaf governorate. There is
no difference between the results within Pairwise or Ranking method only in
size of landfill in west part of study area (five sites were selected in each try).
Within trade-off and rating methods, there are more than five site were
selected.
Keys words: Rating, Ranking, Pairwise Comparison, Trade-Off Method