code: public static int getFlowDirection( int i, int j ) {
          int flow = -1;
          for( int k = 1; k < 9; k++ ) {
              if (ModelsSupporter.DIR[k][0] == i && ModelsSupporter.DIR[k][1] == j) {
                  flow = k;
              }
          }
          return flow;
      }
docs: Returns the flow direction value for a given point as indexes (i, j) of the dir matrix.
  
  @param i
  @param j
  @return