par = list()
par$bank.min.dist = 6 # meters

for(i in c(2:length(data$x[ix]))){

      # add the actual point
      banks$x[[bank]] = c(banks$x[[bank]], data$x[ix.l][i-1])
      banks$y[[bank]] = c(banks$y[[bank]], data$y[ix.l][i-1])

      # calculate distance between consecutive bank points
      cb_dist = ( ( data$x[ix][i] - data$x[ix][i-1] )^2 + ( data$y[ix][i] - data$y[ix][i-1] )^2 ) ^(1/2)

      # if distance larger than threshold distance interpolate
      if(cb_dist > par$bank.min.dist){

        # calculate number of artificial points
        nr_of_pts = ceiling(cb_dist / par$bank.min.dist)
        ap = ap + nr_of_pts

        # add artificial points
        for(ido in c(1: (nr_of_pts-1))){

          banks$x[[bank]] = c(banks$x[[bank]], data$x[ix][i-1] + ( ( (data$x[ix][i] - data$x[ix][i-1]) / nr_of_pts ) * ido ) )
          banks$y[[bank]] = c(banks$y[[bank]], data$y[ix][i-1] + ( ( (data$y[ix][i] - data$y[ix][i-1]) / nr_of_pts ) * ido ) )

        }

      }

    }