mamquam            package:HyperbolicDist            R Documentation

_S_i_z_e _o_f _g_r_a_v_e_l _f_r_o_m _M_a_m_q_u_a_m _R_i_v_e_r

_D_e_s_c_r_i_p_t_i_o_n:

     Size of gravels collected from a sandbar in the Mamquam River,
     British Columbia, Canada. Summary data, giving the frequency of
     observations in 16 different size classes.

_U_s_a_g_e:

     data(mamquam)

_F_o_r_m_a_t:

     The 'mamquam' data frame has 16 rows and 2 columns.

       [, 1]  midpoints  midpoints of intervals (psi units)
       [, 2]  counts     number of observations in interval

_D_e_t_a_i_l_s:

     Gravel sizes are determined by passing clasts through templates of
     particular sizes. This gives a range in which the size of each
     clast lies. Sizes (in mm) are then converted into psi units by
     taking the base 2 logarithm of the size. The midpoints specified
     are the midpoints of the psi unit ranges, and counts gives the
     number of observations in each size range. The classes are of
     length 0.5 psi units.  There are 3574 observations.

_S_o_u_r_c_e:

     Rice, Stephen and Church, Michael (1996) Sampling surficial
     gravels: the precision of size distribution percentile estimates.
     _J. of Sedimentary Research_, *66*, 654-665.

_E_x_a_m_p_l_e_s:

     data(mamquam)
     str(mamquam)
     attach(mamquam)
     ## construct data from frequency summary, taking all observations
     ## at midpoints of intervals
     psi <- rep(midpoints,counts) 
     summary(psi)
     ## fit the hyperbolic distribution
     fit.hyperb(psi)

     ## actually fit.hyperb can deal with frequency data
     fit.hyperb(midpoints, freq=counts)

