mamquam: Size of Gravels from Mamquam River

Description Usage Format Details Source Examples

Description

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.

Usage

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Format

The mamquam data frame has 16 rows and 2 columns.

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

Details

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.

Source

Rice, Stephen and Church, Michael (1996) Sampling surficial gravels: the precision of size distribution percentile estimates. J. of Sedimentary Research, 66, 654–665.

Examples

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data(mamquam)
str(mamquam)
attach(mamquam)
### Construct data from frequency summary, taking all observations
### at midpoints of intervals
psi <- rep(midpoints, counts)
barplot(table(psi))
### Fit the hyperbolic distribution
hyperbFit(psi)

### Actually hyperbFit can deal with frequency data
hyperbFit(midpoints, freq=counts)

HyperbolicDist documentation built on May 1, 2019, 7:38 p.m.