View source: R/RHG_graph_coefficients.R

RHG_graph_coefficients | R Documentation |

Computes the regional curve power function coefficients from a table of regional hydraulic curve coordinates contained in a built-in table.

```
RHG_graph_coefficients(region, drainageArea, dimensionType)
```

`region` |
character; The region that a dimension will be calculated for. See the regional_curves$region field for a complete list. |

`drainageArea` |
numeric; The upstream drainage area of the location of the dimension (in square miles). |

`dimensionType` |
character; The dimension type: "area", "depth", "width" |

Regional curves are typically displayed on log-log plots. This
method is required to extract the formula for calculating the y-axis
value on these graphs (i.e., cross-sectional area, width, mean depth)
from the x-axis value (i.e., drainage area). Monomial relationships of
the form `y=ax^m`

, known as power functions, appear as straight
lines in a logâ€“log graph, with the exponent (`m`

) and constant
(`a`

) term corresponding to slope and intercept of the line
(`y = mx + b`

).

Used internally to convert historic studies that do not report regional relationships using the "power function" convention.

A data frame containing the value of slope (`m`

) and intercept
(`a`

) for the requested region and hydraulic dimension.

Other data:
`RHG_graph()`

,
`region_min_max()`

,
`regional_curves()`

,
`regional_curve`

```
# Calculate the slope and intercept for a watershed with drainage area = 1
# square mile in the Eastern United States region.
RHG_graph_coefficients(region = "Eastern United States",
drainageArea = 1,
dimensionType = "area")
```

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