rescale_catchment_characteristics {nhdplusTools}

Rescale Catchment Characteristics

Description

Given catchment characteristics to retrieve or process will aggregate and / or split the characteristics according to a lookup table.

Usage

rescale_catchment_characteristics(
  vars,
  lookup_table,
  refactored_areas = NULL,
  catchment_characteristics = NULL,
  catchment_areas = NULL
)

Arguments

vars

data.frame containing 'characteristic_id' retrieved from get_characteristics_metadata and 'summary_statistic' indicating which summary statistic should be applied to rescale each characteristic. Accepted values are "sum," "length_weighted_mean," "area_weighted_mean," "min," and "max."

lookup_table

data.frame containing 'id' numeric vector of identifiers at the desired scale; "comid" is a numeric vector of NHDPlusV2 identifiers; "member_comid" contains formatted NHDPlusV2 COMIDs indicating that the catchments in question need to be split. If catchments have not been split, the columns "comid" and "member_comid" should be identical.

refactored_areas

data.frame containing columns "featureid" and "areasqkm." Used to retrieve adjusted catchment areas in the case of split catchments. If not provided, either no split catchments can be considered or the 'catchment_areas' parameter is required.

catchment_characteristics

data.frame containing columns "characteristic_id", "comid", "characteristic_value", and "percent_nodata". If not provided, it will be retrieved from get_catchment_characteristics using the characteristic ids from 'vars' and the comids from 'lookup_table'.

catchment_areas

data.frame containing columns "comid", "areasqkm", "split_catchment_areasqkm", and "split_area_prop". If not provided, it will be retrieved from 'refactored_areas' and/or get_vaa.

Details

NOTE: Since this algorithm works on catchment characteristics that are spatial averages, when splitting, the average condition is apportioned evenly to each split. In some cases, such as with land cover or elevation, this may not be appropriate and source data should be used to derive new characteristics. In addition, this function handles catchment areas for split catchments but makes no adjustments for the length of flowlines in those catchments. Therefore, requests for length-weighted mean values may not be appropriate when working with split catchments.

Examples

vars <- data.frame(characteristic_id = c("CAT_IMPV11","CAT_BASIN_AREA"),
                   summary_statistic = c("area_weighted_mean","sum"))
lookup_table <- data.frame(id = rep(10012268, 2),
                           comid = c(4146596, 4147382),
                           member_comid = c(4146596, 4147382))
rescale_catchment_characteristics(vars, lookup_table)

vars <- data.frame(characteristic_id = c("CAT_ELEV_MIN","CAT_ELEV_MAX"),
                   summary_statistic = c("min","max"))
lookup_table <- data.frame(id = rep(10012268, 2),
                           comid = c(4146596, 4147382),
                           member_comid = c(4146596, 4147382))
rescale_catchment_characteristics(vars, lookup_table)

vars <- data.frame(characteristic_id = c("CAT_EWT","CAT_TWI", "CAT_BASIN_AREA"),
                   summary_statistic = c("area_weighted_mean", "area_weighted_mean","sum"))
lookup_table <- data.frame(id = c(10012268, 10012268, 10024047, 10024048),
                           comid = c(4146596, 4147382, 4147396, 4147396),
                           member_comid = c("4146596", "4147382", "4147396.1", "4147396.2"))
comid_areas <- data.frame(featureid = c("4146596", "4147382", "4147396.1", "4147396.2"),
                               areasqkm = c(0.9558, 11.9790, 6.513294, 1.439999))
rescale_catchment_characteristics(vars, lookup_table, refactored_areas = comid_areas)