expos_model {ExposR}

Modeling Functions

Description

expos_model uses a raster file of elevation values, a specified wind direction, and a specified inflection angle to create a raster file of wind exposure values (0 = missing data, 1 = protected, 2 = exposed). The user can specify if coordinates are lat/long; otherwise lat/long is assumed if X values are between -180 and 180 and Y values are between -90 and 90. If lat/long, horizontal and vertical units are assumed to be degrees and meters, respectively; otherwise horizontal and vertical units must be the same. Columns are assumed to be closely aligned with true North (0 degrees); if not, the map orientation (azimuth) must be specified in degrees. The name of the input file is assumed to be "dem.tif".

expos_damage uses output from the EXPOS and HURRECON models to create a raster of hurricane wind damage where topographic exposure at each location is determined by peak wind direction. If a location is protected, the enhanced Fujita scale rating from HURRECON is reduced by a specified amount. This function requires a hurricane file in GeoTiff format created by HURRECON, exposure files created by EXPOS for the eight cardinal wind directions (N, NE, E, etc), and a reprojection file in CSV format (reproject.csv) that contains lat/long coordinates in degrees for the lower left and upper right corners of the digital elevation model.

Usage

expos_model(
  wind_direction,
  inflection_angle,
  lat_long = NULL,
  orient = 0,
  save = TRUE,
  exp_path = NULL
)

expos_damage(
  hurricane,
  inflection_angle,
  protect,
  save = TRUE,
  exp_path = NULL
)

Arguments

wind_direction

wind direction (degrees)

inflection_angle

inflection angle (degrees)

lat_long

whether coordinate system is latitude/longitude

orient

map orientation (degrees)

save

whether to save results to file

exp_path

path for current set of model runs

hurricane

hurricane name (as it appears in tif file)

protect

how much to reduce damage in protected areas (number of Fujita scale ratings)

Value

raster of modeled exposure values

raster of modeled wind damage values

Examples

exp_path <- system.file("", package="ExposR", mustWork=TRUE)
expos_model(wind_direction=135, inflection_angle=6, save=FALSE, exp_path=exp_path)