infraFDTD.assist (version 0.6)

PrepFiles: Generate Input Files for infraFDTD

Description

infraFDTD requires text files defining the topography, atmospheric sound speed structure, atmospheric density structure, and station locations. PrepFiles generates these files from variables in R.

Usage

PrepFiles(X, sta, dh, fn_topo, fn_c, fn_rho, fn_sta, c = 335, rho = 1.2,
xlim = range(X$x), ylim = range(X$y), c_function = NA, rho_function =
NA, z_extent = NaN)

Arguments

X

DEM. Must include elements x (vector), y (vector), z (matrix: nrow = length(x), ncol = length(y))

sta

Station info. Must include elements x, y (vectors in meters, in same coordinate system as X). Station names are optionally stored in element sta. z is optional and should only be included if you want microphones in the air. If z is missing, all stations are located on surface. Otherwise, NaN elevations are located on the surface, and non-NaN elevations are preserved.

dh

Grid Spacing (m).

fn_topo

Output file name for DEM.

fn_c

Output file name for sound speed.

fn_rho

Output file name for density.

fn_sta

Output file name for stations.

c

Sound speed (m/s). If a scalar, sound speed is homogeneous in the model. If a vector with length equal to the number of vertical nodes in the model, sound speed varies vertically according to the vector (this is inconvenient; it's normally better to use c_function for a variable atmosphere). This input is ignored if c_function is provided.

rho

Density (kg/m^3). If a scalar, density is homogeneous in the model. If a vector with length equal to the number of vertical nodes in the model, density varies vertically according to the vector (this is inconvenient; it's normally better to use rho_function for a variable atmosphere). This input is ignored if rho_function is provided.

xlim

X limits of output DEM--must be contained within the boundaries of DEM.

ylim

Y limits of output DEM--must be contained within the boundaries of DEM.

c_function

Function giving sound speed as a function of height. Consider using approxfun() to generate this from an atmospheric profile.

rho_function

Function giving density as a function of height. Consider using approxfun() to generate this from an atmospheric profile.

z_extent

Vertical thickness of model (m); must be greater than total relief in model.

Value

None; print and file output only.

Details

This function does not generate a param.h file; however, it does print values that can be copied to param.h by the user.

Consider using package rNOMADS to find the atmospheric profile.

Examples

# NOT RUN {
## generate the DEM
data(volcano) # Maunga Whau (NZ) from built-in package "datasets"
DEM = list(x = 10 * 1:87, y = 10 * 1:61, z = volcano)

## choose the station locations
sta = list(x = c(100, 500), y = c(100, 500))

## show the topo map with stations
image(DEM, col = terrain.colors(20))
contour(DEM, add = TRUE)
points(sta, pch = 25, bg = 1)

## make the input files for infraFDTD, using the default homogeneous
## sound speed and density
PrepFiles(X = DEM, sta = sta, dh = 10, fn_topo = 'topo.txt', fn_c =
'c.txt', fn_rho = 'rho.txt', fn_sta = 'sta.txt')
# }