RSurvey (version 0.7-4)

ProcessData: Process Data

Description

This function performs data processing on the state variables.

Usage

ProcessData(d, type = "p", coerce.rows = NULL, ply = NULL,
            grid.res = list(x = NA, y = NA),
            grid.mba = list(n = NA, m = NA, h = 11))

Arguments

d

data.frame; the data to be processed, a table with variables x, y, z, t, vx, vy, and vz.

type

character; a 1-character string giving the resulting output type. The following values are possible: "p" for points and "g" for interpolated grid.

coerce.rows

logical; a vector indicating rows in d to include in the processed data set. NA

ply

gpc.poly; if type = "p" a polygon that defines either the data limits, else if type = "g" a crop region for gridded data.

grid.res

list; numeric components giving the grid spacing along the x- and y-axis for interpolated values, see SetPreferences.

grid.mba

list; integer components giving the input parameters for the multilevel B-splines algorithm, see SetPreferences.

Value

• If type = "p" returns a data frame with variables:
• x, y
  numeric; a vector of x and y coordinates.
• z
  numeric; a vector of state variable values (optional).
• t
  POSIXct; a vector of time stamps (optional).
• vx, vy, vz
  numeric; a vector of velocity components in the x, y and z directions, respectively (optional).
• If type = "g" returns a list with components:
• x, y
  numeric; a vector of grid line locations at which the values in z are measured.
• z
  matrix; interpolated surface of state variable with rows and columns corresponding to grid lines in the x and y directions, respectively.
• vx, vy, vz
  matrix; interpolated surface of velocity components with rows and columns corresponding to grid lines in the x and y directions (optional).
• vf
  numeric; volumetric flux (optional).

Details

Any row in the d data table with NA values for either x or y is removed. Rows are also removed where coerce.rows is FALSE. The spatial domain may be limited using a polygon defined in the xy-plane. Interpolated grid values corresponding to grid nodes located outside the polygon boundary are set to NA.

See Also

point.in.polygon, CutoutPolygon, mba.points

Examples

x <- c(7.8, 5, 2.2, 3.7, NA, -1.6, -7.5)
y <- c(-2.3, -4.7, -2.2, -2.3, -3.4, -1.6, -7.5)
z <- c(-0.9, -1.2, -2.4, -2.4, -0.4, 0.1, 2)
t <- c("4/23/2009 10:43", "4/24/2009 11:20", "4/24/2009 12:08",
       "4/24/2009 12:50", "4/24/2009 13:51", "4/24/2009 14:24",
       "4/24/2009 14:44")
t <- as.POSIXct(t, format = "%m/%d/%Y %H:%M")

data.raw <- as.data.frame(list(x = x, y = y, z = z, t = t))
data.pts <- ProcessData(data.raw, type = "p")
data.grd <- ProcessData(data.pts, type = "g")

ply <- as(cbind(c(-4, 2, -6), c(-7, -3, -3)), "gpc.poly")
grid.res <- list(x = 0.2, y = 0.5)
data.grd <- ProcessData(data.pts, type = "g", ply = ply,
                        grid.res = grid.res)