flightconflicts

commit 779b5fda418fa4b71c19afef9f1652af6acd4d6e
parent 17a7f66bbae83ae6eff7b652d08cf267d78f8172
Author: eamoncaddigan <eamon.caddigan@gmail.com>
Date:   Mon, 12 Sep 2016 14:23:48 -0400

Pulling out flat-Earth approximation code for flexibility/modularity.

Diffstat:
M
R/calculateSLoWC.R
 | 
15
+++++++--------
A
R/trajectoryToXYZ.R
 | 
26
++++++++++++++++++++++++++
A
man/trajectoryToXYZ.Rd
 | 
21
+++++++++++++++++++++

3 files changed, 54 insertions(+), 8 deletions(-)
diff --git a/R/calculateSLoWC.R b/R/calculateSLoWC.R
@@ -22,17 +22,16 @@ calculateSLoWC <- function(trajectory1, trajectory2) {
   lon0 <- mean(c(trajectory1$longitude, trajectory2$longitude))
   lat0 <- mean(c(trajectory1$latitude, trajectory2$latitude))
   
+  t1 <- trajectoryToXYZ(trajectory1, c(lon0, lat0))
+  t2 <- trajectoryToXYZ(trajectory2, c(lon0, lat0))
+  
   # Flat Earth approximation of aircraft position and velocity
-  ac1XYZ <- cbind(lonlatToXY(trajectory1$longitude, trajectory1$latitude, 
-                             lon0, lat0),
-                  trajectory1$altitude)
-  ac2XYZ <- cbind(lonlatToXY(trajectory2$longitude, trajectory2$latitude, 
-                             lon0, lat0),
-                  trajectory2$altitude)
+  ac1XYZ <- t1$position
+  ac2XYZ <- t2$position
   
   # Convert bearing/speed to velocity vector.
-  ac1Velocity <- bearingToXY(trajectory1$bearing, trajectory1$groundspeed)
-  ac2Velocity <- bearingToXY(trajectory2$bearing, trajectory2$groundspeed)
+  ac1Velocity <- t1$velocity
+  ac2Velocity <- t2$velocity
   
   # Distance between aircraft
   dXYZ <- ac2XYZ - ac1XYZ
diff --git a/R/trajectoryToXYZ.R b/R/trajectoryToXYZ.R
@@ -0,0 +1,26 @@
+#' Convert trajectories to Easting/Northing representation.
+#' 
+#' @param trajectory A flighttrajectory object.
+#' @param origin A length 2 numeric vector giving the origin lon/lat for the
+#'   conversion.
+#' @return A flattrajectory object.
+trajectoryToXYZ <- function(trajectory, origin) {
+  if (!is.flighttrajectory(trajectory)) {
+    stop("'trajectory' must be an instance of flighttrajectory")
+  }
+  if (!is.numeric(origin) || length(origin) != 2) {
+    stop("'origin' must be a numeric vector of length 2")
+  }
+  
+  trajectoryXY <- lonlatToXY(trajectory$longitude, trajectory$latitude, 
+                             origin[1], origin[2])
+  
+  velocityXY <- bearingToXY(trajectory$bearing, trajectory$groundspeed)
+  
+  flattrajectory <- list(origin = origin,
+                         position = cbind(trajectoryXY, trajectory$altitude),
+                         velocity = velocityXY)
+  class(flattrajectory) <- "flattrajectory"
+  
+  return(flattrajectory)
+}
diff --git a/man/trajectoryToXYZ.Rd b/man/trajectoryToXYZ.Rd
@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/trajectoryToXYZ.R
+\name{trajectoryToXYZ}
+\alias{trajectoryToXYZ}
+\title{Convert trajectories to Easting/Northing representation.}
+\usage{
+trajectoryToXYZ(trajectory, origin)
+}
+\arguments{
+\item{trajectory}{A flighttrajectory object.}
+
+\item{origin}{A length 2 numeric vector giving the origin lon/lat for the
+conversion.}
+}
+\value{
+A flattrajectory object.
+}
+\description{
+Convert trajectories to Easting/Northing representation.
+}
+