flightconflicts

Tools to analyze conflicts between aircraft.
git clone https://git.eamoncaddigan.net/flightconflicts.git
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test_calculateTCPA.R (1415B)

      1 library(flightconflicts)
      2 context("calculateTCPA")
      3 
      4 library(geosphere)
      5 library(flightpathr)
      6 
      7 kacy <- c(-74.5771667, 39.4575833)
      8 kphl <- c(-75.2408658, 39.8722494)
      9 
     10 meterPer200Knots <- 0.009719
     11 
     12 test_that("correct tCPA for head-on collision", {
     13   trajectory1 <- createTrajectory(kacy[1], kacy[2], 
     14                                   bearing = bearingRhumb(kacy, kphl),
     15                                   groundspeed = 200)
     16   trajectory2 <- createTrajectory(kphl[1], kphl[2], 
     17                                   bearing = bearingRhumb(kphl, kacy),
     18                                   groundspeed = 200)
     19   
     20   expect_equal(calculateTCPA(trajectory1, trajectory2),
     21                distGeo(kacy, kphl)/2 * meterPer200Knots,
     22                tolerance = 1)
     23 })
     24 
     25 test_that("TCPA for actual trajectories", {
     26   numPoints <- round(distGeo(kacy, kphl) * meterPer200Knots)
     27   coords <- gcIntermediate(kacy, kphl,
     28                            n = numPoints)
     29   trajectory1 <- createTrajectory(coords[, "lon"], coords[, "lat"])
     30   trajectory2 <- createTrajectory(rev(coords[, "lon"]), rev(coords[, "lat"]))
     31   tcpaVector <- calculateTCPA(trajectory1, trajectory2)
     32   
     33   expect_equal(tcpaVector[seq(ceiling(numPoints/2)+1, numPoints)],
     34                0 * seq(ceiling(numPoints/2)+1, numPoints))
     35   
     36   expect_equal(diff(tcpaVector[seq(1, floor(numPoints/2))]), 
     37                -1*diff(seq(1, floor(numPoints/2))),
     38                tolerance = 1e-3)
     39 })