func filterRows(
rows []string,
timeOrigin int64, timeDistance int,
geoOrigin util.GeoPoint, geoDistance int,
) []string {
withinTimeRange := func(time int64) bool {
if time < timeOrigin-int64(timeDistance) {
return false
}
if time > timeOrigin+int64(timeDistance) {
return false
}
return true
}
pointOrigin := geoOrigin.Point()
withinGeoRange := func(geo util.GeoPoint) bool {
distance := pointOrigin.GreatCircleDistance(geo.Point())
return distance <= float64(geoDistance)/1000
}
filterRow := func(s string) (string, bool) {
row := &util.LogRow{}
util.StructFromString(s, &row)
return s, withinTimeRange(row.Timestamp) && withinGeoRange(row.Geo)
}
return map_reduce.DoMap(rows, filterRow)
}
// Note: This test involves random logic and therefore may be inconsistent. Reference the seed for repeatability.
func TestRandomGeo(t *testing.T) {
seed := time.Now().Unix()
rand.Seed(seed)
origin := util.GeoPoint{
Latitude: TEST_LATITUDE,
Longitude: TEST_LONGITUDE,
}
for i := 0; i < TEST_RANDOM_GEO_RUNS; i++ {
randGeoPoint := randomGeoPoint(origin, TEST_DISTANCE_M)
distance := origin.Point().GreatCircleDistance(randGeoPoint.Point())
if !assert.True(
t,
distance <= TEST_DISTNACE_KM,
fmt.Sprintf(
"The random point %v is %f kms away from the test origin. Seed: %d.",
randGeoPoint,
distance,
seed,
),
) {
t.FailNow()
}
}
assert.NotEqual(
t,
randomGeoPoint(origin, TEST_DISTANCE_M),
randomGeoPoint(origin, TEST_DISTANCE_M),
fmt.Sprintf("Two random points should not be the same. Seed: %d.", seed),
)
}
func randomGeoPoint(origin util.GeoPoint, distance int) util.GeoPoint {
randDistance := rand.Float64() * float64(distance) / 1000
randBearing := rand.Float64()*360 - 180
point := origin.Point()
newPoint := point.PointAtDistanceAndBearing(randDistance, randBearing)
return util.NewGeoPoint(newPoint)
}