nearest bus - direction / heading

[Elixeus]

when querying for nearest bus - we want to return the direction of the bus as well as buses that are coming to this stop and not output buses that have already passed this stop

[vr00n]

Options:
make sure you return buses that have not already crossed this position.

So select st_near(my_location) from device table where device's previous "n" locations were > (distance from this and next bus stop)

or compute a heading from the device table
https://stackoverflow.com/questions/3932502/calculate-angle-between-two-latitude-longitude-points

[vr00n]

Option1 : Use Math

def angleFromCoordinate(lat1, long1, lat2, long2):
    dLon = (long2 - long1)

    y = math.sin(dLon) * math.cos(lat2)
    x = math.cos(lat1) * math.sin(lat2) - math.sin(lat1) * math.cos(lat2) * math.cos(dLon)

    brng = math.atan2(y, x)

    brng = math.degrees(brng)
    brng = (brng + 360) % 360
    brng = 360 - brng # count degrees clockwise - remove to make counter-clockwise

    return brng

Option 2 : Use google computeHeading (not a service though)

You just can use the google maps computeHeading:

var point1 = new google.maps.LatLng(lat1, lng1);
var point2 = new google.maps.LatLng(lat2, lng2);
var heading = google.maps.geometry.spherical.computeHeading(point1,point2);