Setting geofence boundaries in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of geofence boundary check

What is the output of this code that checks if a drone is inside a rectangular geofence boundary?

Drone Programming

geofence = {'min_lat': 10.0, 'max_lat': 20.0, 'min_lon': 30.0, 'max_lon': 40.0}
drone_position = {'lat': 15.0, 'lon': 35.0}
inside = (geofence['min_lat'] <= drone_position['lat'] <= geofence['max_lat']) and (geofence['min_lon'] <= drone_position['lon'] <= geofence['max_lon'])
print('Inside geofence' if inside else 'Outside geofence')

A SyntaxError

B Outside geofence

C Inside geofence

D KeyError

💡 Hint

Check if the drone's latitude and longitude are within the min and max values of the geofence.

The drone's latitude 15.0 is between 10.0 and 20.0, and longitude 35.0 is between 30.0 and 40.0, so it is inside the geofence.

🧠 Conceptual

intermediate

Understanding geofence polygon boundaries

Which data structure is best to represent a polygon geofence boundary for a drone?

A A string describing the area name

B A single latitude and longitude point representing the center

C A dictionary with min and max latitude only

D A list of latitude and longitude coordinate pairs defining the polygon vertices

💡 Hint

A polygon needs multiple points to define its shape.

A polygon geofence is defined by multiple vertices, so a list of coordinate pairs is the best representation.

🔧 Debug

advanced

Fix the geofence boundary check error

This code is supposed to check if a drone is inside a geofence but raises an error. What is the error?

Drone Programming

geofence = {'min_lat': 10.0, 'max_lat': 20.0, 'min_lon': 30.0, 'max_lon': 40.0}
drone_position = {'lat': 25.0, 'lon': 35.0}
inside = (geofence['min_lat'] <= drone_position['lat'] <= geofence['max_lat']) and (geofence['min_lon'] <= drone_position['lon'] <= geofence['max_lon'])
print('Inside geofence' if inside else 'Outside geofence')

A SyntaxError due to missing colon

B No error; output is 'Outside geofence'

C TypeError due to comparing string with float

D KeyError because 'lat' key is missing

💡 Hint

Check the drone's latitude value and the geofence limits.

The drone's latitude 25.0 is outside the max_lat 20.0, so inside is false and output is 'Outside geofence'. No error occurs.

📝 Syntax

advanced

Identify the syntax error in geofence code

Which option contains a syntax error in defining a geofence dictionary?

A geofence = {'min_lat': 10.0, 'max_lat': 20.0, 'min_lon': 30.0, 'max_lon' 40.0}

B geofence = {'min_lat': 10.0, 'max_lat': 20.0, 'min_lon': 30.0, 'max_lon': 40.0}

C geofence = dict(min_lat=10.0, max_lat=20.0, min_lon=30.0, max_lon=40.0)

D }0.04 :'nol_xam' ,0.03 :'nol_nim' ,0.02 :'tal_xam' ,0.01 :'tal_nim'{ = ecnefoeg

💡 Hint

Look for missing punctuation in dictionary syntax.

Option A is missing a colon between 'max_lon' and 40.0, causing a syntax error.

🚀 Application

expert

Calculate if drone is inside a polygon geofence

Given a polygon geofence defined by vertices and a drone position, which option correctly determines if the drone is inside the polygon using the ray casting algorithm?

Drone Programming

def is_inside_polygon(point, polygon):
    x, y = point
    inside = False
    n = len(polygon)
    p1x, p1y = polygon[0]
    for i in range(n + 1):
        p2x, p2y = polygon[i % n]
        if y > min(p1y, p2y):
            if y <= max(p1y, p2y):
                if x <= max(p1x, p2x):
                    if p1y != p2y:
                        xinters = (y - p1y) * (p2x - p1x) / (p2y - p1y) + p1x
                    if p1x == p2x or x <= xinters:
                        inside = not inside
        p1x, p1y = p2x, p2y
    return inside

polygon = [(0,0), (0,10), (10,10), (10,0)]
drone = (5,5)
print(is_inside_polygon(drone, polygon))

A True

B False

C SyntaxError

D IndexError

💡 Hint

The drone is inside the square polygon defined by the vertices.

The drone point (5,5) lies inside the square polygon, so the function returns True.