American Institute of Certified Planners (AICP) Practice Exam

What is the primary characteristic that differentiates an aerial photograph from an orthophoto?

1. An orthophoto has a uniform scale

2. An aerial photograph is rectified

3. An aerial photograph is a photographic map

4. An orthophoto is not based on aerial imaging

The correct answer is: An orthophoto has a uniform scale

The option indicating that an orthophoto has a uniform scale is the primary characteristic that differentiates it from a conventional aerial photograph. An aerial photograph captures images from above the Earth's surface, but it may have varying scales due to factors like tilt, elevation changes, and distortion caused by the camera lens and atmospheric conditions. These variations can affect measurements and interpretations made from the photograph. In contrast, an orthophoto is produced by correcting these distortions through a process known as orthorectification. This process ensures that the orthophoto maintains a uniform scale across the entire image, allowing for accurate measurements and a reliable representation of the Earth's features, akin to a map. The uniformity in scale is crucial for applications in planning, surveying, and analysis, where precision is essential. The other options do not accurately reflect the key distinguishing feature. For example, aerial photographs are generally not rectified, making them vary in scale and thus less suitable for precise applications. The idea that an aerial photograph is a photographic map is misleading, as it emphasizes a characteristic that is not inherently true without rectification. Lastly, stating that orthophotos are not based on aerial imaging is incorrect, as they are indeed derived from aerial photographs, just processed to eliminate distortions