# The relation between the scale of captured aerial photos and scale of the extracted features,

Discussion created by Jamal432@gmail.com on Feb 3, 2015
Latest reply on Mar 14, 2017 by kevcri

The relation between the scale of captured aerial photos and scale of the extracted features,

The overlaps (60% front and 20% side) between the captured aerial photos ensures having 3D model and thus orthophoto can be built and features and contours can be extracted.

The issue here is that if the aerial photos are captured with a scale of 1/9,000 then which mapping scale and contour intervals can be derived from this scale (1/9,000)?

The scale of aerial photos can be easily calculated if the focal length (f) of the camera and flight height (h) above the ground are provided from the formula below:

Scale = f/h

For example, if the focal length is 305mm and the flight height is 2700 m, then the scale=(305/1000)/2700 = 1/9,000

1. Then which mapping scale can be set for the extracted features from the aerial photos of 1/9,000 scale?
2. Which contour interval can be extracted from this scale?

Is there mathematical equations that support such calculations?

Best

Jamal