**5. Conclusions**

This research has demonstrated the viability of a method for calculating the energy efficiency of public lighting installations. It also provides a very useful tool that can be used to show their electrical and lighting properties in geographic information systems.

The electricity consumption data were obtained from smart electric meters in the streetlight control box. These meters provide information regarding the entire installation in real time. These consumption data take into account the energy consumed by lamps, auxiliary equipment, and energy losses due to the Joule effect of the distribution lines.

The geometrical distribution of the luminaires, as well as the streetlight control box, were easily georeferenced through the aerial images provided by the camera. Finally, the luminous properties were obtained by calculating the luminance emitted by the surface of the road. For this purpose, it was necessary to calibrate the airborne camera by using the image of a light source of known luminance. The calculation of the energy efficiency is almost immediate based on the electricity consumption, luminance of the road surface, and road surface dimensions.

Another important aspect is the scalability of the method. This procedure can be easily extrapolated to entire neighborhoods or cities because the only difference is the number of images needed to cover the entire metropolitan area. However, the methodology is always the same because each image is analyzed individually.

**Author Contributions:** Conceptualization, Methodology and Writing-Original Draft Preparation, O.R.; Investigation and Resources, E.M.-M.; Validation and Formal Analysis, D.G.-L. and F.A.-D.

**Funding:** This research received no external funding.

**Acknowledgments:** We wish to thank the city council of Deifontes (Granada) and its mayor, Francisco Abril Tenorio, for facilitating the tests carried out in the municipality. We also would like to thank Norberto Laborías Olmedo for the technical support in the Electrical Engineering Laboratory of the University of Granada.

**Conflicts of Interest:** The authors declare no conflict of interest.
