# Graphic Applications of Unmanned Aerial Vehicles (UAVs) in the Study of Industrial Heritage Assets
## 2 SWOT Analysis Applied to UAV
### Strengths  
S1. Different UAVs typologies: Different UAVs typologies are available in the market. One classification considers the wing arrangement: rotatory or fixed. Rotatory wing models are widely employed for economic reasons and because they allow the UAVs to remain hover immobile in the air. This fact makes it possible to obtain higher accuracy images. On the other hand, fixed wing UAVs are employed to analyse higher land extensions requiring less capture image time and less battery autonomy. Hence, fixed or rotatory wing UAVs can be selected based on the research needs of each case study.  
S2. Low equipment cost: The stability of the aircraft and the possibility of incorporating different devices are the main characteristics that affect the UAV price. For professional uses, the cheapest models (rotatory wings) are around \(\epsilon\)1000 (i.e., Mavic and Phantom series). A high-quality visual camera (S3) is integrated and good flight stability can be assumed in these models. Fixed wing models are more expensive that rotatory wing ones. In spite of this, a professional fixed wing UAV with an integrated high-quality visual camera can be acquired for \(\epsilon\)2000. Notwithstanding, the price of UAVs that incorporate different devices increases to approximately \(\epsilon\)5000, and, depending on the characteristics of the device, can reach \(\epsilon\)10,000. In spite of the fact UAV prices are higher than those of a conventional photographic camera, the opportunities offered by UAV technology in heritage asset research are higher (O1, O3, O4 and O5).  
S3. High image and video quality: A common professional UAV incorporates a visual camera that can capture high resolution images and film high definition (HD) videos. This fact allows obtaining images with the aircraft at a sufficient distance to reduce the accident risks that could affect the aircraft performance and cause material or personal damages.  
S4. Low human risks: Heritage assets are usually in a dilapidated state or are situated in difficult to access areas. Heritage building structures are often unstable, so access poses a high risk to persons. Furthermore, other heritage assets have very reduced access zones that persons cannot physically access or present a risky environment for people. The remote-control system allows the UAV to access these hard-to-reach places, eliminating any risk to persons during the experimental research process.  
S5. Low contamination technology: UAV flights do not generate polluting emissions to the environment due to their use of rechargeable batteries. Besides, it is important to highlight that this technology allows the replacement of elements (i.e., wings, cover structure, external battery, devices) without the need to replace the aircraft completely, reducing the waste generation.  
S6. High dimensional accuracy: Professional UAVs incorporate Global Positioning System (GPS) (0) technology. This technology allows generating georeferenced orthophotographs that, using photogrammetry techniques, can create three-dimensional models related to Geographical Information Systems (GIS) with errors of less than centimetre magnitude. This strength provides an opportunity to digitalize heritage assets with high dimensional accuracy (O5).