What percentage of aerial drone videos are top-down nadir videos? Most drone experts would hesitate to give that answer but when pressed they would lean towards a 40-60 split between nadir and oblique/FPV videos. In this article, we explore how accurate that might be. First, there are two di¯erent drone worlds: 1. Photogrammetry/mapping drones 2. Inspection/media/consumer drones The first of these two, benefits from a near-nadir perspective over other angles because it is helpful to create orthomosaics, surface models and measurements. Oblique coverage is helpful to façade or height estimation but not ground/roof coverage. Most commercial shot planning uses a mix, but the percentage varies on a case-by-case basis. Historically photogrammetry and mapping datasets such as OpenDroneMap/ESRI accrued nadir datasets with a dominance of top-down collections but the situation reverses with the ubiquity of hobbyist/consumer drones that generate YouTube drone footage, real-estate marketing, inspections, construction progress, emergency or rescue response, racing and cinematic content. Computer Vision has also switched to the study of these videos as evident from VisDrone/UAV tracking datasets that are forward looking. So, the market determines the ration of these videos. Photogrammetry and Mapping also benefit from still photographs rather than videos. Mapping is easier with one acquisition setup whereas oblique imagery requires using five cameras. Datasets for mapping often have varying ratios depending on use cases but they all benefit from derived orthomosaics and related products. Geospatial analytics and mapping ecosystem among these use cases, have the most skewed ratio and in favor of nadir perspective. Even when the perspectives mix in the same video between takeo¯ and landing, a credible estimate based on duration alone is elusive because of revisits. A single nadir tour of a survey area has high overlaps with those from extended rounds and revisits that usually build up a drone tour flight path. However, nadir videos help with a survey map more than any oblique videos. Any study of such a ratio amongst existing datasets is also subject to the same limitations as with analytics over a single drone video. It is inherently multimodal in nature and the search terms and retrieval frameworks no matter whether hierarchical navigable small world, exhaustive KNN, agentic or tool-based su¯er from significant variations in precision and recall with none coming close to being true to actual. The most credible reply therefore is that the answer might be unknown, but the market determines the choice.
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