ABSTRACT:Unmanned aerial vehicles (UAV) have gained tremendous interest as a platform for surveying and mapping over the last few years, and have opened up a new realm of opportunities for surveying, orthophoto production, 3D modelling and feature extraction. UAVs provide a viable and affordable alternative for the airborne and space borne sensors for the medium/large scale mapping. This paper argues that universities should expand their education and training programs to include UAV-based geomatics operations and application development. Based on the author's own experience as well other cases, details are developed and presented in this paper with respect to the likely syllabi and practical assignments. Alternatives for hardware and software support will be briefly discussed.
Reliable building delineation in very high resolution (VHR) satellite imagery can be achieved by precise disparity information extracted from stereo pairs. However, off-nadir VHR images over urban areas contain many occlusions due to building leaning that creates gaps in the extracted
disparity maps. The typical approach to fill these gaps is by interpolation. However, it inevitably degrades the quality of the disparity map and reduces the accuracy of building detection. Thus, this research proposes a registration-based technique for mapping the disparity of off-terrain
objects to avoid the need for disparity interpolation and normalization. The generated disparity by the proposed technique is then used to support building detection in off-nadir VHR satellite images. Experiments in a high-rise building area confirmed that 75 percent of the detected building
roofs overlap precisely the reference data, with almost 100 percent correct detection. These accuracies are substantially higher than those achieved by other published research.
The recent evolution of Unmanned Aerial Vehicles (UAVs) as measuring instruments has become attractive for many surveying applications in civil engineering including the volumetric computations of earthworks in the construction of a highway. The application of softcopy photogrammetry to UAV acquired imagery has the potential to reduce data acquisition costs, time and with suitable accuracy for earthworks mapping and volumetrics. Their performance, however, is not well understood for these applications. This investigation tests the ability of the UAVs and photogrammetric software to generate volumes for the layers of material used in road construction, as well as to analyse their accuracies and limitations. Specifically, this study assesses the feasibility of UAV-based surveying in generating volumes for general earthworks in highway/road construction. Additionally, the study compares the performance of UAV-based surveying to that of Total Station surveying. Performance is evaluated along the required time for image acquisition and generating the final products, the required personnel and overall cost of survey. A segment of the Churchill Roosevelt Extension to Manzanilla was used in the assessment.
Interest in the civilian applications of Unmanned Aerial Systems (UAS) has been growing worldwide, especially in government and commercial tasks such as surveillance, search and rescue, inspection of infrastructure, agriculture, mining, and mapping. Likewise, Trinidad and Tobago (T&T) has been witnessing a growing interest and application of commercial and non-commercial UAS operations. However, there is little assessment for the growth of the UAS market nor is there characterisation of UAS-based activities since the pertinent regulations established in 2016. This study seeks to formally identify the emerging UAS landscape in T&T during the period 2015 to 2019. As such, this study maps and characterises the spatial and temporal patterns of UAS distribution, then appraises the various categories for the existing operations. To achieve these goals, this study utilised qualitative and quantitative techniques of Geoinformatics. The intent for this study is to provide a perspective on the growth and the implications of the UAS industry in T&T, and to guide strategic planning among organisations with a stake in the emergence of UAS into civil airspace.
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