Quality of terrestrial data derived from UAV photogrammetry: a case study of Hetao irrigation district in northern China

Hongming Zhang,Violette Geissen,Shuqin Li,Jiangtao Yang,Coen J Ritsema,Wenting Han,Xiaomei Yang,Jantiene E.M Baartman,Lingtong Gai,Bei Jin

doi:10.25165/j.ijabe.20181103.3012

Hongming Zhang, Violette Geissen + Show 8 more

Open Access

https://doi.org/10.25165/j.ijabe.20181103.3012

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Abstract

Most crops in northern China are irrigated, but the topography affects the water use, soil erosion, runoff and yields. Technologies for collecting high-resolution topographic data are essential for adequately assessing these effects. Ground surveys and techniques of light detection and ranging have good accuracy, but data acquisition can be time-consuming and expensive for large catchments. Recent rapid technological development has provided new, flexible, high-resolution methods for collecting topographic data, such as photogrammetry using unmanned aerial vehicles (UAVs). The accuracy of UAV photogrammetry for generating high-resolution Digital Elevation Model (DEM) and for determining the width of irrigation channels, however, has not been assessed. A fixed-wing UAV was used for collecting high-resolution (0.15 m) topographic data for the Hetao irrigation district, the third largest irrigation district in China. 112 ground checkpoints (GCPs) were surveyed by using a real-time kinematic global positioning system to evaluate the accuracy of the DEMs and channel widths. A comparison of manually measured channel widths with the widths derived from the DEMs indicated that the DEM-derived widths had vertical and horizontal root mean square errors of 13.0 and 7.9 cm, respectively. UAV photogrammetric data can thus be used for land surveying, digital mapping, calculating channel capacity, monitoring crops, and predicting yields, with the advantages of economy, speed and ease. Keywords: UAVs, GIS, DEM, irrigation area, photogrammetry, accuracy evaluation DOI: 10.25165/j.ijabe.20181103.3012 Citation: Zhang H M, Yang J T, Baartman J E M, Li S Q, Jin B, Han W T. Quality of terrestrial data derived from UAV photogrammetry: A case study of Hetao irrigation district in northern China. Int J Agric & Biol Eng, 2018; 11(3): 171–177.

Highlights

Raster digital elevation models (DEMs) can represent continuous topographic elevations above a common base level in two ways, as digital surface models (DSMs) and digital terrain models (DTMs)
The difference between the measured elevations and the 0.15 m DEM elevations ranged from 9.87 cm to 29.1 cm (Figure 6), where negative and positive values imply that the DEM elevations were over- and underestimated, respectively
unmanned aerial vehicles (UAVs) photogrammetry has been widely used in recent years

Summary

Introduction

Raster digital elevation models (DEMs) can represent continuous topographic elevations above a common base level in two ways, as digital surface models (DSMs) and digital terrain models (DTMs). A DSM is a model in which each pixel has the value of the highest feature at the pixel location, and vegetation, structures, and water are filtered out of DTMs. DEMs are widely used in automated hydrological analyses and for the extraction of watershed characteristics, including slope steepness[1], slope length[2], direction of water flow[3,4], drainage networks[5,6], surface roughness of agricultural soils[7], and flood simulation[8]. Recent developments in remote sensing with unmanned aerial vehicles (UAVs), known as drones, have emerged from new, flexible, high-resolution technologies for the collection of topographic data.

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