Ultrahigh‐resolution mapping of peatland microform using ground‐based structure from motion with multiview stereo

Abstract

Microform is important in understanding wetland functions and processes. But collecting imagery of and mapping the physical structure of peatlands is often expensive and requires specialized equipment. We assessed the utility of coupling computer vision‐based structure from motion with multiview stereo photogrammetry (SfM‐MVS) and ground‐based photos to map peatland topography. The SfM‐MVS technique was tested on an alpine peatland in Banff National Park, Canada, and guidance was provided on minimizing errors. We found that coupling SfM‐MVS with ground‐based photos taken with a point and shoot camera is a viable and competitive technique for generating ultrahigh‐resolution elevations (i.e., <0.01 m, mean absolute error of 0.083 m). In evaluating 100+ viable SfM‐MVS data collection and processing scenarios, vegetation was found to considerably influence accuracy. Vegetation class, when accounted for, reduced absolute error by as much as 50%. The logistic flexibility of ground‐based SfM‐MVS paired with its high resolution, low error, and low cost makes it a research area worth developing as well as a useful addition to the wetland scientists' toolkit.

Assessing the peatland hummock–hollow classification framework using high-resolution elevation models: implications for appropriate complexity ecosystem modeling

“…Moreover, the surface area, spatial distribution, and relative proportion of hummock and hollow microforms present within a peatland also vary between sites (e.g. Moore et al, 2015), which may introduce bias into sampling design. For example, researchers may oversample the visually obvious extremes of the hummock-hollow continuum.…”

Assessing the Value of UAV Photogrammetry for Characterizing Terrain in Complex Peatlands

“…Following the example of previous studies [15,24,31,32], we measured the accuracy and precision of each dataset with root mean squares error (RMSE), average absolute error, mean error, median error, and median offset (the difference between dataset medians).…”

Microtopography of bare peat: a conceptual model and objective classification from high‐resolution topographic survey data

“…(1) A 5 mm resolution DEM was generated using the mean point elevation in each cell (following Mercer and Westbrook, 2016).…”

“…Recent work has identified the potential of terrestrial laser scanning (TLS) to represent fine-scale topographic variability of peatlands (Anderson et al, 2010;Luscombe et al, 2015) and to quantify erosion and deposition in peatlands (Grayson et al, 2012) through the construction of morphometric sediment budgets. In addition, Structure-from-Motion (SfM) has emerged as a potential alternative (Mercer and Westbrook, 2016) and has been used extensively to quantify the microtopography and erosion of soil surfaces (Castillo et al, 2012;Ouédraogo et al, 2014;Nouwakpo et al, 2014;Bauer et al, 2015;Kaiser et al, 2015). SfM, typically coupled with Multi-View Stereo (MVS) algorithms, generates point clouds from aerial or oblique imagery using consumer-grade digital cameras, without the need for expensive hardware (James and Robson, 2012;Westoby et al, 2012;Fonstad et al, 2013;Carrivick et al, 2016).…”