John B Lindsay

University of Guelph | UOGuelph · Department of Geography

Surface roughness plays an important role in microwave remote sensing. In the agricultural domain, surface roughness is crucial for soil moisture retrieval methods that use electromagnetic surface scattering or microwave radiative transfer models. Therefore, improved characterization of Soil Surface Roughness (SSR) is of considerable importance. In...

Purpose: People with disabilities experience a disproportionate impact of extreme weather events and there is a critical need to better understand the impact that climate change has for them. Most previous reviews focus on the risk of acquiring a new disability or injury after a climate-related event and not the impact on people with pre-existing d...

It is long recognized that the processes that define the shape of the landscape operate at specific scales, and that mismatch between the scale of analysis and the scale of the process leads to erroneous results. A priori knowledge is often used in specific applications when appropriate scales are known; otherwise selecting an optimal scale of anal...

In recent decades, parallel computing has been increasingly applied to address the computational challenges of calibrating watershed hydrologic models. The purpose of this paper is to review these parallelization studies to summarize their contributions, identify knowledge gaps, and propose future research directions. These studies parallelized mod...

Multiscale methods have become progressively valuable in geomorphometric analysis as data have become increasingly detailed. This paper evaluates the theoretical and empirical properties of several common scaling approaches in geomorphometry. Direct interpolation (DI), cubic convolution resampling (RES), mean aggregation (MA), local quadratic regre...

Accurate yield estimation and optimized agricultural management is a key goal in precision agriculture, while depending on many different production attributes, such as soil properties, fertilizer and irrigation management, the weather, and topography.The need for timely and accurate sensing of these inputs at the within field-scale has led to incr...

DEM smoothing is a common pre-processing technique used to remove undesirable roughness from a DEM. However, it is hypothesized that smoothing straightens and reduces the length of overland flow paths, which is an important factor controlling modelled time-to-peak flow. Currently, there is a lack of research comparing how different smoothing techni...

Surface roughness is an important factor in many soil moisture retrieval models. Therefore, any mischaracterization of surface roughness parameters (root mean square height, RMSH, and correlation length, ʅ) may result in unreliable predictions and soil moisture estimations. In many environments, but particularly in agricultural settings, surface ro...

Fine-resolution LiDAR DEMs can represent surface features such as road and railway embankments with high fidelity. However, transportation embankments are problematic for several environmental modelling applications, and particularly hydrological modelling. Currently, there are no automated techniques for the identification and removal of embankmen...

Topographic depressions are problematic for digital elevation model (DEM) based flow-path modelling applications. Two new depression removal methods are presented in this paper, including a depression filling and a depression breaching algorithm. These new methods adopt an approach to depression removal that is in contrast to the simulated landscap...

Fine-resolution digital elevation models (DEMs), particularly those derived from airborne laser scanners (LiDAR), offer many advantages for spatial hydrological modelling applications. These detailed terrain models may be used to accurately represent topographically controlled flow-paths, even under thick forest canopy where other mapping technolog...

Digital elevation models (DEMs) reflect the morphology of landscape surfaces and attributes derived from these models, including slope, aspect, relief and topographic wetness index. DEMs have broad application in geomorphology, geology, hydrology, ecology and climatology. Here, we consider two important terrain attributes: topographic position inde...

Drainage network analysis includes several operations that quantify the topological organization of stream networks. Network analysis operations are frequently performed on streams that are derived from digital elevation models (DEMs). While these methods are suited to application with fine-resolution DEM data, this is not the case for coarse DEMs...

Fine-resolution Light Detection and Ranging (LiDAR) data often exhibit excessive surface roughness that can hinder the characterization of topographic shape and the modeling of near-surface flow processes. Digital elevation model (DEM) smoothing methods, commonly low-pass filters, are sometimes applied to LiDAR data to subdue the roughness. These t...

Previous literature has compared the performance of existing ground point classification (GPC) techniques on airborne LiDAR (ALS) data (LiDAR-light detection and ranging); however, their performance when applied to terrestrial LiDAR (TLS) data has not yet been addressed. This research tested the classification accuracy of five openly-available GPC...

Surface roughness is a terrain parameter that has been widely applied to the study of geomorphological processes. One of the main challenges in studying roughness is its highly scale-dependent nature. Determining appropriate mapping scales in topographically heterogenous landscapes can be difficult. A method is presented for estimating multiscale s...

Surface roughness is frequently measured using DEMs to characterize the ruggedness and topographic complexity of landscapes. Roughness maps have been applied in geological mapping, ecological modeling, and other environmental applications. These maps are typically derived using a roving-window approach, where kernel size dictates the scale at which...

Several landforms are known to exhibit topographic anisotropy, defined as a directional inequality in elevation. The quantitative analysis of topographic anisotropy has largely focused on measurements taken from specific landforms, ignoring the surrounding landscape. Recent research has made progress in measuring topographic anisotropy as a distrib...

A GIS-based fully-distributed model, IMWEBs-Wetland (Integrated Modelling for Watershed Evaluation of BMPs—Wetland), is developed to simulate hydrologic processes of site-specific wetlands in an agricultural watershed. This model, powered by the open-source GIS Whitebox Geospatial Analysis Tools (GAT) and advanced database technologies, allows user...

Adequate descriptions of soil surface roughness are vital for the accurate retrieval of soil moisture maps from remote sensing products. Terrestrial laser scanners (TLSs) have the potential to offer a more comprehensive method of measuring surface roughness than traditional techniques, but are underused in this application. This research examines t...

Updated online version available at: https://jblindsay.github.io/wbt_book/preface.html WhiteboxTools is an advanced geospatial data analysis engine developed by Prof. John Lindsay at the University of Guelph’s Geomorphometry and Hydrogeomatics Research Group (GHRG). The project began in January 2017 and quickly evolved in terms of its analytical c...

A new algorithm, named ROTO, is presented for creating bare-earth digital elevation models (DEMs) from input raster digital surface models (DSMs). The algorithm can remove off-terrain objects (OTOs) from DSMs derived from light-detection and ranging (LiDAR) and other fine-resolution topographic data sources. The accuracy of the method was tested us...

Economic costs, water quantity/quality benefits, and cost effectiveness of agricultural best management practices (BMPs) at a watershed scale are increasingly examined using integrated economic-hydrologic models. However, these models are typically complex and not user-friendly for examining the effects of various BMP scenarios. In this study, an o...

Digital elevation models (DEMs) are a necessary dataset for modelling the Earth’s surface; however, all DEMs contain error. Researchers can reduce this error using DEM fusion techniques since numerous DEMs can be available for a region. However, the use of a clustering algorithm in DEM fusion has not been previously reported. In this study a new DE...

This paper describes an open-source geographical information system (GIS) called Whitebox Geospatial Analysis Tools (Whitebox GAT). Whitebox GAT was designed to provide a platform for the rapid development and testing of experimental geospatial analysis methods, supported by its extensible design, integrated facilities for custom plug-in tool autho...

An informal introduction to the academic writing style intended for incoming graduate students.

Stream burning is a common flow enforcement technique used to correct surface drainage patterns derived from digital elevation models (DEM). The technique involves adjusting the elevations of grid cells that are coincident with the features of a vector hydrography layer. This paper focuses on the problematic issues with common stream burning practi...

This paper introduces a paired-sensor approach to monitoring ephemeral streamflow. Part of this approach includes the design of a new flow detec- tion sensor. This flow detection sensor addresses the limitation of previous electronic resistance (ER) sensors that use water presence as a proxy for flow for assessing hydrological connectivity, by expl...

Digital elevation models (DEMs) that are used in hydrological applications must be processed to remove sinks, mainly topographic depressions. Flow enforcement techniques include filling methods, which raise elevations within depressions, breaching, which carves channels through blockages, and hybrid methods. Despite previous research demonstrating...

Digital elevation model (DEM) derived measures of terrain ruggedness and relative topographic position are useful parameters for automated landform classification and are widely applied in soils, vegetation, and habitat mapping. These elevation residual attributes are inherently scale dependent because they are defined in the context of a local nei...

Digital elevation model (DEM) derived measures of terrain ruggedness and relative topographic position are useful parameters for automated landform classification and are widely applied in soils, vegetation, and habitat mapping. These topographic attributes are inherently scale dependent because they are defined in the context of a local neighborho...

http://www.tandfonline.com/eprint/UKz477RX4n46sY5GEej3/full#.VPdSQ1PF8mc The detailed topographic information contained in light detection and ranging (LiDAR) digital elevation models (DEMs) can present significant challenges for modelling surface drainage patterns. These data frequently represent anthropogenic infrastructure, such as road embankm...

Ephemeral streams are small headwater streams that only experience streamflow in response to a precipitation event. Due to their highly complex and dynamic spatial and temporal nature, ephemeral streams have been difficult to monitor and are in general poorly understood. This research implemented an extensive network of electrical resistance sensor...

In peatlands, poorly maintained baseflows mean that network expansion during storm events can be rapid and pronounced, resulting in large changes in catchment connectivity. This has implications for the timing and magnitude of material fluxes from these environments, understanding of which is becoming increasingly important due to peatlands' signif...

This article presents a framework for estimating a new topographic attribute derived from digital elevation models (DEMs) called maximum branch length (B max). Branch length is defined as the distance travelled along a flow path initiated at one grid cell to the confluence with the flow path passing through a second cell. B max is the longest branc...

Closed depressions, low elevation features in a landscape with no outlet point, play an important role in both surface and subsurface hydrology. These depressions, which are common in hummocky morainal landscapes, pool incoming surface flow, promoting infiltration and facilitating leaching of surface pollutants into vital groundwater resources. Due...

Ephemeral streamflow events have the potential to transport sediment and pollutants downstream, which, in predominently agricultural basins, is especially problematic. Despite the importance of ephemeral streamflow, the duration and timing of the events are characteristics that are rarely measured. Ephemeral streamflow sensors have been created in...

Over 50% of UK soil carbon is stored in peatland systems and 75% of these peatlands are upland blanket bog. The upland blanket bogs of the UK have suffered severe erosion over the last millennium so that they are widely dissected by gully systems. Gully erosion entails primary removal of particulate carbon from the peatland system but also has seco...

The episodic expansion of stream networks into their headwater ephemeral channels during storm events can result in transport of sediment and pollutants downstream, particularly in agricultural basins. Unfortunately, the duration and timing of these events are rarely measured. Ephemeral streamflow monitoring has been undertaken in the past using di...

Ephemeral streamflow events have the potential to transport sediment and pollutants downstream, which, in predominently agricultural basins, is especially problematic. Despite the importance of ephemeral streamflow, the duration and timing of the events are characteristics that are rarely measured. Ephemeral streamflow sensors have been created in...

The upland peatlands of the UK are severely eroded, with large areas affected by gully erosion. The peatlands are important areas of carbon storage and provide a range of other ecosystem services including water supply and biodiversity all of which are negatively impacted by erosion of the upland surface. The magnitude of the gully erosion, and con...

Upland peat soils in close proximity to urban and industrial areas can be contaminated with high concentrations of atmospherically deposited lead. The peat soils of the Peak District (UK) are characterised by extensive eroding gullies. Fine-resolution digital topographic data were used to map the extent and depth of these gullies. Peat samples from...

Blanket peats represent a dominant landscape type in the uplands of Britain. The hydrological status of blanket peat influences a wide range of peatland functions, with peatland water tables controlling factors such as runoff generation, water quality, vegetation distribution and rates of carbon sequestration. Water table status is therefore a cruc...

Water tables are an important control on carbon cycling and rates of carbon sequestration in peatland systems, and water table depth is therefore a key parameter in carbon models for blanket peat systems. Although there is a wide literature on blanket peat hydrology, including studies which specifically evaluate water table conditions, detailed dat...

Ephemeral streamflow events in headwater catchments are significant in terms of the flux of sediments, solutes, and discharge out of a catchment. Existing attempts to monitor these events, however, have traditionally been restricted to a limited series of manual observations or the use of temperature sensors which demand a great deal of data interp...

TAS is freely available geographic information system (GIS) for Windows® operating systems that have been developed to analyze digital elevation data. The software is predominantly used for academic research and education in universities worldwide. Interest in TAS as a research tool reflects its substantial capabilities for modeling catchment proce...

Outlet point positions taken from hydrometric stations commonly do not coincide with stream locations extracted from digital elevation models (DEMs). This is a serious problem for accurate watershed delineation of data sets containing numerous outlets, which is critical in regional-scale studies that relate catchment characteristics to basin respon...

Stream network morphometrics have been used frequently in environmental applications and are embedded in several hydrological models. This is because channel network geometry partly controls the runoff response of a basin. Network indices are often measured from channels that are mapped from digital elevation models (DEMs) using automated procedure...

Topographic indices have been used extensively in the past to model wind-related phenomena such as soil erosion, snow redistribution, and atmospheric deposition of contaminants. A new index of exposure/sheltering to wind, the channelling/deflection index (CDI), is presented and evaluated in this chapter. Unlike existing windiness indices, most of w...

Small-scale spatial variability in the concentration of magnetic minerals in peat soils has been explained by differences in the deposition and interception of magnetic minerals at the soil surface and the retention of magnetic minerals within the soil. Each of these processes is controlled by topographic conditions. Recent advances in the field of...

Increasingly, within-site and regional comparisons of peatland lead pollution have been undertaken using the inventory approach. The peatlands of the Peak District, southern Pennines, UK, have received significant atmospheric inputs of lead over the last few hundred years. A multi-core study at three peatland sites in the Peak District demonstrates...

Topographic depressions in digital elevation models (DEMs) are frequently a combination of artefacts and actual features. It is common practice to remove all digital depressions, from DEMs that are used in hydrogeomorphic applications. This practice is inappropriate because actual depressions affect many of the environmental phenomena at study. Non...

Digital elevation data are now commonly used to map channel networks automatically. This paper evaluates the sensitivity of six methods of extracting channel networks from digital elevation models (DEMs) to elevation error. As such, the robustness of channel mapping techniques against noisy data was evaluated and not the accuracy of DEM extracted c...

Artifact depressions in digital elevation models (DEMs) interrupt flow paths and alter drainage directions. Techniques for removing depressions should enforce continuous flow paths in a way that requires the least modification of the DEM. Impacts on the spatial and statistical distributions of elevation and its derivatives were assessed for four me...

Depressions are often removed from digital elevation models (DEMs) used in hydro-geomorphic applications. Light detection and ranging (lidar) and interferometric synthetic aperture radar (INSAR) DEMs of flat to mountainous landscapes were used to evaluate the occurrence of artifact depressions caused by the representation of surfaces using grids an...

Much progress has been made in extending the hydro-geomorphic modelling toolbox as a result of developments in the field of digital terrain analysis, also known as geomorphometry (Wilson and Gallant, 2000; Pike, 2002). The enhancement of computer technologies and the widespread availability of digital elevation models (DEMs) since the early 1990s h...

Measures of the size, position, and connectivity of depressional wetlands are related to runoff variations among 12 forested catchments on the Canadian Shield under varying moisture conditions. A fine-resolution digital elevation model was used to delineate wetlands within the catchments. Analyses showed that wetland metrics as predictors of runoff...

Most existing methods of calculating contributing area are unable to accurately model the pattern of contributing area on hillslopes and along valley bottoms. This paper describes a new flow algorithm, the adjustable dispersion routing algorithm (ADRA). Rather than calculating contributing area using predetermined flow characteristics that are inse...

Definition of hydrologic response units using digital elevation models (DEMs) is sensitive to the occurrence of topographic depressions. Real depressions can be important to the hydrology and biogeochemistry a catchment, often coinciding with areas of surface saturation. Artifact depressions, in contrast, result in digital ”black holes”, artificial...

The use of the measured complex permittivity of electrolyte solutions for predicting ionic species and concentration is investigated. Four artificial neural networks 􏰆ANNs􏰀 are created using a database containing permittivities 􏰆at 1.0, 1.5, and 2.0 GHz􏰀 and loss factors 􏰆at 0.3, 1.5, and 3.0 GHz􏰀 of 12 aqueous salts at various concentrations. The...

An erratum has been published for this article in Earth Surface Processes and Landforms 27(7) 2002, 795. Estimates of scour and fill in rivers that are derived by differencing topographic surfaces are known to be negatively biased by local compensation of scour and fill between surveys but the magnitude of bias is not well known. This study examine...