Preprints
Filtering by Subject: Remote Sensing
High resolution, annual maps of field boundaries for smallholder-dominated croplands at national scales
Published: 2021-03-13
Subjects: Agriculture, Environmental Monitoring, Environmental Sciences, Geographic Information Sciences, Geography, Life Sciences, Natural Resources and Conservation, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Spatial Science, Sustainability
Mapping the characteristics of Africa's smallholder-dominated croplands, including the sizes and numbers of fields, can provide critical insights into food security and a range of other socioeconomic and environmental concerns. However, accurately mapping these systems is difficult because there is 1) a spatial and temporal mismatch between satellite sensors and smallholder fields, and 2) a lack [...]
Linkage between the Forest Fires and the Meteorological Parameters during the current climatic regime using Spatial Clustering, Regression, and Combination Matrix Analysis
Published: 2021-02-26
Subjects: Geographic Information Sciences, Geography, Physical and Environmental Geography, Remote Sensing, Spatial Science
The present study has been carried out to assess the spatial behaviour of forest fire count (FFC) data and Climate Forecast System Reanalysis (CFSR) derived meteorological parameters in Uttar Pradesh to explore the linkages amongst them. Ten years (2005 to 2014) of forest fire event data and of meteorological data have been analysed using GIS overlay, ordinary least square (OLS) regression, [...]
Plastic plants: Water hyacinths as driver of plastic transport in tropical rivers
Published: 2021-01-15
Subjects: Environmental Monitoring, Fresh Water Studies, Hydrology, Remote Sensing, Spatial Science
Recent studies suggest that water hyacinths play an important role in the transport of macroplastics in freshwater ecosystems. Forming large patches of several meters at the water surface, water hyacinths tend to entrain and aggregate large amounts of floating debris, including plastic items. Research on this topic is still novel and few studies have quantified the role of the water hyacinths in [...]
Optimizing Crop Cut Collection for Determining Field-Scale Yields in an Insurance Context
Published: 2020-11-11
Subjects: Geographic Information Sciences, Geography, Other Engineering, Remote Sensing, Spatial Science
Accurately determining crop yields at field-scale can help farmers estimate their net profit, enable insurance companies to ascertain payouts, and when aggregated at regional and national scales, crop yield estimates are critical in ensuring food security. Over the last few decades, crop cuts have been widely used to estimate field-scale crop yields. Crop cuts, while cost prohibitive, are the [...]
Using Machine-Learning Models for Field-Scale Crop Yield and Condition Modeling in Argentina
Published: 2020-11-10
Subjects: Environmental Studies, Geographic Information Sciences, Remote Sensing, Spatial Science
Accurately determining crop growth progress and crop yields at field-scale can help farmers estimate their net profit, enable insurance compa-nies to ascertain payouts, and help in ensuring food security. At field scales, the troika of management, soil and weather combine to impact crop growth pro-gress, and this progress can be monitored in-season using satellite data. Here, we use satellite [...]
A comprehensive study to understand the relationship of urbanization and population density with GRACE ΔTWS for selected study regions in India during 2003-2017
Published: 2020-10-25
Subjects: Environmental Indicators and Impact Assessment, Hydrology, Natural Resources and Conservation, Natural Resources Management and Policy, Planetary Hydrology, Remote Sensing, Sustainability, Water Resource Management
This work investigates the relationship between urbanization, population density and meteorological variables (temperature & precipitation) on groundwater storage in India during the period January'2003 to January'2017. Variations in groundwater storage have been analysed using Gravity Recovery and Climate Experiment (GRACE) derived variations of Terrestrial Water Storage (TWS). In the first part [...]
Structure-from-Motion on shallow reefs and beaches: potential and limitations of consumer-grade drones to reconstruct topography and bathymetry
Published: 2020-10-22
Subjects: Civil Engineering, Engineering, Environmental Engineering, Environmental Monitoring, Environmental Studies, Fluid Dynamics, Fresh Water Studies, Geographic Information Sciences, Hydraulic Engineering, Other Civil and Environmental Engineering, Other Environmental Sciences, Remote Sensing
Reconstructing the topography of shallow underwater environments using Structure-from-Motion – Multi View Stereo (SfM-MVS) techniques applied to aerial imagery from Unmanned Aerial Vehicles (UAVs) is a challenging problem, as it involves non-linear distortions caused by water refraction. This study presents an experiment with aerial photographs collected with a consumer-grade UAV on the [...]
Climate has contrasting direct and indirect effects on armed conflicts
Published: 2020-07-08
Subjects: Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Geography, Human Geography, International and Area Studies, Library and Information Science, Life Sciences, Nature and Society Relations, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences, Statistics and Probability
There is an active debate regarding the influence that climate has on the risk of armed conflict, which stems from challenges in assembling unbiased datasets, competing hypotheses on the mechanisms of climate influence, and the difficulty of disentangling direct and indirect climate effects. We use gridded historical non-state conflict records, satellite data, and land surface models in a [...]
Two Pixel Reference Algorithm
Published: 2020-06-18
Subjects: Engineering, Geography, Remote Sensing, Social and Behavioral Sciences
Object based image analysis (OBIA) has a unique process requirement: relate all the pixels in the segmented images to the vectorized polygons (pixel in polygon). The existing solutions are very slow in finding the pixels in a polygon. This paper proposes a novel algorithm called Two-Pixel-Reference to speed up the process. The algorithm is initially designed for segmented remote sensing images. [...]
A framework to quantify the human footprint in Africa using supply and demand of net primary production
Published: 2020-05-29
Subjects: Environmental Indicators and Impact Assessment, Environmental Sciences, Geography, Nature and Society Relations, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences, Spatial Science, Sustainability
The human-environment connection in the mostly rural drylands of Africa forms a complex, interlinked system that provides ecosystem services. This system is susceptible to climatic variability that impacts the supply of its products, and high population growth, which impacts the demand for these products. When plants remove carbon dioxide from the atmosphere through the process of photosynthesis, [...]
Machine Learning on Greenest Pixels for Crop Mapping
Published: 2020-04-14
Subjects: Geography, Remote Sensing, Social and Behavioral Sciences
Remotely sensed signals from crop fields are full of variabilities due to the complex interactions among the environment, seeds, climate, market, and farmers. It is a common phenomenon that the crops in neighbouring fields are in different growing stages, e.g., the corns are in the V5 leaf stage in one field and V10 stage in another neighbouring field. The phenomenon results in remote sensing [...]
Individual tree detection and characterization using 3D remote sensing
Published: 2020-04-12
Subjects: Forest Sciences, Geographic Information Sciences, Geography, Life Sciences, Remote Sensing, Social and Behavioral Sciences
Here, we will cover individual tree detection and characterization using 3D remote sensing. Simply, it means that point clouds are collected over a forested area using airborne laser scanning (ALS) or created using photogrammetric image interpretation and further used to detect individual trees using different algorithms. After the tree detection, the attributes of interest are predicted for each [...]
POSSIBILITIES OF CHANGE DETECTION OF TREE AND FOREST ATTRIBUTES BY COMBINING TERRESTRIAL LASER SCANNING BASED 3D POINT CLOUDS WITH UAV DATA
Published: 2020-04-02
Subjects: Forest Management, Forest Sciences, Geography, Life Sciences, Remote Sensing, Social and Behavioral Sciences
Exact and up-to-date information about forest resources is needed for decision makers when planning the use of forests. Knowledge about changes in forest environment and tree growth is a key factor for example when predicting the effects of climate change and estimating the amount of biomass and sequestered carbon in forests. New technologies, such as unmanned aerial vehicles (UAVs), allow one to [...]
Integrating UAV photogrammetry with terrestrial laser scanning to characterize managed forest stands
Published: 2020-03-04
Subjects: Forest Sciences, Geography, Life Sciences, Remote Sensing, Social and Behavioral Sciences
Terrestrial laser scanning (TLS) provides detailed three-dimensional representation of the surrounding forest structure. However, due to close-range hemispherical scanning geometry the ability of TLS technique to comprehensively characterize the upper parts of forest canopy is often limited. To overcome challenges in upper canopy characterization, TLS point cloud were complemented with a point [...]
Decadal land-use/land-cover and land surface temperature change in Dubai and implications on the urban heat island effect: A preliminary assessment
Published: 2019-06-06
Subjects: Environmental Sciences, Environmental Studies, Geographic Information Sciences, Geography, International and Area Studies, Near and Middle Eastern Studies, Other Environmental Sciences, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences
The emirate of Dubai is the most populous and most developed of the seven emirates that comprise the United Arab Emirates. By the end of the 20th century, the emirate had shifted its economy from being primarily petroleum-based to a focus on tourism and financial services. The emirate’s capital, also named Dubai, has been growing at a rapid pace; the population in 1999 was 862,000 inhabitants, [...]