scholarly journals Assessing the hydrological suitability of floodplains for species-rich meadow restoration: a case study of the Thames floodplain, UK

2007 ◽  
Vol 11 (1) ◽  
pp. 170-179 ◽  
Author(s):  
A. J. Duranel ◽  
M. C. Acreman ◽  
C. J. Stratford ◽  
J. R. Thompson ◽  
D. J. Mould
Keyword(s):  
Agricultural Land ◽  
Hydrological Regime ◽  
Grassland Restoration ◽  
Rating Curve ◽  
Groundwater Levels ◽  
Digital Elevation ◽  
Elevation Model ◽  
Autumn And Winter ◽  
Physical And Chemical

Abstract. The physical and chemical environment of a floodplain needs to be assessed to define conservation targets for restoring it to species-rich meadows from agricultural land. A straightforward technique, widely applicable by site managers for assessing the suitability of the hydrological and hydro-chemical regime of a floodplain for wet grassland restoration, has been tested by examining the feasibility of restoring plants characteristic of NVC MG4 and MG8 communities to the Castle Meadows, Wallingford (Oxfordshire, UK). Hydro-chemical suitability has been assessed by comparing phosphorus concentrations with species-rich meadows nearby. The flooding regime was estimated based on a rating curve and a digital elevation model and groundwater levels were measured monthly in dipwells and piezometers. The hydrological regime was then compared with published reference guidelines for communities of conservation interest. For the Castle Meadows, the maximum duration of flood events in autumn and winter exceeded MG4 and MG8 species requirements across half of the site, while the depth of the groundwater table in summer exceeded species requirements in the other half. It was shown that, depending on topography, MG5 or MG13 may be more realistic vegetation targets.

scholarly journals Scale-Optimized Surface Roughness for Topographic Analysis

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 322 ◽  
Author(s):  
John B. Lindsay ◽  
Daniel R. Newman ◽  
Anthony Francioni
Keyword(s):  
Surface Roughness ◽  
Forest Cover ◽  
Agricultural Land ◽  
Spatial Scales ◽  
Grid Cell ◽  
Topographic Analysis ◽  
Digital Elevation ◽  
Locally Adaptive ◽  
Elevation Model

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 surface roughness based on the standard deviation of surface normals. This method utilizes scale partitioning and integral image processing to isolate scales of surface complexity. The computational efficiency of the method enables high scale sampling density and identification of maximum roughness for each grid cell in a digital elevation model (DEM). The approach was applied to a 0.5 m resolution LiDAR DEM of a 210 km2 area near Brantford, Canada. The case study demonstrated substantial heterogeneity in roughness properties. At shorter scales, tillage patterns and other micro-topography associated with ground beneath forest cover dominated roughness scale signatures. Extensive agricultural land-use resulted in 35.6% of the site exhibiting maximum roughness at micro-topographic scales. At larger spatial scales, rolling morainal topography and fluvial landforms, including incised channels and meander cut banks, were associated with maximum surface roughness. This method allowed for roughness mapping at spatial scales that are locally adapted to the topographic context of each individual grid cell within a DEM. Furthermore, the analysis revealed significant differences in roughness characteristics among soil texture categories, demonstrating the practical utility of locally adaptive, scale-optimized roughness.

scholarly journals EXPLORATION OF LAND RESOURCES FOR ANALYSING THE SUITABILITY OF SELECTED CROPS IN AN ADMINISTRATIVE UNIT OF THRISSUR DISTRICT, KERALA

2019 ◽  
Vol XLII-3/W6 ◽  
pp. 435-437
Author(s):  
K. Shyju ◽  
K. Kumaraswamy
Keyword(s):  
Agricultural Land ◽  
Land Suitability ◽  
Model Soil ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Digital Elevation ◽  
Administrative Unit ◽  
Elevation Model ◽  
United Nations Food ◽  
Physical And Chemical

<p><strong>Abstract.</strong> The fitness of land for a defined use is termed as land suitability. The aim of the study is to find the land suitability of for selected crops examining the indicators of land suitability. The study focuses on analysing suitability of agricultural crops in Pazhayannur Block of Thrissur District. Pazhayannur is the administrative unit (block) in the east of the Talapilli Taluk of Thrissur District in Kerala. The physical and chemical characteristics of the soils of Pazhayannur block like texture, depth, slope, erosion, pH, salinity and soil available primary nutrients (NPK), secondary nutrients and micronutrients are identified. The slope of the terrain using Cartosat-Digital Elevation Model, soil erosion, rainfall and land capability is analysed for suitability classification. Land suitability is studied for the selected crops like paddy, banana, coconut, and rubber. The weighted overlay analysis in GIS is adopted for the analysis. The parameters are weighted based on its class and its influence in suitability of specific crops. The results on agricultural land suitability for individual crops were divided into 5 categories according to the land suitability classification of the United Nations Food and Agriculture Organization (FAO). It is identified that Pazhayannur has potential for the cultivation of the selected crops. The crops show high suitability (S1) in minor proportion and moderate suitability (S2) is found in 30 percent and above and marginal suitability (S3) is noticed in lesser areas. There is few portion of land which is currently not suitable for cultivation (N1) because of its topographic limitations. The restricted areas of forest are permanently not suited for agriculture (N2).</p>

scholarly journals Conformity of the NASADEM_HGT and ALOS AW3D30 DEM with the Altitude from the Brazilian Geodetic Reference Stations: A Case Study from Brazilian Cerrado

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2935
Author(s):  
Giovana Maranhão Bettiol ◽  
Manuel Eduardo Ferreira ◽  
Luiz Pacheco Motta ◽  
Édipo Henrique Cremon ◽  
Edson Eyji Sano
Keyword(s):  
Decision Makers ◽  
Surface Model ◽  
Brazilian Cerrado ◽  
Digital Elevation ◽  
Class B ◽  
Crucial Information ◽  
Error Standard Deviation ◽  
Elevation Model ◽  
Main Region

The Brazilian Cerrado (tropical savanna) is the second largest biome in South America and the main region in the country for agricultural production. Altitude is crucial information for decision-makers and planners since it is directly related to temperature that conditions, for example, the climatic risk of rainfed crop plantations. This study analyzes the conformity of two freely available digital elevation models (DEMs), the NASADEM Merged Digital Elevation Model Global 1 arc second (NASADEM_HGT) version 1 and the Advanced Land Observing Satellite Global Digital Surface Model (ALOS AW3D30), version 3.1, with the altitudes provided by 1695 reference stations of the Brazilian Geodetic System. Both models were evaluated based on the parameters recommended in the Brazilian Cartographic Accuracy Standard for Digital Cartographic Products (PEC-PCD), which defines error tolerances according to eight different scales (from 1:1000 to 1:250,000) and classes A (most strict tolerance, for example, 0.17 m for 1:1000 scale), B, C, and D (least strict tolerance, for example, 50 m for 1:250,000 scale). Considering the class A, the NASADEM_HGT meets 1:250,000 and lower scales, while AW3D30 meets 1:100,000 and lower scales; for class B, NASADEM_HGT meets 1:100,000 scale and AW3D30 meets 1:50,000. AW3D30 presented lower values of root mean square error, standard deviation, and bias, indicating that it presents higher accuracy in relation to the NASADEM_HGT. Within eight of Cerrado’s municipalities with the highest grain production, the differences between average altitudes, measured by the Cohen’s effect size, were statistically insignificant. The results obtained by the PEC-PCD for the Cerrado biome indicate that both models can be employed in different DEM-dependent applications over this biome.

scholarly journals Environmental monitoring of soil pollution in urban areas (a case study from Heraklion city, Central Crete, Greece)

2017 ◽  
Vol 47 (2) ◽  
pp. 963
Author(s):  
E. Kokinou ◽  
C. Belonaki ◽  
D. Sakadakis ◽  
K. Sakadaki
Keyword(s):  
Magnetic Susceptibility ◽  
Urban Areas ◽  
Magnetic Measurements ◽  
Topographic Map ◽  
Near Surface ◽  
Thermomagnetic Analysis ◽  
Geological Features ◽  
Digital Elevation ◽  
Elevation Model

Main scope of the present study is to combine topographic and geological data, magnetic susceptibility and thermomagnetic analysis in order to investigate the magnetic properties of the near surface soils in possible polluted urban areas. For this purpose, a power plant with a dense traffic net around it, located in the NW section of Heraklion city in Crete was selected to be the study area. Surface soil samples have been collected from the area under investigation and they were analyzed in order to estimate the spatial distribution of the magnetic susceptibility. Loci of high values of the magnetic susceptibility within the study area gave rise to further proceed to thermomagnetic analysis of the selected samples. GIS techniques were used for mapping the magnetic measurements on the various topographic and geological features of the area. The digital elevation model was created by the digitization of the topographic map contours (1:5000 scale maps). The combination of the above techniques indicate high values of the magnetic susceptibility especially in the northeastern part of the investigated area, possibly related to pollution due to the presence of heavy metals.

scholarly journals Geodetic work at the archaeological site Tell el-Retaba

2018 ◽  
Vol 17 (2) ◽  
pp. 65-80
Author(s):  
Eva Stopková
Keyword(s):  
Spatial Data ◽  
Statistical Modelling ◽  
Archaeological Site ◽  
The North ◽  
Digital Elevation ◽  
North Eastern ◽  
Elevation Model ◽  
Modern Technologies

The paper summarizes the geodetic contribution for the Slovak team within the joint Polish-Slovak archaeological mission at Tell el-Retaba in Egypt. Surveying work at archaeological excavations is usually influenced by somewhat specific subject of study and extreme conditions, especially at the missions in the developing countries. The case study describes spatial data development according to the archaeological conventions in order to document spatial relationships between the objects in excavated trenches. The long-term sustainability of surveying work at the site has been ensured by detailed metadata recording. Except the trench mapping, Digital Elevation Model has been calculated for the study area and for the north-eastern part of the site, with promising preliminary results for further detection and modelling of archaeological structures. In general, topographic mapping together with modern technologies like Photogrammetry, Satellite Imagery, and Remote Sensing provide valuable data sources for spatial and statistical modelling of the sites; and the results offer a different perspective for the archaeological research.

scholarly journals Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

2008 ◽  
Vol 2 (1) ◽  
pp. 33-51 ◽  
Author(s):  
M. J. Beedle ◽  
M. Dyurgerov ◽  
W. Tangborn ◽  
S. J. S. Khalsa ◽  
C. Helm ◽  
...  
Keyword(s):  
Volume Change ◽  
Balance Model ◽  
Drainage Basins ◽  
Landsat Images ◽  
Glacier System ◽  
Digital Elevation ◽  
Bering Glacier ◽  
Elevation Model ◽  
Dependent Mass

Abstract. The Global Land Ice Measurements from Space (GLIMS) project has developed tools and methods that can be employed by analysts to create accurate glacier outlines. To illustrate the importance of accurate glacier outlines and the effectiveness of GLIMS standards we conducted a case study on Bering Glacier System (BGS), Alaska. BGS is a complex glacier system aggregated from multiple drainage basins, numerous tributaries, and many accumulation areas. Published measurements of BGS surface area vary from 1740 to 6200 km2, depending on how the boundaries of this system have been defined. Utilizing GLIMS tools and standards we have completed a new outline (3630 km2) and analysis of the area-altitude distribution (hypsometry) of BGS using Landsat images from 2000 and 2001 and a US Geological Survey 15-min digital elevation model. We compared this new hypsometry with three different hypsometries to illustrate the errors that result from the widely varying estimates of BGS extent. The use of different BGS hypsometries results in highly variable measures of volume change and net balance (bn). Applying a simple hypsometry-dependent mass-balance model to different hypsometries results in a bn rate range of −1.0 to −3.1 m a−1 water equivalent (W.E.), a volume change range of −3.8 to −6.7 km3 a−1 W.E., and a near doubling in contributions to sea level equivalent, 0.011 mm a−1 to 0.019 mm a−1. Current inaccuracies in glacier outlines hinder our ability to correctly quantify glacier change. Understanding of glacier extents can become comprehensive and accurate. Such accuracy is possible with the increasing volume of satellite imagery of glacierized regions, recent advances in tools and standards, and dedication to this important task.

Sign in / Sign up

Export Citation Format

Share Document