scholarly journals Expedited generation of terrain digital classes in flat areas from UAV images for precision agriculture purposes

2017 ◽  
Vol 8 (2) ◽  
pp. 828-832
Author(s):  
M. C. Pineda ◽  
C. Perdomo ◽  
R. Caballero ◽  
A. Valera ◽  
J. A. Martínez-Casasnovas ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Topographic Wetness Index ◽  
Site Specific ◽  
Soil Variables ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Elevation Model ◽  
Uav Images ◽  
Specific Management

Precision agriculture (PA) requires reasonably homogeneous areas for site-specific management. This work explores the applicability of digital terrain classes obtained from a digital elevation model derived from UAV-acquired images, to define management units in in a relative flat area of about 6 ha. Elevation, together with other terrain variables such as: slope degree, profile curvature, plan curvature, topographic wetness index, sediment transport index, were clustered using the Fuzzy Kohonen Clustering Network (FKCN). Four terrain classes were obtained. The result was compared with a map produced by a classification of soil properties previously interpolated by ordinary kriging. The results suggest that areas for site-specific management can be defined from terrain classes based on environmental covariates, saving time and cost in comparison with interpolation of soil variables.

scholarly journals Evaluating digital terrain indices for soil wetness mapping – a Swedish case study

2014 ◽  
Vol 18 (9) ◽  
pp. 3623-3634 ◽  
Author(s):  
A. M. Ågren ◽  
W. Lidberg ◽  
M. Strömgren ◽  
J. Ogilvie ◽  
P. A. Arp
Keyword(s):  
Surface Flow ◽  
Topographic Wetness Index ◽  
Water Index ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Soil Disturbances ◽  
Soil Wetness ◽  
Elevation Model ◽  
Terrain Indices

Abstract. Trafficking wet soils within and near stream and lake buffers can cause soil disturbances, i.e. rutting and compaction. This – in turn – can lead to increased surface flow, thereby facilitating the leaking of unwanted substances into downstream environments. Wet soils in mires, near streams and lakes have particularly low bearing capacity and are therefore more susceptible to rutting. It is therefore important to model and map the extent of these areas and associated wetness variations. This can now be done with adequate reliability using a high-resolution digital elevation model (DEM). In this article, we report on several digital terrain indices to predict soil wetness by wet-area locations. We varied the resolution of these indices to test what scale produces the best possible wet-areas mapping conformance. We found that topographic wetness index (TWI) and the newly developed cartographic depth-to-water index (DTW) were the best soil wetness predictors. While the TWI derivations were sensitive to scale, the DTW derivations were not and were therefore numerically robust. Since the DTW derivations vary by the area threshold for setting stream flow initiation, we found that the optimal threshold values for permanently wet areas varied by landform within the Krycklan watershed, e.g. 1–2 ha for till-derived landforms versus 8–16 ha for a coarse-textured alluvial floodplain.

scholarly journals PREPROCESSING OF SATELLITE DATA FOR URBAN OBJECT EXTRACTION

2015 ◽  
Vol XL-3/W2 ◽  
pp. 115-120 ◽  
Author(s):  
T. Krauß
Keyword(s):  
Digital Terrain Model ◽  
Stereo Pair ◽  
Spectral Classification ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Elevation Model ◽  
Processing Steps

Very high resolution (VHR) DSMs (digital surface models) derived from stereo- or multi-stereo images from current VHR satellites like WorldView-2 or Pléiades can be produced up to the ground sampling distance (GSD) of the sensors in the range of 50 cm to 1 m. From such DSMs the digital terrain model (DTM) representing the ground and also a so called nDEM (normalized digital elevation model) describing the height of objects above the ground can be derived. In parallel these sensors deliver multispectral imagery which can be used for a spectral classification of the imagery. Fusion of the multispectral classification and the nDEM allows a simple classification and detection of urban objects. In further processing steps these detected urban objects can be modeled and exported in a suitable description language like CityGML. In this work we present the pre-processing steps up to the classification and detection of the urban objects. The modeling is not part of this work. The pre-processing steps described here cover briefly the coregistration of the input images and the generation of the DSM. In more detail the improvement of the DSM, the extraction of the DTM and nDEM, the multispectral classification and the object detection and extraction are explained. The methods described are applied to two test regions from two satellites: First the center of Munich acquired by WorldView-2 and second the center of Melbourne acquired by Pl´eiades. From both acquisitions a stereo-pair from the panchromatic bands is used for creation of the DSM and the pan-sharpened multispectral images are used for spectral classification. Finally the quality of the detected urban objects is discussed.

scholarly journals Evaluating digital terrain indices for soil wetness mapping – a Swedish case study

2014 ◽  
Vol 11 (4) ◽  
pp. 4103-4129 ◽  
Author(s):  
A. M. Ågren ◽  
W. Lidberg ◽  
M. Strömgren ◽  
J. Ogilvie ◽  
P. A. Arp
Keyword(s):  
Surface Flow ◽  
Topographic Wetness Index ◽  
Water Index ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Soil Disturbances ◽  
Soil Wetness ◽  
Elevation Model ◽  
Terrain Indices

Abstract. Driving with forestry machines on wet soils within and near stream and lake buffers can cause soil disturbances, i.e. rutting and compaction. This – in turn – can lead to increased surface flow, thereby facilitating the leaking of unwanted substances into downstream environments. Wet soils in mires, near streams and lakes have particularly low bearing capacity and are more susceptible to rutting. It is important to model and map the extent of these areas and associated wetness variations. This can be done with adequate reliability using high resolution digital elevation model (DEM). In this article, we report on several digital terrain indices to predict soil wetness by wet-area locations. We varied the resolution of these indices to test what scale produces the best possible wet-areas mapping conformance. We found that topographic wetness index (TWI) and the newly developed cartographic depth-to-water index (DTW) were the best soil wetness predictors. While the TWI derivations were sensitive to scale, the DTW derivations were not and were therefore numerically fairly robust. Since the DTW derivations vary by the area threshold used for setting stream flow initiation we found that the optimal threshold values varied by landform, e.g., 1–2 ha for till-derived landforms vs. 8 –16 ha for a coarse-textured alluvial floodplain.

scholarly journals Deteksi Kerawanan Banjir Genangan Menggunakan Topographic Wetness Index (TWI)

2018 ◽  
Vol 18 (2) ◽  
pp. 107
Author(s):  
Fitria Nucifera ◽  
Sutanto Trijuni Putro
Keyword(s):  
Digital Terrain Model ◽  
Topographic Wetness Index ◽  
Wetness Index ◽  
Terrain Model ◽  
Control Factors ◽  
Digital Terrain ◽  
Digital Elevation ◽  
High Flood ◽  
Elevation Model ◽  
Digital Elevation Model Data

Flood is the most frequent disaster occured in Indonesia. Flood events result in loss and damage to communities and the environment. Floods are triggered by several factors including hydrometeorological factors, topography, geology, soil and human activities. Topographic factor is one of the flood trigger control factors. Topographic calculation for flood inundation detection can be done by Topographic Wetness Index (TWI) method. The TWI method focuses on topographic conditions of the region, especially the upper slopes and lower slopes to assess the trend of water accumulation in a region. TWI calculations are based on the topography of an area represented by DEM (Digital Elevation Model) data in the form of DTM (Digital Terrain Model). The high value of TWI is associated with high flood vulnerability. Based on the calculation of TWI value, flood-prone areas in Kebumen District include Adimulyo Subdistrict, Puring Subdistrict, Ambal Subdistrict, Rowokele Subdistrict and Buayan Subdistrict.

scholarly journals Terrain-Based Shadow Correction Method for Assessing Supraglacial Features on the Greenland Ice Sheet

2021 ◽  
Vol 2 ◽  
Author(s):  
Sasha. Z. Leidman ◽  
Åsa K. Rennermalm ◽  
Richard G. Lathrop ◽  
Matthew. G. Cooper
Keyword(s):  
Land Surface ◽  
Greenland Ice Sheet ◽  
Correction Method ◽  
Correction Coefficient ◽  
Digital Elevation ◽  
Aerial Vehicle ◽  
Sediment Cover ◽  
Elevation Model ◽  
Uav Images ◽  
Gis Software

The presence of shadows in remotely sensed images can reduce the accuracy of land surface classifications. Commonly used methods for removing shadows often use multi-spectral image analysis techniques that perform poorly for dark objects, complex geometric models, or shaded relief methods that do not account for shadows cast on adjacent terrain. Here we present a new method of removing topographic shadows using readily available GIS software. The method corrects for cast shadows, reduces the amount of over-correction, and can be performed on imagery of any spectral resolution. We demonstrate this method using imagery collected with an uncrewed aerial vehicle (UAV) over a supraglacial stream catchment in southwest Greenland. The structure-from-motion digital elevation model showed highly variable topography resulting in substantial shadowing and variable reflectance values for similar surface types. The distribution of bare ice, sediment, and water within the catchment was determined using a supervised classification scheme applied to the corrected and original UAV images. The correction resulted in an insignificant change in overall classification accuracy, however, visual inspection showed that the corrected classification more closely followed the expected distribution of classes indicating that shadow correction can aid in identification of glaciological features hidden within shadowed regions. Shadow correction also caused a substantial decrease in the areal coverage of dark sediment. Sediment cover was highly dependent on the degree of shadow correction (k coefficient), yet, for a correction coefficient optimized to maximize shadow brightness without over-exposing illuminated surfaces, terrain correction resulted in a 49% decrease in the area covered by sediment and a 29% increase in the area covered by water. Shadow correction therefore reduces the overestimation of the dark surface coverage due to shadowing and is a useful tool for investigating supraglacial processes and land cover change over a wide variety of complex terrain.

scholarly journals Environmental classification of administrative units of the Ukrainian Carpathians

2014 ◽  
pp. 245-253
Author(s):  
Ivan Kruhlov
Keyword(s):  
Cluster Analysis ◽  
Standard Deviation ◽  
Satellite Images ◽  
Environmental Classification ◽  
Digital Elevation ◽  
Elevation Data ◽  
Digital Elevation Data ◽  
Administrative Units ◽  
Elevation Model

Boundaries of 43 administrative units (raions and oblast towns) were digitized and manually rectified using official schemes and satellite images. SRTM digital elevation data were used to calculate mean relative elevation and its standard deviation for each unit, as well as to delineate altitudinal bioclimatic belts and their portions within the units. These parameters were used to classify the units via agglomerative cluster analysis into nine environmental classes. Key words: cluster analysis, digital elevation model, geoecosystem, geo-spatial analysis.

The Coupling Relationship between Forest Vegetation and Terrain of Daliuta Mine

2014 ◽  
Vol 641-642 ◽  
pp. 1191-1194 ◽  
Author(s):  
Dong Wen Liu ◽  
Zhi Yong Qiao ◽  
Ting Ting Wei ◽  
Shu Jiang ◽  
Ya Kai Chen ◽  
...  
Keyword(s):  
Digital Terrain Model ◽  
Vegetation Coverage ◽  
Terrain Model ◽  
Digital Terrain ◽  
Digital Elevation ◽  
Object Use ◽  
Trend Data ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
Evolution Trend

Taking Daliuta mine as research object, use its 2002, 2011 two same period Landsat TM/ ETM and remote sensing image as the data source, use pixel dichotomy to get its vegetation coverage evolution trend data; Use DEM digital elevation model data in the region to generate digital terrain model based on ArcGIS, and make overlay analysis with the vegetation coverage evolution trend data to study the relationship between the vegetation coverage and terrain factor of the mine area. The results showed that: From 2002 to 2011, the vegetation coverage evolution trend of Daliuta mining mainly moderate improvement and significantly improvement, and concentrated in middle altitude, low slope, sunny area.

scholarly journals Digital soil mapping using multiple logistic regression on terrain parameters in southern Brazil

2006 ◽  
Vol 63 (3) ◽  
pp. 262-268 ◽  
Author(s):  
Elvio Giasson ◽  
Robin Thomas Clarke ◽  
Alberto Vasconcellos Inda Junior ◽  
Gustavo Henrique Merten ◽  
Carlos Gustavo Tornquist
Keyword(s):  
Land Use Planning ◽  
Soil Types ◽  
Sources Of Information ◽  
Topographic Wetness Index ◽  
Digital Elevation ◽  
Terrain Parameters ◽  
Logistic Regressions ◽  
Elevation Model ◽  
Soil Surveys ◽  
Soil Distribution

Soil surveys are necessary sources of information for land use planning, but they are not always available. This study proposes the use of multiple logistic regressions on the prediction of occurrence of soil types based on reference areas. From a digitalized soil map and terrain parameters derived from the digital elevation model in ArcView environment, several sets of multiple logistic regressions were defined using statistical software Minitab, establishing relationship between explanatory terrain variables and soil types, using either the original legend or a simplified legend, and using or not stratification of the study area by drainage classes. Terrain parameters, such as elevation, distance to stream, flow accumulation, and topographic wetness index, were the variables that best explained soil distribution. Stratification by drainage classes did not have significant effect. Simplification of the original legend increased the accuracy of the method on predicting soil distribution.

scholarly journals Quality of Digital Elevation Models obtained from Unmanned Aerial Vehicles for Precision Viticulture

OENO One ◽  
2016 ◽  
Vol 50 (3) ◽  
Author(s):  
Léo Pichon ◽  
Arnaud Ducanchez ◽  
Hélène Fonta ◽  
Bruno Tisseyre
Keyword(s):  
Low Cost ◽  
Wine Industry ◽  
Image Capture ◽  
Digital Elevation ◽  
Elevation Data ◽  
Aerial Vehicle ◽  
Elevation Model ◽  
Uav Images ◽  
Data Acquisition And Processing

<p style="text-align: justify;"><strong>Aims:</strong> This work aims to study the quality of low cost Digital Surface Models (DSMs) obtained with Unmanned Aerial Vehicle (UAV) images and to test whether these DSMs meet common requirements of the wine industry.</p><p style="text-align: justify;"><strong>Methods and results: </strong>Experiments were carried out on a 4-ha vineyard located 10 km north of Beziers (France). The experimental site presents slope and aspect variations representative of mechanised commercial vineyards in Languedoc Roussillon. DSMs were provided by three UAV companies selected for the diversity of their solutions in terms of image capture altitude, type of UAV and image processing software. DSMs were obtained by photogrammetry and correspond to commercial products usually delivered by UAV companies. DSMs from UAV were compared to a reference Digital Elevation Model (DEM) acquired by a laser tachymeter. Four indicators were used to test the quality of DSMs: the mean error and its dispersion in the XY plane and in elevation Z. Results show a good georeferencing of the DSMs (MeanErrorXY&lt;10 cm) and a similar quality in elevation (MeanErrorZ&lt;10 cm) estimation. Results also show that the error in elevation is highly spatially structured. The spatial patterns observed did not depend on the elevation and could be related to algorithms used to compute the DSMs.</p><p style="text-align: justify;"><strong>Conclusion: </strong>Data acquisition and processing methods have an impact on the quality of the DSMs provided by the UAV companies. DSM qualities are good enough to meet commercial vineyard requirements. The tested DSMs fit the requirements to assess field characteristics (elevation, slope, aspects) which may be important for terroir characterisation purposes.</p><p style="text-align: justify;"><strong>Significance and impact of the study:</strong> This study proves that elevation data derived from UAV present an accuracy equivalent to the reference system used in this study. The rapidity, the low cost and the high spatial resolution of these data offer significant opportunities for the development of new services for the wine industry for field characterisation.</p>

scholarly journals Extração de Atributos Morfométricos da Serra Mossoró (Mossoró-RN) a Partir do Modelo de Elevação Digital (MDE)

2020 ◽  
Vol 12 (6) ◽  
pp. 2239
Author(s):  
Gutemberg Henrique Dias ◽  
João Paulo Bezerra Rodrigues ◽  
Francisco Sérgio Coelho ◽  
Robson Fernandes Filgueira ◽  
Filipe Silva Peixoto
Keyword(s):  
Digital Elevation Model ◽  
Sedimentary Basin ◽  
Rio Grande ◽  
Field Observations ◽  
Accurate Calculation ◽  
Mapping Software ◽  
Potiguar Basin ◽  
Digital Elevation ◽  
Elevation Model

Por possibilitar o cálculo rápido e preciso de variáveis associadas ao relevo, nas últimas décadas, o aprimoramento do Modelo Digital de Elevação (MDE) tem contribuído bastante para a pesquisa geomorfológica, particularmente em áreas de bacias sedimentares. No setor noroeste da Bacia Potiguar, no município de Mossoró, estado do Rio Grande do Norte, existe uma elevação que se destaca em meio ao relevo plano, conhecida como Serra Mossoró. Apesar da importância da região no que se refere à exploração de água subterrânea, prospecção de petróleo e fruticultura tropical, os trabalhos já produzidos sobre esta forma de relevo são escassos e superficiais. Este trabalho tem como objetivo realizar a extração de atributos morfométricos da Serra Mossoró e de suas adjacências a partir de Modelo de Elevação Digital (MDE), de modo a precisar a classificação deste relevo e correlaciona-lo com a neotectônica regional. Pesquisa bibliográfica, tratamento de imagens orbitais georreferenciadas com software de mapeamento e observações de campo possibilitaram a elaboração dos mapas hipsométrico, de relevo sombreado (hillshade) e clinométrico. A análise dos dados hipsométricos evidencia que a Serra Mossoró está estruturada em patamares e rampas, apresentando altimetria máxima de 268 metros. O mapa de relevo sombreado confirma a ocorrência de lineamentos  nos sentidos NE-SW e NW-SE, bem como, em menor proporção, no E-O, já descritos em outros trabalhos. Juntos, os mapas hipsométrico e de relevo sombreado definem a estrutura da Serra Mossoró como um inselberg de natureza sedimentar, resultante da erosão diferencial nas rochas da Bacia Potiguar.  Extraction of Morphometric Attributes from Serra Mossoró (Mossoró-RN) From the Digital Elevation Model (MDE) A B S T R A C TFor enabliling a rapid and accurate calculation of the variables associated to relief, in the last decades the enhancement of the Digital Elevation Model (DEM) has contributed greatly to geomorphological research, particularly in sedimentary basin areas. In the northwestern section of the Potiguar Basin, in the municipality of Mossoró, state of Rio Grande do Norte, there is an elevation that stands out in the middle of the flat relief known as Serra Mossoró. Despite the importance of the region in the exploration of groundwater, oil prospecting and tropical fruiticulture, the works already produced on this landform are scarce and superficial. From the analysis of morphometric attributes, this work aims to produce the DEM of Serra Mossoró and its surroundings, in order to clarify the classification of this relief and correlate it with the regional neotectonics. Bibliographical research, treatment of georeferenced orbital images with mapping software and field observations enabled the elaboration of the hypsometric, hillshade and clinometrical. The analysis of hypsometric data shows that Serra Mossoró is structured in steps and ramps, with a maximum altimetry of 268 meters. The hillshade map confirm the occurrence of lineaments in the NE-SW and NW-SE directions, as well as, to a lesser extent, in the E-O direction, already described in other works. Together, the hypsometric and hillshade maps define the Serra Mossoró structure as a sedimentary inselberg resulting from differential erosion in the rocks of the Potiguar Basin. Key words: Serra Mossoró, geologic-geomorphologic mapping, morphometric attributes, Digital Elevation Model

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