map algebra
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Author(s):  
Diogo Yukio Uema ◽  
Renan Valério Eduvirgem ◽  
Fernando Luiz de Paula Santil

Environmental monitoring is essential for society to maintain balance with the environment, given this fact, several methods from the science of geoprocessing and remote sensing were created to assist in the task. The present work used the Universal Soil Loss Equation to verify the spatiality of laminar erosions in the municipalities of Mandaguaçu and Presidente Castelo Branco, both in Paraná, in addition to comparing their results with data from the Digital Vegetation Index (NDVI) to obtain relationships between the loss of soils and the development or lack of vegetation. The results identified several foci of laminar erosion in the study area, as a possible cause, soils from the highly erodible Caiuá Sandstone can be considered, as well as topographic factors of the EUPS LS factor. It should be noted that the use of digital tools, satellite images and map algebra is not essential for environmental monitoring studies.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259651
Author(s):  
Nam Shin Kim ◽  
Jin Yeol Cha ◽  
Chi Hong Lim

Landforms determine the locations of particular biological communities based on their components and spatial positions. This study hierarchically classified the topographic spaces serving as habitats for biological communities in the Korean Peninsula and established the habitat types that occur on the classified landform types. We classified landform types by applying cell-based modeling, map algebra, and spatial query techniques to spatial data, including digital elevation model (DEM), Sentinel 2 image, land use, and field survey data to model their ecological characteristics. Landforms were classified into four categories (designated Category 1 through 4) according to their spatial scale based on topographical characteristics such as mountains, plains, alluvial landforms, coastal landforms, islands, and special areas (Baekdudaegan, DMZ), which are found throughout the Korean Peninsula. The landforms of the Korean Peninsula were classified into 47 subcategories in Category 1, 16 in Category 2, 36 in Category 3, and 63 in Category 4. There were 62 main types of habitats that were classified based on their topographic spatial units, and there were 437 types of sub-habitats, for which soil weathering, biodiversity, and geodiversity were combined with the main habitat types. When factor analysis was conducted for the environmental factors used to determine the main and sub-habitats, the first primary components were temperature-related factors, followed by biodiversity, geodiversity, aspect, and slope. When the indicator species were analyzed by habitat type, indicator species diversity was high in Jeju Province, Gangwon Province, and Gaema Plateau. Based on these results, landform elements for species habit conservation were assigned conservation values and classified into (I) absolute conservation areas, (II) transition areas, and (III) areas for coexistence with humans. Topographic spaces are being degraded as biological habitats as a result of climate change and human development; our proposed classifications can be applied to the conservation of landforms and biodiversity.


Author(s):  
Cinthya Pinargote ◽  
Henry Pacheco

Precision agriculture allows to gain efficiency, sustainability and profitability, since it provides great benefits in reducing the environmental impact of agriculture, economic risks and at the same time contributes to controlling the vigor of crops and improving the quality of their yield. The objective of this research is to discriminate weeds within the corn crop, based on their spectral response. For this, the advanced EBEE SQ agricultural drone was used, with which multispectral images were captured through its Parrot Sequoia camera. The images were processed with software in Geographic Information Systems (GIS). With the multispectral bands, different vegetation indices were calculated such as NDVI, NDVIAS, NGRDI, NDRE, GNDVI, using map algebra tools in specialized programs. A supervised classification was applied to the different indices to discriminate the different land covers, which obtained a precision of 93% and a Kappa index of 0.93. The results allowed to clearly differentiate the coverage of crops, weeds and bare soil. The data showed that both early-growing and developed weeds occupy 38% of the crop area. With this information, it is possible to improve the planning of agronomic practices, adding the herbicide at the specific site of the weeds.


2021 ◽  
Vol 56 (3) ◽  
pp. 480-490
Author(s):  
Tatiane Camila Martins Silva ◽  
Ima Célia Guimarães Vieira ◽  
Marcelo Cordeiro Thalês

The goal of this study was to determine the anthropization evolution of the Guamá river basin in the years 2000, 2008 and 2018 by means of the Anthropic Transformation Index. Land use and cover maps were obtained from two databases, Project Mapbiomas (Brazilian Annual Land Use and Land Cover Mapping Project) and PRODES (Project for the Satellite Monitoring of the Brazilian Amazon Forest). The main classes defined in the mapping process are: forest, natural non-forest vegetation, agriculture and livestock farming, secondary vegetation, urban infrastructure, water and others. Secondary vegetation was considered as the area where the forest classes of Mapbiomas intersects with the deforested areas of PRODES, as determined by the map algebra operator. The expansion of agriculture and livestock farming achieved an increase of about 10%, while the forest was reduced in almost 10%. The Guamá river basin obtained an Anthropic Transformation Index of 4.44 in 2000, 5.04 in 2008 and 5.09 in 2018, going from a regular to a degraded state in 18 years. The occupation process caused major alterations in the natural components of the landscape over the course of 18 years, notably in the amount of forest. Protection of 35% of the remnant primary forest in the Guamá river basin is vital for the conservation of water resources vulnerable to changes in land use.


2021 ◽  
Author(s):  
Mónica Caniupán ◽  
Rodrigo Torres-Avilés ◽  
Tatiana Gutiérrez-Bunster ◽  
Manuel Lepe

2021 ◽  
Vol 13 (14) ◽  
pp. 7539
Author(s):  
Zaw Naing Tun ◽  
Paul Dargusch ◽  
DJ McMoran ◽  
Clive McAlpine ◽  
Genia Hill

Myanmar is one of the most forested countries of mainland Southeast Asia and is a globally important biodiversity hotspot. However, forest cover has declined from 58% in 1990 to 44% in 2015. The aim of this paper was to understand the patterns and drivers of deforestation and forest degradation in Myanmar since 2005, and to identify possible policy interventions for improving Myanmar’s forest management. Remote sensing derived land cover maps of 2005, 2010 and 2015 were accessed from the Forest Department, Myanmar. Post-classification change detection analysis and cross tabulation were completed using spatial analyst and map algebra tools in ArcGIS (10.6) software. The results showed the overall annual rate of forest cover loss was 2.58% between 2005 and 2010, but declined to 0.97% between 2010 and 2015. The change detection analysis showed that deforestation in Myanmar occurred mainly through the degradation of forest canopy associated with logging rather than forest clearing. We propose that strengthening the protected area system in Myanmar, and community participation in forest conservation and management. There needs to be a reduction in centralisation of forestry management by sharing responsibilities with local governments and the movement away from corruption in the timber trading industry through the formation of local-based small and medium enterprises. We also recommend the development of a forest monitoring program using advanced remote sensing and GIS technologies.


Author(s):  
Hayder Mohammed Issa

Abstract In this research, an analysis of site suitability and potential desalination capacity for an integrated concentrated solar power (CSP) and reverse osmosis (RO) system can be established to overcome water-energy nexus problems such as water supply shortage, fossil fuel carbon emission, and increasing power consumption in Khanaqin area, East Iraq. Regarding various environmental and economic criteria, the analysis employed different methods and tools: analytical hierarchy process (AHP) method, additive weighting method for location selection (SL), and kriging interpolation with map algebra spatial analysis tools in ArcGIS software. The chosen criteria were assessed by using the rating method, and then the relative weight of each criterion was determined. Site suitability assessment results showed that only 0.05% of the study area, represented by thirteen sites, was highly suitable for the integrated CSP-RO system. Considering higher potential desalination capacity of the integrated CSP-RO system, the number of suitable sites was further refined, therefore only two plant sites were suggested for optimum desalination capacity. The current study helps to quantify factors related to establishing and operating combined CSP and RO plant, which aid for further insight investigations on solar and water resources availability of similar systems for different areas around the world.


2021 ◽  
Author(s):  
Ricardo León ◽  
Christopher Rochelle ◽  
André Burnol ◽  
Carmen Julia Giménez- Moreno ◽  
Tove Nielsen ◽  
...  

<p>The Pan-European gas-hydrate relate GIS database of GARAH project has allowed assessing the susceptibility of seafloor areas affected by hydrate dissociation. This study has been applied as a first step for the hydrate related risk assessment along the European continental margins. Several factors and variables have been taken into account. They have been defined by their relationship with the presence of hydrates below seafloor and weighted depending on the confidence of finding hydrates in this site. The maximum weight (or confidence) has been given to the recovered samples of gas hydrates or hydrate-dissociation evidences such as degassing or liquation structures observed in gravity cores. Seismic indicators of the presence of gas hydrate or hydrocarbon seabed fluid flow such as BSR, blanking acoustic, amplitude anomalies or the presence of geological structures of seabed fluid flow in the neighbouring of the GHSZ have been weighted with a lower value. The theoretical gas hydrate stability zone (GHSZ) for a standard composition for biogenic gas has been taken into account as another control factor and constrain feature. Seafloor areas out of the theoretical GSHZ have been excluded as potential likelihood to be affected by hydrate dissociation processes. The base of GHSZ has been classified as a critical area for these dissociation processes.</p><p>The proposed methodology analyses the geological hazard by means of the susceptibility assessment, defined by the likelihood of occurrence of hydrate dissociation, collapses, crater-like depressions or submarine landslides over seafloor. The baseline scenario is that gas hydrate occurrence is only possible in seafloor areas where pressure (bathymetry) and seafloor temperature conditions are inside the theoretical GHSZ. Inside GHSZ, the occurrence of gas hydrate is directly related to the presence of its evidences (direct samples of hydrates) or indicators (eg. pore water and velocity anomalies, BSR, gas chimneys, among others), as well as the occurrence of hydrocarbon fluid flow structures inside GHSZ. Finally, the likelihood of the seafloor to be affect gas hydrate dissociation processes will be major at the base of the GHSZ and in the neighbouring of the gas hydrate evidences and indicators. In order to proof this initial hypothesis, a susceptibility assessment has been carried out throughout map algebra in a GIS environment from a density map of evidences and indicators and the Pan-European map of the GHSZ over seafloor. Specifically, it has been conceived as a segmentation in three levels by quantiles resulting of the addition of the density map of evidences and indicators and the weighted map of the GHSZ over seafloor.</p><p> </p><p><strong>Acknowledgment</strong></p><p>GARAH project. GeoERA - GeoE.171.002</p>


2021 ◽  
Vol 13 (4) ◽  
pp. 716
Author(s):  
Àngela Puig-Sirera ◽  
Daniele Antichi ◽  
Dylan Warren Raffa ◽  
Giovanni Rallo

The work aimed to discriminate among different soil management treatments in terms of beneficial effects by high-resolution thermal and spectral vegetation imagery using an unmanned aerial vehicle and open-source GIS software. Five soil management treatments were applied in two organic vineyards (cv. Sangiovese) from Chianti Classico terroir (Tuscany, Italy) during two experimental years. The treatments tested consisted of conventional tillage, spontaneous vegetation, pigeon bean (Vicia faba var. minor Beck) incorporated in spring, mixture of barley (Hordeum vulgare L.) and clover (Trifolium squarrosum L.) incorporated or left as dead mulch in late spring. The images acquired remotely were analyzed through map-algebra and map-statistics in QGIS and correlated with field ecophysiological measurements. The surface temperature, crop water stress index (CWSI) and normalized difference vegetation index (NDVI) of each vine row under treatments were compared based on frequency distribution functions and statistics descriptors of position. The spectral vegetation and thermal-based indices were significantly correlated with the respective leaf area index (R2 = 0.89) and stem water potential measurements (R2 = 0.59), and thus are an expression of the crop vigor and water status. The gravel and active limestone soil components determined the spatial variability of vine biophysical (e.g., canopy vigor) and physiological characteristics (e.g., vine chlorophyll content) in both farms. The vine canopy surface temperature, and CWSI were lower on the spontaneous and pigeon bean treatments in both farms, thus evidencing less physiological stress on the vine rows derived from the cover crop residual effect. In conclusion, the proposed methodology showed the capacity to discriminate across soil management practices and map the spatial variability within vineyards. The methodology could serve as a simple and non-invasive tool for precision soil management in rainfed vineyards to guide producers on using the most efficient and profitable practice.


2021 ◽  
Vol 253 ◽  
pp. 108905
Author(s):  
Manoela Sacchis Lopes ◽  
Bijeesh Kozhikkodan Veettil ◽  
Dejanira Lüderitz Saldanha

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