scholarly journals Impact of the use of existing ditch vector data on soil moisture predictions

2020 ◽  
Author(s):  
Janis Ivanovs ◽  
◽  
Toms Stals ◽  
Santa Kaleja ◽  
◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Runoff ◽  
Vector Data ◽  
Geospatial Information ◽  
Digital Elevation ◽  
Close Proximity ◽  
Open Source Gis ◽  
Soil Wetness ◽  
Forest Lands ◽  
Gis Software

Wet soils play an important role in hydrological, biological and chemical processes, and knowledge on their spatial distribution is essential in forestry, agriculture and similar fields. Digital elevation models (DEM) and various hydrological indexes are used to perform water runoff and accumulation processes. The prerequisite for the calculation of the hydrological indexes is the most accurate representation of the Earth’s surface in the DEM, which must be corrected as necessary to remove surface artifacts that create a dam effect. In addition, different resolutions for DEM give different results, so it is necessary to evaluate what resolution data is needed for a particular study. The aim of this study is to evaluate the feasibility of using existing ditch vector data for DEM correction and the resulting implications for soil moisture prediction. Applied methodology uses a network of available ditch vectors and creates gaps in the overlapping parts of the DEM. The data were processed using open source GIS software QGIS, GRASS GIS and Whitebox GAT. Ditch vector data were obtained from JSC Latvian State Forests and the Latvian Geospatial Information Agency. The results show that by applying the bottomless ditch approach in forest lands on moraine deposits, depending on the accuracy of the ditch vector data, the values of the prediction of the soil wetness both increase and decrease. On the other hand, in forest lands on graciolimnic sediments it is visible that predicted soil wetness values increase in the close proximity of ditches. For forest lands on glaciofluvial and eolitic sediments there were no visible changes because of lack of ditches.

scholarly journals Lifelong training program on QGIS tools for earth observation sciences in south-east Europe

2021 ◽  
Vol 12 (3) ◽  
pp. 88-102
Author(s):  
Bashkim IDRIZI ◽  
◽  
Lyubka PASHOVA ◽  
Pal NIKOLLI ◽  
◽  
...  
Keyword(s):  
Open Source ◽  
Earth Observation ◽  
Geospatial Information ◽  
Digital Revolution ◽  
East Europe ◽  
South East Europe ◽  
Development Tools ◽  
Open Source Gis ◽  
Software Platforms ◽  
Gis Software

Earth Observation (EO) data are an indispensable source of useful geospatial information, which can be efficiently combined with other data within the latest released open-source QGIS software. This paper aims: i) to present a general overview of the QGIS EO plugins; ii) to promote the Lifelong Learning (LLL) courses for open-source QGIS software tools provided by the Geo-SEE Institute from Skopje; iii) to appreciate the advantages of open-source QGIS for developing and improving EO applications. The training objectives are to enhance the research, development tools and technologies of QGIS and stimulate the obtaining and disseminating knowledge to utilize the open-source GIS software. Furthermore, there is a growing need to increase the number of well-educated professionals on issues related to the EO sciences in South-East Europe (SEE), who are better prepared for the labor market in today's digital revolution by using QGIS tools and plugins combined with other related GIS software platforms provided by the OSGeo family.

scholarly journals Karizes and Current Prospects for Their Use in Kazakhstan

2021 ◽  
pp. 181-198
Author(s):  
A.K. Sultanbekova ◽  
◽  
A.V. Mitusov ◽  
A. Azami ◽  
J.M. Sagintayev ◽  
...  
Keyword(s):  
Irrigation System ◽  
Water Supply Systems ◽  
Arid Zones ◽  
Water Losses ◽  
Central Asian ◽  
Digital Elevation ◽  
Catchment Areas ◽  
Close Proximity ◽  
Elevation Model ◽  
Gis Software

The kariz (karez, qanat) represent one of the ancient water supply systems in arid zones. Natural collection of groundwater coming down from the mountains and its transportation to irrigated fields is the main advantage of the kariz systems. This article aims to introduce into the community of Central Asian hydrologists, hydrogeologists, and farmers the idea of the possibility of applying the kariz technologies and constructing them based on the experiences of neighboring countries and the ancient settlement of Sauran (Turkestan Region, Kazakhstan). Satellite imagery allowed identifying 3 (three) karizes around Sauran. The subsequent geomorphological analyses of the digital elevation model was carried out using the specialized ECO GIS-software. Further on, the maximum catchment areas (MCA) of mother wells (kariz beginning) were calculated. As the result, it was revealed that the target karizes themselves were located in the areas with low MCA. However, the mother wells were located in close proximity to the areas with high MCAs. 300 hectares was enough to collect groundwater to feed the entire irrigation system in ancient times. Modern examples from neighboring countries and the archaeological sites on the territory of Kazakhstan prove the possibility of using the kariz technology in current conditions. The introduction of this practice will allow introducing the foothill land in Southern Kazakhstan into agricultural circulation, as well as eliminating water losses due to evaporation during storage and transportation.

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 Potential of Digital Elevation Topographic Maps reveal the history of the region: comparing Those Maps with Marsh data in the early Meiji Period

2019 ◽  
Vol 1 ◽  
pp. 1-2
Author(s):  
Masatoshi Ideto ◽  
Yuki Kurisu ◽  
Hideyuki Toishigawa
Keyword(s):  
Social Life ◽  
Topographic Map ◽  
Thematic Maps ◽  
Geospatial Information ◽  
Meiji Period ◽  
Topographic Information ◽  
Digital Elevation ◽  
New Findings ◽  
History Of ◽  
The Relationship

<p><strong>Abstract.</strong> Landform of lowland is remains of the natural disasters and the history. Residents of this area are influenced of the landform with history of natural disaster. Therefore, there is an inseparable relationship between topography and social life. At Geospatial Information Authority of Japan (GSI), we are creating Thematic maps which clearly express topographic information. We also create, Thematic maps which distinguish the topography from the formation of the land. New findings can be obtained by considering these thematic maps in combination.</p><p> In this paper, we study the relationship between landform and history of Tokyo by comparing “Digital Elevation Topographic Map” and “Marsh data in the early Meiji Period”. (This early Meiji Period here is the 1880s.)</p>

scholarly journals A Comparison of Precise Fertilization Prescription Rates to a Conventional Approach Based on the Open Source GIS Software

Poljoprivreda ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 52-59
Author(s):  
Mladen Jurišić ◽  
◽  
Dorijan Radočaj ◽  
Ivan Plaščak ◽  
Irena Rapčan
Keyword(s):  
Open Source ◽  
Precision Agriculture ◽  
Spatial Interpolation ◽  
Crop Yields ◽  
Conventional Approach ◽  
Optimal Interpolation ◽  
Phosphorous Pentoxide ◽  
Open Source Gis ◽  
Prescription Rates ◽  
Gis Software

Fertilization is one of the most important components of precision agriculture, ensuring high and stable crop yields. The process of spatial interpolation of soil sample data is recognized as a reliable method of determining the prescription rates for precise fertilization. However, the application of a free open-source geographic information system (GIS) software was often overlooked in the process. In this study, a method of precise fertilization prescription map creation was developed using an open-source GIS software to enable a wider and cheaper availability of its application. The study area covered three independent locations in Osijek-Baranja County. A method was developed for the fertilization of sugar beet with phosphorous pentoxide, but its application is universal with regard to the crop type. An ordinary kriging was determined as an optimal interpolation method for spatial interpolation, with the mean RMSE of 1.8754 and R2of 0.6955. By comparing the precision fertilization prescription rates to a conventional approach, the differences of 4.1 kg ha-1 for Location 1, 15.8 kg ha-1 for Location 2, and 11.2 kg ha-1 for Location 3 were observed. These values indicate a general deficit in soil phosphorous pentoxide, and precise fertilization could ensure its optimal content in the future sowing seasons.

scholarly journals Construction of multi-scale grid for massive land survey data

2020 ◽  
Vol 206 ◽  
pp. 03018
Author(s):  
Jia Zhang ◽  
Xiulian Wang ◽  
Xiaotong Zhang ◽  
Xiaofei Bai ◽  
Qiang Chen
Keyword(s):  
Information Integration ◽  
Data Model ◽  
Spatiotemporal Data ◽  
Distributed Data ◽  
Data Organization ◽  
Vector Data ◽  
Grid Data ◽  
Geospatial Information ◽  
Multi Scale ◽  
Scale Grid

In the face of ever-growing and complex massive multi-source spatiotemporal data, the traditional vector data model is increasingly difficult to meet the needs of efficient data organization, management, calculation and analysis. Based on the simple and widely used geographic grid data organization model, this paper designs a technical method to convert vector data into multi-scale grid data, establishes a unified, standardized and seamless land spatial grid data model, and analyses the area accuracy of multi-scale grid data. Practice shows that the model can better meet the needs of multi-scale geospatial information integration and analysis, and it is easy to carry out distributed data processing, which provides technical support for the efficient organization, fusion and analysis of spatiotemporal data.

scholarly journals ELECTRICITY INFRASTRUCTURE PLANNING: EVALUATING SOLAR POTENTIAL ASSESSMENTS FOR INFORMAL SETTLEMENTS USING GRASS AND FREELY AVAILABLE DATA

2018 ◽  
Vol XLII-4/W8 ◽  
pp. 69-76
Author(s):  
L. Hassim ◽  
S. Coetzee ◽  
V. Rautenbach
Keyword(s):  
Informal Settlement ◽  
Informal Settlements ◽  
Urban Fringe ◽  
Safe Alternative ◽  
Open Source Gis ◽  
Basic Services ◽  
Alternative Sources ◽  
Gis Software ◽  
The City ◽  
Electricity Infrastructure

<p><strong>Abstract.</strong> Informal settlements, also known as slums or shanty towns, are characterised by rapid and unstructured expansion, poorly constructed buildings, and in some cases, they are on disputed land. Such settlements often lack basic services, such as electricity. As a result, informal settlement dwellers turn to hazardous alternative sources of energy, such as illegal electricity connections and paraffin. Solar power is a clean and safe alternative. However, informal settlements are often located on undesirable land on the urban fringe where the topography may hinder the use of solar energy. The high density of dwellings could also be a hindrance. Therefore, the solar potential needs to be assessed before any implementations are planned. Solar potential assessment functionality is generally available in geographic information system (GIS) products. The nature, cost and accessibility of datasets required for the assessment vary significantly. In this paper, we evaluate the results of solar potential assessments using GRASS (Geographic Resources Analysis Support System) for a number of different datasets. The assessments were done for two informal settlements in the City of Tshwane (South Africa): Alaska, which is nestled on a hill; and Phomolong, a densely populated settlement with a rather flat topography. The results show that solar potential assessments with open source GIS software and freely available data are feasible. This eliminates the need for lengthy and bureaucratic procurement processes and reduces the financial costs of assessing solar potential for informal settlements.</p>

Development of Assessment Criteria for Various Open Sources GIS Software Packages

2021 ◽  
pp. 398-412
Author(s):  
Shahriar Shams
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Assessment Criteria ◽  
Significant Development ◽  
Analysis And Design ◽  
Advantages And Disadvantages ◽  
Software Packages ◽  
Open Source Gis ◽  
Gis Software

There has been a significant development in the area of free and open source geospatial software. Research has flourished over the decades from vendor-dependent software to open source software where researchers are paying increasing attention to maximize the value of their data. It is often a difficult task to choose particular open source GIS (OGIS) software among a number of emerging OGIS software. It is important to characterise the projects according to some unified criteria. Each software has certain advantages and disadvantages and it is always time consuming to identify exactly which software to select for a specific purpose. This chapter focuses on the assessment criteria enabling developers, researchers, and GIS users to select suitable OGIS software to meet their requirements for analysis and design of geospatial application in multidisciplinary fields. This chapter highlights the importance of assessment criteria, followed by an explanation of each criteria and their significance with examples from existing OGIS software.

Why Open Source GIS Software Is Not For Me

Fisheries ◽  
2014 ◽  
Vol 39 (5) ◽  
pp. 217-217
Author(s):  
Thom Litts
Keyword(s):  
Open Source ◽  
Open Source Gis ◽  
Gis Software
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