E. O. Makinde, A. Salami, J. Olaleye, Oluwapelumi Comfort Okewusi
Several studies have been carried out to find an appropriate method to classify the remote sensing data. Traditional classification approaches are all pixel-based, and do not utilize the spatial information within an object which is an important source of information to image classification. Thus, this study compared the pixel based and object based classification algorithms using RapidEye satellite image of Eti-Osa LGA, Lagos. In the object-oriented approach, the image was segmented to homogenous area by suitable parameters such as scale parameter, compactness, shape etc. Classification based on segments was done by a nearest neighbour classifier. In the pixel-based classification, the spectral angle mapper was used to classify the images. The user accuracy for each class using object based classification were 98.31% for waterbody, 92.31% for vegetation, 86.67% for bare soil and 90.57% for Built up while the user accuracy for the pixel based classification were 98.28% for waterbody, 84.06% for Vegetation 86.36% and 79.41% for Built up. These classification techniques were subjected to accuracy assessment and the overall accuracy of the Object based classification was 94.47%, while that of Pixel based classification yielded 86.64%. The result of classification and accuracy assessment show that the object-based approach gave more accurate and satisfying results
为了找到一种合适的遥感数据分类方法，已经进行了一些研究。传统的分类方法都是基于像素的，没有利用物体内部的空间信息，而空间信息是图像分类的重要信息来源。因此，本研究利用拉各斯etii - osa LGA的RapidEye卫星图像，比较了基于像素和基于目标的分类算法。在面向对象的方法中，通过合适的尺度参数、紧凑度、形状等参数将图像分割成均匀的区域。基于片段的分类由最近邻分类器完成。在基于像素的分类中，使用光谱角度映射器对图像进行分类。水体、植被、裸土和Built - up分类的用户准确率分别为98.31%、92.31%、86.67%和90.57%，而像元分类的用户准确率分别为98.28%、84.06%、86.36%和79.41%。对这些分类技术进行了准确率评估，基于目标的分类总体准确率为94.47%，而基于像素的分类总体准确率为86.64%。分类和准确率评估结果表明，基于对象的分类方法具有更高的准确率和令人满意的结果
{"title":"Object Based and Pixel Based Classification Using Rapideye Satellite Imager of ETI-OSA, Lagos, Nigeria","authors":"E. O. Makinde, A. Salami, J. Olaleye, Oluwapelumi Comfort Okewusi","doi":"10.14311/GI.15.2.5","DOIUrl":"https://doi.org/10.14311/GI.15.2.5","url":null,"abstract":"Several studies have been carried out to find an appropriate method to classify the remote sensing data. Traditional classification approaches are all pixel-based, and do not utilize the spatial information within an object which is an important source of information to image classification. Thus, this study compared the pixel based and object based classification algorithms using RapidEye satellite image of Eti-Osa LGA, Lagos. In the object-oriented approach, the image was segmented to homogenous area by suitable parameters such as scale parameter, compactness, shape etc. Classification based on segments was done by a nearest neighbour classifier. In the pixel-based classification, the spectral angle mapper was used to classify the images. The user accuracy for each class using object based classification were 98.31% for waterbody, 92.31% for vegetation, 86.67% for bare soil and 90.57% for Built up while the user accuracy for the pixel based classification were 98.28% for waterbody, 84.06% for Vegetation 86.36% and 79.41% for Built up. These classification techniques were subjected to accuracy assessment and the overall accuracy of the Object based classification was 94.47%, while that of Pixel based classification yielded 86.64%. The result of classification and accuracy assessment show that the object-based approach gave more accurate and satisfying results","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114138014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Measurand MEMS ShapeAccelArray sensors are in many ways unique and new equipment, which allows to determine the relative displacements and deformations in other ways than before. The instruments are described, tested and compared with existing instrumentation in a small number of articles, but with exception of one it was not tested from engineering surveying point of view, where the exact precision and accuracy knowledge is a basis for the further use. The result of the experiments is the accuracy of measuring changes by the sensor itself, the pros and cons of its use and some features of its design, which is good to know before using it. There were designed and performed practical tests to determine the relative and absolute measurement accuracy of the sensor deformations measurement in all three possible types of use, namely the vertical installation, the horizontal installation and the measurement of convergence. The results show high accuracy of the sensor tested, which is under certain conditions even considerably higher than that given by Measurand
{"title":"Test of the Precision and Accuracy of the ShapeAccelArray Sensor","authors":"M. Štroner, R. Urban, J. Balek","doi":"10.14311/GI.15.2.4","DOIUrl":"https://doi.org/10.14311/GI.15.2.4","url":null,"abstract":"Measurand MEMS ShapeAccelArray sensors are in many ways unique and new equipment, which allows to determine the relative displacements and deformations in other ways than before. The instruments are described, tested and compared with existing instrumentation in a small number of articles, but with exception of one it was not tested from engineering surveying point of view, where the exact precision and accuracy knowledge is a basis for the further use. The result of the experiments is the accuracy of measuring changes by the sensor itself, the pros and cons of its use and some features of its design, which is good to know before using it. There were designed and performed practical tests to determine the relative and absolute measurement accuracy of the sensor deformations measurement in all three possible types of use, namely the vertical installation, the horizontal installation and the measurement of convergence. The results show high accuracy of the sensor tested, which is under certain conditions even considerably higher than that given by Measurand","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"181 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133543745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper deals with a tool that enables import of the coded data in a single text file to more than one vector layers (including attribute tables), together with automatic drawing of line and polygon objects and with optional conversion to CAD. Python script v.in.survey is available as an add-on for open-source software GRASS GIS (GRASS Development Team). The paper describes a case study based on surveying at the archaeological mission at Tell-el Retaba (Egypt). Advantages of the tool (e.g. significant optimization of surveying work) and its limits (demands on keeping conventions for the points’ names coding) are discussed here as well. Possibilities of future development are suggested (e.g. generalization of points’ names coding or more complex attribute table creation).
{"title":"Open-source tool for automatic import of coded surveying data to multiple vector layers in GIS environment","authors":"Eva Stopková","doi":"10.14311/GI.15.2.2","DOIUrl":"https://doi.org/10.14311/GI.15.2.2","url":null,"abstract":"This paper deals with a tool that enables import of the coded data in a single text file to more than one vector layers (including attribute tables), together with automatic drawing of line and polygon objects and with optional conversion to CAD. Python script v.in.survey is available as an add-on for open-source software GRASS GIS (GRASS Development Team). The paper describes a case study based on surveying at the archaeological mission at Tell-el Retaba (Egypt). Advantages of the tool (e.g. significant optimization of surveying work) and its limits (demands on keeping conventions for the points’ names coding) are discussed here as well. Possibilities of future development are suggested (e.g. generalization of points’ names coding or more complex attribute table creation).","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121164758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A geodetic measurement of shifts and deformations by total station is a well-known and widely used method. There is presented the analysis of the variations over time of the measured values in continuous geodetic monitoring in this paper. There are used measured data from a specific monitoring system of a surface mine in the time period from January 2006 to July 2010 in the analysis. The aim of the analysis is to describe linear trend and periodic changes in measured data (horizontal direction, zenith angle and slope distance). The main method of the analysis is a linear-harmonic function approximation.
{"title":"Analysis of the variations of measured values in continuous long-term geodetic monitoring","authors":"J. Vaněček","doi":"10.14311/GI.15.1.2","DOIUrl":"https://doi.org/10.14311/GI.15.1.2","url":null,"abstract":"A geodetic measurement of shifts and deformations by total station is a well-known and widely used method. There is presented the analysis of the variations over time of the measured values in continuous geodetic monitoring in this paper. There are used measured data from a specific monitoring system of a surface mine in the time period from January 2006 to July 2010 in the analysis. The aim of the analysis is to describe linear trend and periodic changes in measured data (horizontal direction, zenith angle and slope distance). The main method of the analysis is a linear-harmonic function approximation.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121197688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Potůčková, L. Červená, L. Kupková, Z. Lhotáková, J. Albrechtová
The physiological status of vegetation and changes thereto can be monitored by means of biochemical analysis of collected samples as well as by means of spectroscopic measurements either on the leaf level, using field (or laboratory) spectroradiometers or on the canopy level, applying hyperspectral airborne or spaceborne image data. The presented study focuses on the statistical comparison and ascertainment of relations between three datasets collected from selected Norway spruce forest stands in the Ore Mountains, Czechia. The data sets comprise i) photosynthetic pigments (chlorophylls, carotenoids) and water content of 495 samples collected from 55 trees from three different vertical levels and the first three needle age classes, ii) the spectral reflectance of the same samples measured with an ASD Field Spec 4 Wide-Res spectroradiometer equipped with a plant contact probe, iii) an airborne hyperspecral image acquired with an Apex sensor. The datasets cover two localities in the Ore Mountains that were affected differently by acid deposits in the 1970s and 1980s. A one-way analysis of variance (ANOVA), Tukey’s honest significance test, hot spot analysis and linear regression were applied either on the original measurements (the content of leaf compounds and reflectance spectra) or derived values, i.e., selected spectral indices. The results revealed a generally low correlation between the photosynthetic pigments, water content and spectral measurement. The results of the ANOVA showed significant differences between sites (model areas) only in the case of the leaf compound dataset. Differences between the stands on various levels of significance exist in all three datasets and are explained in detail. The study also proved that the vertical gradient of the biochemical and biophysical parameters in the canopy play a role when the optical properties of the forest stands are modelled.
植被的生理状态及其变化可以通过对收集的样品进行生化分析以及在叶片水平上使用野外(或实验室)光谱仪或在冠层水平上使用高光谱机载或星载图像数据进行光谱测量来监测。提出的研究侧重于统计比较和确定三个数据集之间的关系，这些数据集收集自选定的挪威云杉林，捷克山脉。数据集包括i)光合色素(叶绿素，类胡萝卜素)和水分含量，从55棵树的三个不同的垂直水平和前三个针龄类别中收集的495个样本，ii)使用配备植物接触探针的ASD Field Spec 4宽分辨率光谱辐射计测量相同样本的光谱反射率，iii)使用Apex传感器获得的航空高光谱图像。这些数据集涵盖了20世纪70年代和80年代受酸性矿床影响不同的矿石山两个地区。采用单因素方差分析(ANOVA)、Tukey’s honest显著性检验、热点分析和线性回归对原始测量值(叶片化合物含量和反射率光谱)或衍生值(即选定的光谱指标)进行分析。结果表明，光合色素、水分含量与光谱测量之间的相关性一般较低。方差分析的结果显示，只有在树叶化合物数据集的情况下，不同地点(模型区域)之间存在显著差异。在所有三个数据集中存在不同程度的显著性差异，并进行了详细解释。研究还证明，在模拟林分光学特性时，林冠中生化和生物物理参数的垂直梯度会起作用。
{"title":"Statistical comparison of spectral and biochemical measurements on an example of Norway spruce stands in the Ore Mountains, Czech Republic","authors":"M. Potůčková, L. Červená, L. Kupková, Z. Lhotáková, J. Albrechtová","doi":"10.14311/GI.15.1.6","DOIUrl":"https://doi.org/10.14311/GI.15.1.6","url":null,"abstract":"The physiological status of vegetation and changes thereto can be monitored by means of biochemical analysis of collected samples as well as by means of spectroscopic measurements either on the leaf level, using field (or laboratory) spectroradiometers or on the canopy level, applying hyperspectral airborne or spaceborne image data. The presented study focuses on the statistical comparison and ascertainment of relations between three datasets collected from selected Norway spruce forest stands in the Ore Mountains, Czechia. The data sets comprise i) photosynthetic pigments (chlorophylls, carotenoids) and water content of 495 samples collected from 55 trees from three different vertical levels and the first three needle age classes, ii) the spectral reflectance of the same samples measured with an ASD Field Spec 4 Wide-Res spectroradiometer equipped with a plant contact probe, iii) an airborne hyperspecral image acquired with an Apex sensor. The datasets cover two localities in the Ore Mountains that were affected differently by acid deposits in the 1970s and 1980s. A one-way analysis of variance (ANOVA), Tukey’s honest significance test, hot spot analysis and linear regression were applied either on the original measurements (the content of leaf compounds and reflectance spectra) or derived values, i.e., selected spectral indices. The results revealed a generally low correlation between the photosynthetic pigments, water content and spectral measurement. The results of the ANOVA showed significant differences between sites (model areas) only in the case of the leaf compound dataset. Differences between the stands on various levels of significance exist in all three datasets and are explained in detail. The study also proved that the vertical gradient of the biochemical and biophysical parameters in the canopy play a role when the optical properties of the forest stands are modelled.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"42 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134235211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Klokočník, Jiří Sonnek, K. Hanzalová, K. Pavelka
The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011) in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials) and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS) of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too), thus supporting (but surely not proving) the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca) means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.
{"title":"Hypotheses about geoglyphs at Nasca, Peru: new discoveries","authors":"J. Klokočník, Jiří Sonnek, K. Hanzalová, K. Pavelka","doi":"10.14311/GI.15.1.7","DOIUrl":"https://doi.org/10.14311/GI.15.1.7","url":null,"abstract":"The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011) in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials) and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS) of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too), thus supporting (but surely not proving) the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca) means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129316143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In aerial photogrammetry, the Cartesian coordinate system for the description of object space is commonly used. In contrast, many projects have to be processed in the space combined by the composition of a map projection and Vertical datum. In that space, some geometric deformations exist. There are some compensative methods for active and passive sensors. In the case of active sensors, decomposition and the correction of observation vector for each ground point can be used. We obtain height, horizontal distance and horizontal angle in this process. All of these values should be corrected for precise georeferencing. The contribution deals with the derivation of the corrections and gets some theoretical values from the area of the Czech Republic.
{"title":"Direct georeferencing with correction of map projection distortions for active imaging","authors":"Z. Švec","doi":"10.14311/GI.15.1.3","DOIUrl":"https://doi.org/10.14311/GI.15.1.3","url":null,"abstract":"In aerial photogrammetry, the Cartesian coordinate system for the description of object space is commonly used. In contrast, many projects have to be processed in the space combined by the composition of a map projection and Vertical datum. In that space, some geometric deformations exist. There are some compensative methods for active and passive sensors. In the case of active sensors, decomposition and the correction of observation vector for each ground point can be used. We obtain height, horizontal distance and horizontal angle in this process. All of these values should be corrected for precise georeferencing. The contribution deals with the derivation of the corrections and gets some theoretical values from the area of the Czech Republic.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"630 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123347566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iconographic sources depicting Thirty Years’ War battlefields in the Czech lands can be found in historical graphic works printed in the most comprehensive documentary publication of the 17 th century, the Theatrum Europaeum. In this publication, the year 1647 is one of the richest in terms of the number of engravings depicting the course of the war. In addition, the Swedish campaign of the same year left behind the most numerous and best preserved traces in the landscape of the Czech lands. The paper focuses primarily on engravings related to war events at the locations of Cheb, Třebel and Tepla. It presents interim results of interdisciplinary research of these iconographic sources, which involves the tools of spatial analyses, digital terrain modelling and also new possibilities of airborne laser scanning data processing. The main aims of the research, which are also being implemented, are the confirmation of depicted localities and their localization; analyses of the scale and geometrical precision of displayed landscape; estimates of visibility and methods of creating the source materials for engravings; and a detailed comparison with other contemporary or current cartographic sources.
{"title":"Using GIS and methods of digital cartography for analyzing battlefield engravings of 17th century","authors":"Tomás Janata, R. Zimová","doi":"10.14311/GI.15.1.4","DOIUrl":"https://doi.org/10.14311/GI.15.1.4","url":null,"abstract":"Iconographic sources depicting Thirty Years’ War battlefields in the Czech lands can be found in historical graphic works printed in the most comprehensive documentary publication of the 17 th century, the Theatrum Europaeum. In this publication, the year 1647 is one of the richest in terms of the number of engravings depicting the course of the war. In addition, the Swedish campaign of the same year left behind the most numerous and best preserved traces in the landscape of the Czech lands. The paper focuses primarily on engravings related to war events at the locations of Cheb, Třebel and Tepla. It presents interim results of interdisciplinary research of these iconographic sources, which involves the tools of spatial analyses, digital terrain modelling and also new possibilities of airborne laser scanning data processing. The main aims of the research, which are also being implemented, are the confirmation of depicted localities and their localization; analyses of the scale and geometrical precision of displayed landscape; estimates of visibility and methods of creating the source materials for engravings; and a detailed comparison with other contemporary or current cartographic sources.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115160115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are several options how to configure Web Map Service using several map servers. GeoServer is one of most popular map servers nowadays. GeoServer is able to read data from several sources. Very popular data source is ESRI Shapefile. It is well documented and most of software for geodata processing is able to read and write data in this format. Another very popular data store is PostgreSQL/PostGIS object-relational database. Both data sources has advantages and disadvantages and user of GeoServer has to decide which one to use. The paper describes comparison of performance of GeoServer Web Map Service when reading data from ESRI Shapefile or from PostgreSQL/PostGIS database.
使用多个地图服务器配置Web地图服务有几种选择。GeoServer是当今最流行的地图服务器之一。GeoServer能够从多个数据源读取数据。非常流行的数据源是ESRI Shapefile。它有很好的文档，大多数用于地理数据处理的软件都能够以这种格式读取和写入数据。另一个非常流行的数据存储是PostgreSQL/PostGIS对象关系数据库。这两种数据源各有优缺点，GeoServer的用户必须决定使用哪一个。本文比较了GeoServer Web Map Service从ESRI Shapefile和PostgreSQL/PostGIS数据库中读取数据时的性能。
{"title":"Comparing speed of Web Map Service with GeoServer on ESRI Shapefile and PostGIS","authors":"J. Růžička","doi":"10.14311/GI.15.1.1","DOIUrl":"https://doi.org/10.14311/GI.15.1.1","url":null,"abstract":"There are several options how to configure Web Map Service using several map servers. GeoServer is one of most popular map servers nowadays. GeoServer is able to read data from several sources. Very popular data source is ESRI Shapefile. It is well documented and most of software for geodata processing is able to read and write data in this format. Another very popular data store is PostgreSQL/PostGIS object-relational database. Both data sources has advantages and disadvantages and user of GeoServer has to decide which one to use. The paper describes comparison of performance of GeoServer Web Map Service when reading data from ESRI Shapefile or from PostgreSQL/PostGIS database.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122665680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reprojecting raster maps from one projection to another is an essential part of many cartographic processes (map comparison, overlays, data presentation, ...) and reducing the required computational time is desirable and often significantly decreases overall processing costs. The raster reprojection process operates per-pixel and is, therefore, a good candidate for GPU-based parallelization where the large number of processors can lead to a very high degree of parallelism. We have created an experimental implementation of the raster reprojection with GPU-based parallelization (using OpenCL API). During the evaluation, we compared the performance of our implementation to the optimized GDAL and showed that there is a class of problems where GPU-based parallelization can lead to more than sevenfold speedup.
{"title":"GPU-accelerated raster map reprojection","authors":"Petr Sloup","doi":"10.14311/GI.15.1.5","DOIUrl":"https://doi.org/10.14311/GI.15.1.5","url":null,"abstract":"Reprojecting raster maps from one projection to another is an essential part of many cartographic processes (map comparison, overlays, data presentation, ...) and reducing the required computational time is desirable and often significantly decreases overall processing costs. The raster reprojection process operates per-pixel and is, therefore, a good candidate for GPU-based parallelization where the large number of processors can lead to a very high degree of parallelism. We have created an experimental implementation of the raster reprojection with GPU-based parallelization (using OpenCL API). During the evaluation, we compared the performance of our implementation to the optimized GDAL and showed that there is a class of problems where GPU-based parallelization can lead to more than sevenfold speedup.","PeriodicalId":436054,"journal":{"name":"Geoinformatics FCE CTU","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124886703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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