Pub Date : 2019-10-06DOI: 10.1590/s1982-21702019000400027
Gustavo Mansur, Luiz Danilo Damasceno Ferreira
The signal transmission and position quality obtained by GNSS positioning directly depends on the time control. The atomic clocks aboard the satellites are responsible for this control. In this research, the satellites clock errors of GPS are studied, using data from the pseudorange, the satellite semi-major axis and the correction parameters of the satellites’ clock errors found in the RINEX navigation and observation files. From these data, the satellites’ clock errors are calculated using the IGS mathematical model for rubidium and cesium clocks, and then an adjustment technique is applied in order to estimate the new parameters of the clock corrections. For cesium atomic clocks, the periodic part of the mathematical model was adapted. The correction parameters adjusted were applied in the IGS and the adapted model; finally, the results were compared with the IGS data from the clk_30s file. The experiments carried out show an improvement of 50 cm in the cesium satellites’ clock errors. In addition, the research concludes that the satellites’ clock errors do not depend on the station where the data were collected and the equipment’s antenna.
{"title":"ERROR BEHAVIOR OF ATOMIC CLOCKS ABOARD GPS SATELLITES","authors":"Gustavo Mansur, Luiz Danilo Damasceno Ferreira","doi":"10.1590/s1982-21702019000400027","DOIUrl":"https://doi.org/10.1590/s1982-21702019000400027","url":null,"abstract":"The signal transmission and position quality obtained by GNSS positioning directly depends on the time control. The atomic clocks aboard the satellites are responsible for this control. In this research, the satellites clock errors of GPS are studied, using data from the pseudorange, the satellite semi-major axis and the correction parameters of the satellites’ clock errors found in the RINEX navigation and observation files. From these data, the satellites’ clock errors are calculated using the IGS mathematical model for rubidium and cesium clocks, and then an adjustment technique is applied in order to estimate the new parameters of the clock corrections. For cesium atomic clocks, the periodic part of the mathematical model was adapted. The correction parameters adjusted were applied in the IGS and the adapted model; finally, the results were compared with the IGS data from the clk_30s file. The experiments carried out show an improvement of 50 cm in the cesium satellites’ clock errors. In addition, the research concludes that the satellites’ clock errors do not depend on the station where the data were collected and the equipment’s antenna.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48471045","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}
Pub Date : 2019-09-22DOI: 10.1590/s1982-21702019000400025
M. Albayrak, Kerem Halicioglu, M. Özlüdemir, Burak Basoglu, R. Deniz, Allison R. B. Tyler, M. M. Aref
The Digital Zenith Camera Systems (DZCSs) are dedicated astrogeodetic instruments used to obtain highly accurate astrogeodetic vertical deflection (VD) data. The first Turkish DZCS, the Astrogeodetic Camera System (ACSYS), was developed in Istanbul, Turkey in 2015. The ACSYS was capable of determining astrogeodetic VDs with an accuracy of ~0.3 arcseconds. However, it had some limitations in observation duration: because of the semi-automated mechanical design, levelling the system towards zenith was a time-consuming process. Since 2016, the ACSYS has been modernized through system upgrades and new technological components. In this paper, we describe the instrument design of the new DZCS—ACSYS2—observation procedures, evaluation of the test data and calculations of these data. The preliminary ACSYS2 astrogeodetic test observations were conducted at Istanbul Technical University (ITU) test station. The standard deviation results of the repeated observations reveal a VD measurement precision of ~0.3 arcseconds for both the North-South and East-West components. To investigate the accuracy of the system, a lightweight total station How to cite this article: AlBAYRAK, M.; HAlICIOğlU, K.; ÖZlüDEMIR, M. T.; BAşOğlU, B.; DENIZ, R.; TYlER, A. R. B.; AREF, M. M. The use of the automated digital zenith camera system in Istanbul for the determination of astrogeodetic vertical deflection. Bulletin of Geodetic Sciences. 25(4): e2019025, 2019. 2 The use of the automated digital zenith camera system in Istanbul... Bulletin of Geodetic Sciences, 25(4): e2019025, 2019 based-geodetic system—QDaedalus—was also used at the ITU test station. The comparison of the VDs data between ACSYS2 and QDaedalus system shows that the ACSYS2 can produce reliable VDs data.
{"title":"THE USE OF THE AUTOMATED DIGITAL ZENITH CAMERA SYSTEM IN ISTANBUL FOR THE DETERMINATION OF ASTROGEODETIC VERTICAL DEFLECTION","authors":"M. Albayrak, Kerem Halicioglu, M. Özlüdemir, Burak Basoglu, R. Deniz, Allison R. B. Tyler, M. M. Aref","doi":"10.1590/s1982-21702019000400025","DOIUrl":"https://doi.org/10.1590/s1982-21702019000400025","url":null,"abstract":"The Digital Zenith Camera Systems (DZCSs) are dedicated astrogeodetic instruments used to obtain highly accurate astrogeodetic vertical deflection (VD) data. The first Turkish DZCS, the Astrogeodetic Camera System (ACSYS), was developed in Istanbul, Turkey in 2015. The ACSYS was capable of determining astrogeodetic VDs with an accuracy of ~0.3 arcseconds. However, it had some limitations in observation duration: because of the semi-automated mechanical design, levelling the system towards zenith was a time-consuming process. Since 2016, the ACSYS has been modernized through system upgrades and new technological components. In this paper, we describe the instrument design of the new DZCS—ACSYS2—observation procedures, evaluation of the test data and calculations of these data. The preliminary ACSYS2 astrogeodetic test observations were conducted at Istanbul Technical University (ITU) test station. The standard deviation results of the repeated observations reveal a VD measurement precision of ~0.3 arcseconds for both the North-South and East-West components. To investigate the accuracy of the system, a lightweight total station How to cite this article: AlBAYRAK, M.; HAlICIOğlU, K.; ÖZlüDEMIR, M. T.; BAşOğlU, B.; DENIZ, R.; TYlER, A. R. B.; AREF, M. M. The use of the automated digital zenith camera system in Istanbul for the determination of astrogeodetic vertical deflection. Bulletin of Geodetic Sciences. 25(4): e2019025, 2019. 2 The use of the automated digital zenith camera system in Istanbul... Bulletin of Geodetic Sciences, 25(4): e2019025, 2019 based-geodetic system—QDaedalus—was also used at the ITU test station. The comparison of the VDs data between ACSYS2 and QDaedalus system shows that the ACSYS2 can produce reliable VDs data.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44204902","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}
Pub Date : 2019-09-17DOI: 10.1590/s1982-21702019000400024
A. Antunes, L. Delazari
People tend to lose their sense of direction in closed environments and the role of indoor maps is to assist the user in navigating in these spaces, through understanding the environment, identifying reference points or positioning. Among the several forms of achieving positioning in indoor environments, this research used the method based on image recognition through identification of QR-Code labels, because of their low cost, easy implementation, and because their accuracy is not affected by the environment. As such, this article presents the use of QR-Code markers affixed to possible reference points to determine user positioning in an indoor environment using a mobile device. This study seeks to discover which are the most appropriate sites for placing QR-Codes in an environment, by evaluating what reference points and what type thereof are most used in indoor environments. This study is therefore based on the hypothesis that if initial positioning is obtained only through reference points this is sufficient for users to orient themselves. Through analysis of the results obtained from navigation tasks done by users we were able to obtain data regarding elements most cited as references. The results show that people orient themselves in distinct ways in the same environment and use as their main reference points structural elements of the environment such as stairways, lifts, and decision-making points; in general structural reference points were those most used to support orientation and navigation.
{"title":"LANDMARKS EVALUATION WITH USE OF QR-CODE FOR POSITIONING INDOOR ENVIRONMENT","authors":"A. Antunes, L. Delazari","doi":"10.1590/s1982-21702019000400024","DOIUrl":"https://doi.org/10.1590/s1982-21702019000400024","url":null,"abstract":"People tend to lose their sense of direction in closed environments and the role of indoor maps is to assist the user in navigating in these spaces, through understanding the environment, identifying reference points or positioning. Among the several forms of achieving positioning in indoor environments, this research used the method based on image recognition through identification of QR-Code labels, because of their low cost, easy implementation, and because their accuracy is not affected by the environment. As such, this article presents the use of QR-Code markers affixed to possible reference points to determine user positioning in an indoor environment using a mobile device. This study seeks to discover which are the most appropriate sites for placing QR-Codes in an environment, by evaluating what reference points and what type thereof are most used in indoor environments. This study is therefore based on the hypothesis that if initial positioning is obtained only through reference points this is sufficient for users to orient themselves. Through analysis of the results obtained from navigation tasks done by users we were able to obtain data regarding elements most cited as references. The results show that people orient themselves in distinct ways in the same environment and use as their main reference points structural elements of the environment such as stairways, lifts, and decision-making points; in general structural reference points were those most used to support orientation and navigation.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41612961","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000200009
J. Monico, H. Marques, Ítalo Tsuchiya, Rogério Takeshi Oyama, W. Queiroz, Mauricio Cardoso de Souza, J. Wentz
The availability in real time of GNSS satellites orbits, clock corrections and code and phase biases provided the possibility of application of Real Time Precise Point Positioning (RTPPP). This paper presents the methodology concerning RTPPP and application to kinematic trajectories of airplane flight tests, but without using the carrier phase bias. So, it is PPP float solution. It requires RT positioning estimation, task that most of time presents certain difficulties due to loss of communication or of satellites during maneuvers of the airplane. However, if the corrections become unavailable for a certain period of time, the system starts using the ultra-rapid IGS orbits. The experiments were accomplished taking into account a case simulating RT and another in fact RT, but storing data and corrections for post processing. The PPP solutions obtained either simulating RT or in RT were compared against the PPP post processed solution that uses the final clock and orbit corrections. Then, statistics were generated to analyze the quality of both results. They were applied to kinematic trajectory that on average was 360 km/h, reaching about 600 km/h. The results provided accuracy better than the requisites for such cases which is of about 80 cm in height.
{"title":"REAL TIME PPP APPLIED TO AIRPLANE FLIGTHT TESTS","authors":"J. Monico, H. Marques, Ítalo Tsuchiya, Rogério Takeshi Oyama, W. Queiroz, Mauricio Cardoso de Souza, J. Wentz","doi":"10.1590/S1982-21702019000200009","DOIUrl":"https://doi.org/10.1590/S1982-21702019000200009","url":null,"abstract":"The availability in real time of GNSS satellites orbits, clock corrections and code and phase biases provided the possibility of application of Real Time Precise Point Positioning (RTPPP). This paper presents the methodology concerning RTPPP and application to kinematic trajectories of airplane flight tests, but without using the carrier phase bias. So, it is PPP float solution. It requires RT positioning estimation, task that most of time presents certain difficulties due to loss of communication or of satellites during maneuvers of the airplane. However, if the corrections become unavailable for a certain period of time, the system starts using the ultra-rapid IGS orbits. The experiments were accomplished taking into account a case simulating RT and another in fact RT, but storing data and corrections for post processing. The PPP solutions obtained either simulating RT or in RT were compared against the PPP post processed solution that uses the final clock and orbit corrections. Then, statistics were generated to analyze the quality of both results. They were applied to kinematic trajectory that on average was 360 km/h, reaching about 600 km/h. The results provided accuracy better than the requisites for such cases which is of about 80 cm in height.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000200009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45746536","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000200007
G. Jerez, D. Alves
Several approaches concerning the use in positioning of GNSS (Global Navigation Satellite Systems) can be considered: systems, applied methods and errors that can affect the signals. Following the GLONASS (GLObal NAvigation Satellite System) constellation reestablishment (2011), there was renewed interest in its use with GPS (Global Positioning System). Different possibilities are available concerning applied methods, such as the virtual reference station (VRS) concept (it is possible to obtain data for a virtual station that does not physically exist, using data from a network). One of the main sources of error related to the GNSS signal, is the ionosphere. Many studies have been developed aiming to evaluate GPS positioning quality and influences that can affect it, but there are still several investigation possibilities concerning GLONASS. In this context, this research is intended to assess the GPS/GLONASS virtual data positioning performance considering regions and periods with different ionospheric behavior. A high correlation between the results from virtual and real data (Pearson’s correlation coefficients around 0.8) was noticed. GPS/GLONASS data performance presented better mean squared error results compared to GPS alone (average 3D improvement was 45 cm - 49%). In addition, it was possible to verify ionosphere influence in the positioning error, taking into account station region and period of the year.
{"title":"GENERATION AND PERFORMANCE ANALYSIS OF GPS AND GLONASS VIRTUAL DATA FOR POSITIONING UNDER DIFFERENT IONOSPHERIC CONDITIONS","authors":"G. Jerez, D. Alves","doi":"10.1590/S1982-21702019000200007","DOIUrl":"https://doi.org/10.1590/S1982-21702019000200007","url":null,"abstract":"Several approaches concerning the use in positioning of GNSS (Global Navigation Satellite Systems) can be considered: systems, applied methods and errors that can affect the signals. Following the GLONASS (GLObal NAvigation Satellite System) constellation reestablishment (2011), there was renewed interest in its use with GPS (Global Positioning System). Different possibilities are available concerning applied methods, such as the virtual reference station (VRS) concept (it is possible to obtain data for a virtual station that does not physically exist, using data from a network). One of the main sources of error related to the GNSS signal, is the ionosphere. Many studies have been developed aiming to evaluate GPS positioning quality and influences that can affect it, but there are still several investigation possibilities concerning GLONASS. In this context, this research is intended to assess the GPS/GLONASS virtual data positioning performance considering regions and periods with different ionospheric behavior. A high correlation between the results from virtual and real data (Pearson’s correlation coefficients around 0.8) was noticed. GPS/GLONASS data performance presented better mean squared error results compared to GPS alone (average 3D improvement was 45 cm - 49%). In addition, it was possible to verify ionosphere influence in the positioning error, taking into account station region and period of the year.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000200007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49532204","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000S00001
G. G. Pessoa, Amilton Amorim, M. Galo, M. Galo
The extraction of information from point cloud is usually done after the application of classification methods based on the geometric characteristics of the objects. However, the classification of photogrammetric point clouds can be carried out using radiometric information combined with geometric information to minimize possible classification issues. With this in mind, this work proposes an approach to the classification of photogrammetric point cloud, generated by correspondence of aerial images acquired by Remotely Piloted Aircraft System (RPAS). The proposed approach for classifying photogrammetric point clouds consists of a pixel-supervised classification method, based on a decision tree. To achieve this, three data sets were used, one to define which attributes allow discrimination between the classes and the definition of the thresholds. Initially, several attributes were extracted based on a training sample. The average and standard deviation values for the attributes of each class extracted were used to guide the decision tree definition. The defined decision tree was applied to the other two point clouds to validate the approach and for thematic accuracy assessment. The quantitative analyses of the classifications based on kappa coefficient of agreement, applied to both validation areas, reached values higher than 0.938
{"title":"PHOTOGRAMMETRIC POINT CLOUD CLASSIFICATION BASED ON GEOMETRIC AND RADIOMETRIC DATA INTEGRATION","authors":"G. G. Pessoa, Amilton Amorim, M. Galo, M. Galo","doi":"10.1590/S1982-21702019000S00001","DOIUrl":"https://doi.org/10.1590/S1982-21702019000S00001","url":null,"abstract":"The extraction of information from point cloud is usually done after the application of classification methods based on the geometric characteristics of the objects. However, the classification of photogrammetric point clouds can be carried out using radiometric information combined with geometric information to minimize possible classification issues. With this in mind, this work proposes an approach to the classification of photogrammetric point cloud, generated by correspondence of aerial images acquired by Remotely Piloted Aircraft System (RPAS). The proposed approach for classifying photogrammetric point clouds consists of a pixel-supervised classification method, based on a decision tree. To achieve this, three data sets were used, one to define which attributes allow discrimination between the classes and the definition of the thresholds. Initially, several attributes were extracted based on a training sample. The average and standard deviation values for the attributes of each class extracted were used to guide the decision tree definition. The defined decision tree was applied to the other two point clouds to validate the approach and for thematic accuracy assessment. The quantitative analyses of the classifications based on kappa coefficient of agreement, applied to both validation areas, reached values higher than 0.938","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000S00001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41506698","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000200012
H. Marques, Rodrigo Gonçalves, Alex da Silva Araujo, P. Pereira, H. Queiroz
The geodetic shoreline positioning has socioeconomic importance due to decision-making support related to the coastal zone. The Pernambuco state, Brazil, has established a state law no. 14.258/2010 sanctioned as part of Coastal Zone Management State Policy. The state act no. 42.010/2015 enacted the baseline information for Pernambuco shoreline. Considering that the shoreline mapping benefits from GNSS positioning using relative or absolute methods, the absolute PPP was the choice for legislation support. Therefore, the aim of this work is to depict about the Pernambuco state law and analyze the kinematic PPP accuracy applied to shoreline monitoring in order to attend the state act. The relative GNSS method was adopted as reference to assess the PPP accuracy for the Pernambuco shoreline. The analyses for each sector involved approximately one hour of kinematic GNSS data and the results indicate horizontal positioning accuracy around 0.50 m after PPP convergence period. Several PPP re-initialization has been detected, however, points considered outliers are removed from the final product. For this reason, recommendations are provided to improve the positioning applied for coastal zone monitoring. Although, the carried out experiments shows that PPP can be adopted as a practical tool to support the Pernambuco Coastal Zone Management
{"title":"SHORELINE MONITORING BY GNSS-PPP AIMING TO ATTENDANCE THE LAW 14.258/2010 FROM PERNAMBUCO STATE, BRAZIL","authors":"H. Marques, Rodrigo Gonçalves, Alex da Silva Araujo, P. Pereira, H. Queiroz","doi":"10.1590/S1982-21702019000200012","DOIUrl":"https://doi.org/10.1590/S1982-21702019000200012","url":null,"abstract":"The geodetic shoreline positioning has socioeconomic importance due to decision-making support related to the coastal zone. The Pernambuco state, Brazil, has established a state law no. 14.258/2010 sanctioned as part of Coastal Zone Management State Policy. The state act no. 42.010/2015 enacted the baseline information for Pernambuco shoreline. Considering that the shoreline mapping benefits from GNSS positioning using relative or absolute methods, the absolute PPP was the choice for legislation support. Therefore, the aim of this work is to depict about the Pernambuco state law and analyze the kinematic PPP accuracy applied to shoreline monitoring in order to attend the state act. The relative GNSS method was adopted as reference to assess the PPP accuracy for the Pernambuco shoreline. The analyses for each sector involved approximately one hour of kinematic GNSS data and the results indicate horizontal positioning accuracy around 0.50 m after PPP convergence period. Several PPP re-initialization has been detected, however, points considered outliers are removed from the final product. For this reason, recommendations are provided to improve the positioning applied for coastal zone monitoring. Although, the carried out experiments shows that PPP can be adopted as a practical tool to support the Pernambuco Coastal Zone Management","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000200012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45490096","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000200008
Maria Engracinda dos Santos Ferreira, L. Delazari
Spatial relations are words used to describe the existing relationships between elements present in environments. In the Natural Language, that is, that of the representations present geographical spatial organizations often seen in the daily lives of individuals, the user when reporting their location, uses a significant amount of spatial relations. Consequently, one has the difficulty of defining which of these words are suited to be used in spatial descriptions, in the sense of transmitting spatial information in a clear and precise way. Aiming to foster research in this field, an experiment was carried out with volunteers natives Brazilian Portuguese language in which the use of five spatial relations denoting distances in qualitative terms was sought. The results obtained showed that, although they present similar understandings, the incorrect use of one of these spatial relations can transmit to the receiver of the message an erroneous spatial information. In addition, it was observed a tendency in choosing a specific spatial relation as the distance between the reference elements increases with each other.
{"title":"THE USE OF SPATIAL TERMS “NEAR”, “VERY NEAR, “NEXT TO”, “SIDE BY SIDE AND “NEARBY” IN THE DESCRIPTIONS OF SPATIAL CONFIGURATIONS","authors":"Maria Engracinda dos Santos Ferreira, L. Delazari","doi":"10.1590/S1982-21702019000200008","DOIUrl":"https://doi.org/10.1590/S1982-21702019000200008","url":null,"abstract":"Spatial relations are words used to describe the existing relationships between elements present in environments. In the Natural Language, that is, that of the representations present geographical spatial organizations often seen in the daily lives of individuals, the user when reporting their location, uses a significant amount of spatial relations. Consequently, one has the difficulty of defining which of these words are suited to be used in spatial descriptions, in the sense of transmitting spatial information in a clear and precise way. Aiming to foster research in this field, an experiment was carried out with volunteers natives Brazilian Portuguese language in which the use of five spatial relations denoting distances in qualitative terms was sought. The results obtained showed that, although they present similar understandings, the incorrect use of one of these spatial relations can transmit to the receiver of the message an erroneous spatial information. In addition, it was observed a tendency in choosing a specific spatial relation as the distance between the reference elements increases with each other.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000200008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45779573","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000200011
L. F. Martins, M. Schmidt, André Mendonça
Technical graphic representation presents problems concerning the reduction of dimensionality from 3D to 2D. AEC (architecture, engineering and construction) projects usually adopt the top view paradigm with two-dimensional orthogonal projection. Recently, three major changes in technical representation were the alteration of orthogonal projection into a three-dimensional perspective view, inclusion of oriented object programing as in BIM Building Information Model) and the interactions with AR (augmented reality). In this context, the present research evaluates the proposal of symbology based on color Hue as done in Cartography and the impact of three-dimensionality of the symbol in the identification of incompatibilities in a project of a residential building. An application of the visual variable color hue was proposed improve readability to representations and evaluations were performed with expert users, using representations in CAD 2D, BIM and AR in top and perspective views. Results indicate the color hue improve the cognitive process of read, interpret and find incompatibilities in civil projects, while the change of point of view contribute to interaction and manipulation in virtual environments. Both shows significance higher than 6% in ANOVA tests.
技术图形表示提出了有关从3D到2D降维的问题。AEC (architecture, engineering and construction)项目通常采用二维正交投影的顶视图范式。最近，技术表现的三个主要变化是将正交投影转变为三维透视视图，包括面向对象编程(如BIM建筑信息模型)以及与AR(增强现实)的交互。在此背景下，本研究评估了在制图中基于颜色色调的符号学建议，以及在住宅建筑项目中识别不兼容性时符号的三维性的影响。提出了一种视觉变量色调的应用，以提高表征的可读性，并与专家用户一起进行了评估，在CAD 2D中使用表征，在顶部和透视图中使用BIM和AR。结果表明，色调改善了土木工程中阅读、解释和发现不兼容的认知过程，而视角的变化有助于虚拟环境中的交互和操作。方差分析均显示显著性高于6%。
{"title":"GRAPHICAL REPRESENTATION ANALYSIS OF COMPLEMENTARY CIVIL PROJECTS USING \"CAD 2D\", \"BIM\" AND \"RA\" AND IDENTIFICATION OF INTERFERENCES","authors":"L. F. Martins, M. Schmidt, André Mendonça","doi":"10.1590/S1982-21702019000200011","DOIUrl":"https://doi.org/10.1590/S1982-21702019000200011","url":null,"abstract":"Technical graphic representation presents problems concerning the reduction of dimensionality from 3D to 2D. AEC (architecture, engineering and construction) projects usually adopt the top view paradigm with two-dimensional orthogonal projection. Recently, three major changes in technical representation were the alteration of orthogonal projection into a three-dimensional perspective view, inclusion of oriented object programing as in BIM Building Information Model) and the interactions with AR (augmented reality). In this context, the present research evaluates the proposal of symbology based on color Hue as done in Cartography and the impact of three-dimensionality of the symbol in the identification of incompatibilities in a project of a residential building. An application of the visual variable color hue was proposed improve readability to representations and evaluations were performed with expert users, using representations in CAD 2D, BIM and AR in top and perspective views. Results indicate the color hue improve the cognitive process of read, interpret and find incompatibilities in civil projects, while the change of point of view contribute to interaction and manipulation in virtual environments. Both shows significance higher than 6% in ANOVA tests.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000200011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43901793","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}
Pub Date : 2019-09-04DOI: 10.1590/S1982-21702019000S00003
S. Azevedo, Renan Furlan de Oliveira, Wallace Casaca, E. Silva
Different built-up structures usually lead to large regions covered by shadows, causing partial or total loss of information present in urban environments. In order to mitigate the presence of shadows while improving the urban target discrimination in multispectral images, this paper proposes an automated methodology for both detection and recovery of shadows. First, the image bands are preprocessed in order to highlight their most relevant parts. Secondly, a shadow detection procedure is performed by using morphological filtering so that a shadow mask is obtained. Finally, the reconstruction of shadow-occluded areas is accomplished by an image inpainting strategy. The experimental evaluation of our methodology was carried out in four study areas acquired from a WorldView-2 (WV-2) satellite scene over the urban area of Sao Paulo city. The experiments have demonstrated a high performance of the proposed shadow detection scheme, with an average overall accuracy up to 92%. Considering the results obtained by our shadow removal strategy, the pre-selected shadows were substantially recovered, as verified by visual inspections. Comparisons involving both VrNIR-BI and VgNIR-BI spectral indices computed from original and shadow-free images also attest the substantial gain in recovering anthropic targets such as streets, roofs and buildings initially damaged by shadows.
{"title":"DESHADOWING OF HIGH SPATIAL RESOLUTION IMAGERY APPLIED TO URBAN AREA DETECTION","authors":"S. Azevedo, Renan Furlan de Oliveira, Wallace Casaca, E. Silva","doi":"10.1590/S1982-21702019000S00003","DOIUrl":"https://doi.org/10.1590/S1982-21702019000S00003","url":null,"abstract":"Different built-up structures usually lead to large regions covered by shadows, causing partial or total loss of information present in urban environments. In order to mitigate the presence of shadows while improving the urban target discrimination in multispectral images, this paper proposes an automated methodology for both detection and recovery of shadows. First, the image bands are preprocessed in order to highlight their most relevant parts. Secondly, a shadow detection procedure is performed by using morphological filtering so that a shadow mask is obtained. Finally, the reconstruction of shadow-occluded areas is accomplished by an image inpainting strategy. The experimental evaluation of our methodology was carried out in four study areas acquired from a WorldView-2 (WV-2) satellite scene over the urban area of Sao Paulo city. The experiments have demonstrated a high performance of the proposed shadow detection scheme, with an average overall accuracy up to 92%. Considering the results obtained by our shadow removal strategy, the pre-selected shadows were substantially recovered, as verified by visual inspections. Comparisons involving both VrNIR-BI and VgNIR-BI spectral indices computed from original and shadow-free images also attest the substantial gain in recovering anthropic targets such as streets, roofs and buildings initially damaged by shadows.","PeriodicalId":55347,"journal":{"name":"Boletim De Ciencias Geodesicas","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1590/S1982-21702019000S00003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46974161","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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