This paper implements and evaluates experimentally a procedure for automatically georeferencing images acquired by unmanned aerial vehicles(UAV s) in the sense that ground control points(GCP) are not necessary. Since ...This paper implements and evaluates experimentally a procedure for automatically georeferencing images acquired by unmanned aerial vehicles(UAV s) in the sense that ground control points(GCP) are not necessary. Since the camera model is necessary for georeferencing, this paper also proposes a completely automatic procedure for collecting corner pixels in the model plane image to solve the camera calibration problem, i.e., to estimate the camera and the lens distortion parameters. The performance of the complete georeferencing system is evaluated with real flight data obtained by a typical UAV.展开更多
Addresses are important data for urban applications. About 80% of the information local authorities use have a geographic component that is generally related to addresses. Addressing systems efficiency depend on the q...Addresses are important data for urban applications. About 80% of the information local authorities use have a geographic component that is generally related to addresses. Addressing systems efficiency depend on the quality of addresses locators. There are several methods to collect data. Surveys from the field are essential: GPS and pre-printed maps can be used to achieve this goal. GPS surveys from the field may be a solution, but it remains practical only for limited areas. To insure an accepted accuracy, GPS methods need special considerations that are time and money consuming. For Casablanca’s addressing locators, an alternative approach was adopted to collect 400 000 points. It took two months, 200 operators and 3500 printed maps to cover a study area of1,226 km2. This paper is to develop an optimized approach based on automated procedure for reintegrating printed maps in a geographic information system (GIS). It saves georeferencing time from 5min to just seconds per document. It insures, more importantly, an accuracy that is between20 cmto1 mfor scales that are between 1/500 and 1/2500. It ensures maps’ integration, independently of base map and coordinates system by introducing the notion of Georeferencing Code (GC).展开更多
The usage of georeferencing as a search tool has suffered a massification after the diffusion of technologies developed by Google and Microsoft. In this context, problems related to the location of properties situated...The usage of georeferencing as a search tool has suffered a massification after the diffusion of technologies developed by Google and Microsoft. In this context, problems related to the location of properties situated on highways are becoming quite usual in Brazil, because properties registration in highway is permitted in the country and this invalidates the dynamics of the georeferencing process. Therefore, a growing number of geotechnology users which desire to localize properties on highways, find inaccurate or amiss geographical information. This research focus is to present an enumeration method for highway properties and, consequently, the possibility of a precise georeferencing. The presented method contributes to turning possible the precision of this georeferencing process and it will also be relevant for geotechnology diffusion considering its integration to geographic information systems which include geocoding tools.展开更多
The port of Callao is important for its varied historical and archaeological heritage,which includes several military buildings that were the main actors and witnesses of the colonial era of Peru(from the 16th century...The port of Callao is important for its varied historical and archaeological heritage,which includes several military buildings that were the main actors and witnesses of the colonial era of Peru(from the 16th century to the country’s independence from Spain early in the 19th century).Despite the studies that have been carried out on the basis of documents and some eventual archaeological excavations,the port’s main monument,namely,the Real Felipe Fortress,continues to hide very important information that could be used to understand the role that the fortress played in numerous historical events throughout the centuries.The main contribution of this study is the use of photogrammetry software and a Geographic Information System(GIS)to examine the Real Felipe Fortress.In this way,the nature of the atypical construction within the fortress is determined.As a result,it is possible to accurately establish the location of the defensive wall that surrounded the ancient city of Callao,as well as its first churches,whose records were lost after being destroyed by the 1746 earthquake and tsunami in Lima,the worst cataclysm registered in the history of Peru and South America.As a result,this study demonstrates that technology can be successfully used to establish and validate with great precision the existence of the location of churches that have been built in the port of Callao since the founding of Lima in the 16th century.Such identification allows architects,engineers and students who are interested in the history of monuments to discover hidden structures and buildings and carry out the necessary restoration and archaeological works,with the aim of recovering the history of the colonial architecture of Callao and other similar cities and ports worldwide.展开更多
Laser scanning can provide timely assessments of mine sites despite adverse challenges in the operational environment.Although there are several published articles on laser scanning,there is a need to review them in t...Laser scanning can provide timely assessments of mine sites despite adverse challenges in the operational environment.Although there are several published articles on laser scanning,there is a need to review them in the context of underground mining applications.To this end,a holistic review of laser scanning is presented including progress in 3D scanning systems,data capture/processing techniques and primary applications in underground mines.Laser scanning technology has advanced significantly in terms of mobility and mapping,but there are constraints in coherent and consistent data collection at certain mines due to feature deficiency,dynamics,and environmental influences such as dust and water.Studies suggest that laser scanning has matured over the years for change detection,clearance measurements and structure mapping applications.However,there is scope for improvements in lithology identification,surface parameter measurements,logistic tracking and autonomous navigation.Laser scanning has the potential to provide real-time solutions but the lack of infrastructure in underground mines for data transfer,geodetic networking and processing capacity remain limiting factors.Nevertheless,laser scanners are becoming an integral part of mine automation thanks to their affordability,accuracy and mobility,which should support their widespread usage in years to come.展开更多
Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data ...Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data products.One consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)receivers.This research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade performance.Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known.To begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user community.In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability.The RTK positioning data from the drone were then used for direct georeferencing,and its results were evaluated.Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 cm.Evaluated against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm.Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.展开更多
Unmanned aerial vehicles(UAVs)can be used to monitor traffic in a variety of settings,including security,traffic surveillance,and traffic control.Numerous academics have been drawn to this topic because of the challen...Unmanned aerial vehicles(UAVs)can be used to monitor traffic in a variety of settings,including security,traffic surveillance,and traffic control.Numerous academics have been drawn to this topic because of the challenges and the large variety of applications.This paper proposes a new and efficient vehicle detection and tracking system that is based on road extraction and identifying objects on it.It is inspired by existing detection systems that comprise stationary data collectors such as induction loops and stationary cameras that have a limited field of view and are not mobile.The goal of this study is to develop a method that first extracts the region of interest(ROI),then finds and tracks the items of interest.The suggested system is divided into six stages.The photos from the obtained dataset are appropriately georeferenced to their actual locations in the first phase,after which they are all co-registered.The ROI,or road and its objects,are retrieved using the GrabCut method in the second phase.The third phase entails data preparation.The segmented images’noise is eliminated using Gaussian blur,after which the images are changed to grayscale and forwarded to the following stage for additional morphological procedures.The YOLOv3 algorithm is used in the fourth step to find any automobiles in the photos.Following that,the Kalman filter and centroid tracking are used to perform the tracking of the detected cars.The Lucas-Kanade method is then used to perform the trajectory analysis on the vehicles.The suggested model is put to the test and assessed using the Vehicle Aerial Imaging from Drone(VAID)dataset.For detection and tracking,the model was able to attain accuracy levels of 96.7%and 91.6%,respectively.展开更多
Most surveying works for mapping or GIS applications are performed with total station. Due to the remote nature of many of the sites surveyed, the surveys are often done in unprojected, local, assumed coordinate syste...Most surveying works for mapping or GIS applications are performed with total station. Due to the remote nature of many of the sites surveyed, the surveys are often done in unprojected, local, assumed coordinate systems. However, without the survey data projected in real world coordinates, the range of possible analyses is limited and the value of existing imagery, elevation models, and hydrologic layers cannot be exploited. This requires a transformation from the local assumed to the real world coordinate systems. There are various built-in and add-in tools to perform transformations through GIS programs. This paper studies the effect of using Georeferencing tool, Spatial Adjustment tool (Affine and similarity) and CHaMP tool on the precision and relative accuracy of total station survey. This transformation requires real-world coordinates of at least two control points, which can be collected from different sources. This paper also studies the effect of using geodetic GPS, hand-held GPS, Google Earth (GE) and Bing Basemaps as sources for control points on the precision and relative accuracy of total station survey. These effects have been tested by using 111 points covered area of 60,000 m2and the results have shown that the CHaMP tool is the best for preserving the relative accuracy of the transformed points. The Georeferencing and spatial adjustment (similarity) tools give the same results and their accuracy are between 1/1000 and 1/300 depending on the source of control points. The results have also shown that the cornerstone to preserve the precision and relative accuracy of the transformed coordinates is the relative position of the control points despite their source.展开更多
Perhaps no region on earth presents such a confusing array of place names as does the area made up of the former provinces of Kham and Amdo in historic Tibet (Xizang). Within these areas, cities, towns, villages, moun...Perhaps no region on earth presents such a confusing array of place names as does the area made up of the former provinces of Kham and Amdo in historic Tibet (Xizang). Within these areas, cities, towns, villages, mountains, lakes and other geographic features have at least two names applied to them, one Tibetan, the other Chinese. Overlying this indigenous nomenclature are the names applied by outsiders, mostly Europeans, each of whom used their native language to transliterate the names they heard or read from Tibetan or Chinese script, and names in the languages of other ethnic minorities who live within the area. Adding to the confusion are the conflicting “standards” for transliterating Tibetan and Chinese names. To resolve the inconsistencies and uncertainties of place names in this region, a multilingual gazetteer and thesaurus was prepared. The gazetteer-thesaurus was compiled to be used as a tool for correlating the often radically different names assigned to a single place or feature and to provide the geographic coordinates for each. The impetus for this project was the need to assign geographic coordinates to plant specimens collected in the area since the latter part of the 19th century up until the advent and widespread use of Global Positioning System (GPS) receivers in the 1990s. Georeferencing specimens is necessary for plotting the historical distribution of species and for more completely understanding the information contained on specimen labels. Knowing the distribution of plants is important for answering phylogenetic questions, determining local and widespread biogeographical patterns, identifying areas of unusually high diversity or endemism, and determining areas in need of special protection. The value of such a gazetteer, however, extends well beyond the field of botany. It is intended to be of use to anyone with a desire to know the nomenclatural history of places in the area and for pinpointing with a fair degree of accuracy the location of each of those places.展开更多
This paper explores potential of Remote Sensing and Geospatial Information Systems as viable tools for data collection, processing, transformation and adjustment of cadastral data discrepancies often noted by geospati...This paper explores potential of Remote Sensing and Geospatial Information Systems as viable tools for data collection, processing, transformation and adjustment of cadastral data discrepancies often noted by geospatial practitioners during rasterization and vectorization of land related data. Necessary datasets were collected employing main approach/procedure of scanning, georeferencing, digitization, transformation and analysis in that order, to amalgamate and harmonize all datasets into one common projection and coordinate system （Universal Transverse Mercator （UTM） on Arc-Datum 1960）. Discrepancies in derived areas against recorded values in land registries were noted, smaller parcels exhibited smaller discrepancies and vice versa. Discrepancies were found to be directly proportional to the parcel areas/sizes although large parcels （〉 1000 m2） exhibited abnormally high discrepancies. This procedure yielded systematic discrepancies that could be minimized by use of a fifth order polynomial. Resultant residuals were found to be tolerably low and could be ignored for small parcels （〈 1000 m2）. Final outputs included automated GIS geodatabase cadastre, containing cadastral attributes harmonized to one projection and coordinate system that can be overlaid to other datasets from engineering design and construction works, geological and geotechnical investigation surveys, etc. tied to Remote Sensing data without the requirement of further transformations.展开更多
This paper describes the experience carried out with the aim to provide a technical and geo-referenced contribution to a project, submitted to the Common of Peschiera Borromeo in the Province of Milan in Lombardy. The...This paper describes the experience carried out with the aim to provide a technical and geo-referenced contribution to a project, submitted to the Common of Peschiera Borromeo in the Province of Milan in Lombardy. The promoter is a group of local associations;the aim is the valorisation and fruition of a green area, named Carengione Oasis. At first a GIS pre-analysis of the area has been performed to achieve a thorough knowledge of the area object of study. Then, a handheld GSP navigator has been employed to collect the data to be processed in a GIS software. This device choice has pros (a fast and very easy survey has been carried out) and cons (the acquired data have a precision of 3 to 5 meters). These data have been processed with the aid of the GIS software ArcMap release 10.4.1 by Esri. Also some free aerial images have been employed to edit features inaccessible on site. The achieved results are some thematic, metric and georeferenced maps and also a 3D virtual tour for a realistic visit of this area. They fulfil the project requirements. Anyway, due to their low precision, they have not been uploaded to enrich the official Lombardy cartography (DBTR);for this reason, part of them has been donated to the free data interchange OpenStreetMap. This work could be considered as a first step for future more precise surveys which would allow adding the acquired results to the DBTR;it has also been planned to create a story map describing the experience illustrated in this paper.展开更多
A device was designed to test the dynamic accuracy of Global Positioning System(GPS)receivers used in agricultural aircraft and other aerial vehicles.The system works by directing a sun-reflected light beam from the g...A device was designed to test the dynamic accuracy of Global Positioning System(GPS)receivers used in agricultural aircraft and other aerial vehicles.The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors.A photo detector points downward from the aircraft to detect the light beam,and photo detection circuitry triggers an event in the guidance system data file at the aircraft’s location corresponding to the precisely georeferenced position on the ground.Construction details are presented on the mirror-based light reflection system and photo-electronic circuitry designed to trigger an event in the guidance system’s log file.An example application evaluated the horizontal accuracy of a stand-alone GPS receiver by matching dynamic data with data from the aircraft’s guidance system.Results indicated a 2.16 s lead in position registered by the stand-alone receiver over that registered by the aircraft’s guidance system GPS receiver,which had been previously evaluated to be within 0.13 s of Real-Time Kinematic(RTK)-referenced time and position.展开更多
文摘This paper implements and evaluates experimentally a procedure for automatically georeferencing images acquired by unmanned aerial vehicles(UAV s) in the sense that ground control points(GCP) are not necessary. Since the camera model is necessary for georeferencing, this paper also proposes a completely automatic procedure for collecting corner pixels in the model plane image to solve the camera calibration problem, i.e., to estimate the camera and the lens distortion parameters. The performance of the complete georeferencing system is evaluated with real flight data obtained by a typical UAV.
文摘Addresses are important data for urban applications. About 80% of the information local authorities use have a geographic component that is generally related to addresses. Addressing systems efficiency depend on the quality of addresses locators. There are several methods to collect data. Surveys from the field are essential: GPS and pre-printed maps can be used to achieve this goal. GPS surveys from the field may be a solution, but it remains practical only for limited areas. To insure an accepted accuracy, GPS methods need special considerations that are time and money consuming. For Casablanca’s addressing locators, an alternative approach was adopted to collect 400 000 points. It took two months, 200 operators and 3500 printed maps to cover a study area of1,226 km2. This paper is to develop an optimized approach based on automated procedure for reintegrating printed maps in a geographic information system (GIS). It saves georeferencing time from 5min to just seconds per document. It insures, more importantly, an accuracy that is between20 cmto1 mfor scales that are between 1/500 and 1/2500. It ensures maps’ integration, independently of base map and coordinates system by introducing the notion of Georeferencing Code (GC).
文摘The usage of georeferencing as a search tool has suffered a massification after the diffusion of technologies developed by Google and Microsoft. In this context, problems related to the location of properties situated on highways are becoming quite usual in Brazil, because properties registration in highway is permitted in the country and this invalidates the dynamics of the georeferencing process. Therefore, a growing number of geotechnology users which desire to localize properties on highways, find inaccurate or amiss geographical information. This research focus is to present an enumeration method for highway properties and, consequently, the possibility of a precise georeferencing. The presented method contributes to turning possible the precision of this georeferencing process and it will also be relevant for geotechnology diffusion considering its integration to geographic information systems which include geocoding tools.
文摘The port of Callao is important for its varied historical and archaeological heritage,which includes several military buildings that were the main actors and witnesses of the colonial era of Peru(from the 16th century to the country’s independence from Spain early in the 19th century).Despite the studies that have been carried out on the basis of documents and some eventual archaeological excavations,the port’s main monument,namely,the Real Felipe Fortress,continues to hide very important information that could be used to understand the role that the fortress played in numerous historical events throughout the centuries.The main contribution of this study is the use of photogrammetry software and a Geographic Information System(GIS)to examine the Real Felipe Fortress.In this way,the nature of the atypical construction within the fortress is determined.As a result,it is possible to accurately establish the location of the defensive wall that surrounded the ancient city of Callao,as well as its first churches,whose records were lost after being destroyed by the 1746 earthquake and tsunami in Lima,the worst cataclysm registered in the history of Peru and South America.As a result,this study demonstrates that technology can be successfully used to establish and validate with great precision the existence of the location of churches that have been built in the port of Callao since the founding of Lima in the 16th century.Such identification allows architects,engineers and students who are interested in the history of monuments to discover hidden structures and buildings and carry out the necessary restoration and archaeological works,with the aim of recovering the history of the colonial architecture of Callao and other similar cities and ports worldwide.
基金the Australian Coal Industry’s Research Program(ACARP)(Project No.C27057).
文摘Laser scanning can provide timely assessments of mine sites despite adverse challenges in the operational environment.Although there are several published articles on laser scanning,there is a need to review them in the context of underground mining applications.To this end,a holistic review of laser scanning is presented including progress in 3D scanning systems,data capture/processing techniques and primary applications in underground mines.Laser scanning technology has advanced significantly in terms of mobility and mapping,but there are constraints in coherent and consistent data collection at certain mines due to feature deficiency,dynamics,and environmental influences such as dust and water.Studies suggest that laser scanning has matured over the years for change detection,clearance measurements and structure mapping applications.However,there is scope for improvements in lithology identification,surface parameter measurements,logistic tracking and autonomous navigation.Laser scanning has the potential to provide real-time solutions but the lack of infrastructure in underground mines for data transfer,geodetic networking and processing capacity remain limiting factors.Nevertheless,laser scanners are becoming an integral part of mine automation thanks to their affordability,accuracy and mobility,which should support their widespread usage in years to come.
文摘Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data products.One consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)receivers.This research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade performance.Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known.To begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user community.In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability.The RTK positioning data from the drone were then used for direct georeferencing,and its results were evaluated.Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 cm.Evaluated against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm.Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.
基金supported by the MSIT(Ministry of Science and ICT),Korea,under the ICAN(ICT Challenge and Advanced Network of HRD)program(IITP-2023-RS-2022-00156326)supervised by the IITP(Institute of Information&Communications Technology Planning&Evaluation).
文摘Unmanned aerial vehicles(UAVs)can be used to monitor traffic in a variety of settings,including security,traffic surveillance,and traffic control.Numerous academics have been drawn to this topic because of the challenges and the large variety of applications.This paper proposes a new and efficient vehicle detection and tracking system that is based on road extraction and identifying objects on it.It is inspired by existing detection systems that comprise stationary data collectors such as induction loops and stationary cameras that have a limited field of view and are not mobile.The goal of this study is to develop a method that first extracts the region of interest(ROI),then finds and tracks the items of interest.The suggested system is divided into six stages.The photos from the obtained dataset are appropriately georeferenced to their actual locations in the first phase,after which they are all co-registered.The ROI,or road and its objects,are retrieved using the GrabCut method in the second phase.The third phase entails data preparation.The segmented images’noise is eliminated using Gaussian blur,after which the images are changed to grayscale and forwarded to the following stage for additional morphological procedures.The YOLOv3 algorithm is used in the fourth step to find any automobiles in the photos.Following that,the Kalman filter and centroid tracking are used to perform the tracking of the detected cars.The Lucas-Kanade method is then used to perform the trajectory analysis on the vehicles.The suggested model is put to the test and assessed using the Vehicle Aerial Imaging from Drone(VAID)dataset.For detection and tracking,the model was able to attain accuracy levels of 96.7%and 91.6%,respectively.
文摘Most surveying works for mapping or GIS applications are performed with total station. Due to the remote nature of many of the sites surveyed, the surveys are often done in unprojected, local, assumed coordinate systems. However, without the survey data projected in real world coordinates, the range of possible analyses is limited and the value of existing imagery, elevation models, and hydrologic layers cannot be exploited. This requires a transformation from the local assumed to the real world coordinate systems. There are various built-in and add-in tools to perform transformations through GIS programs. This paper studies the effect of using Georeferencing tool, Spatial Adjustment tool (Affine and similarity) and CHaMP tool on the precision and relative accuracy of total station survey. This transformation requires real-world coordinates of at least two control points, which can be collected from different sources. This paper also studies the effect of using geodetic GPS, hand-held GPS, Google Earth (GE) and Bing Basemaps as sources for control points on the precision and relative accuracy of total station survey. These effects have been tested by using 111 points covered area of 60,000 m2and the results have shown that the CHaMP tool is the best for preserving the relative accuracy of the transformed points. The Georeferencing and spatial adjustment (similarity) tools give the same results and their accuracy are between 1/1000 and 1/300 depending on the source of control points. The results have also shown that the cornerstone to preserve the precision and relative accuracy of the transformed coordinates is the relative position of the control points despite their source.
基金Supported by the U. S. National Science Foundation, Grant No. DEB-0321846, and the National Natural Science Foundation of China, Grant No. 40332021.
文摘Perhaps no region on earth presents such a confusing array of place names as does the area made up of the former provinces of Kham and Amdo in historic Tibet (Xizang). Within these areas, cities, towns, villages, mountains, lakes and other geographic features have at least two names applied to them, one Tibetan, the other Chinese. Overlying this indigenous nomenclature are the names applied by outsiders, mostly Europeans, each of whom used their native language to transliterate the names they heard or read from Tibetan or Chinese script, and names in the languages of other ethnic minorities who live within the area. Adding to the confusion are the conflicting “standards” for transliterating Tibetan and Chinese names. To resolve the inconsistencies and uncertainties of place names in this region, a multilingual gazetteer and thesaurus was prepared. The gazetteer-thesaurus was compiled to be used as a tool for correlating the often radically different names assigned to a single place or feature and to provide the geographic coordinates for each. The impetus for this project was the need to assign geographic coordinates to plant specimens collected in the area since the latter part of the 19th century up until the advent and widespread use of Global Positioning System (GPS) receivers in the 1990s. Georeferencing specimens is necessary for plotting the historical distribution of species and for more completely understanding the information contained on specimen labels. Knowing the distribution of plants is important for answering phylogenetic questions, determining local and widespread biogeographical patterns, identifying areas of unusually high diversity or endemism, and determining areas in need of special protection. The value of such a gazetteer, however, extends well beyond the field of botany. It is intended to be of use to anyone with a desire to know the nomenclatural history of places in the area and for pinpointing with a fair degree of accuracy the location of each of those places.
文摘This paper explores potential of Remote Sensing and Geospatial Information Systems as viable tools for data collection, processing, transformation and adjustment of cadastral data discrepancies often noted by geospatial practitioners during rasterization and vectorization of land related data. Necessary datasets were collected employing main approach/procedure of scanning, georeferencing, digitization, transformation and analysis in that order, to amalgamate and harmonize all datasets into one common projection and coordinate system （Universal Transverse Mercator （UTM） on Arc-Datum 1960）. Discrepancies in derived areas against recorded values in land registries were noted, smaller parcels exhibited smaller discrepancies and vice versa. Discrepancies were found to be directly proportional to the parcel areas/sizes although large parcels （〉 1000 m2） exhibited abnormally high discrepancies. This procedure yielded systematic discrepancies that could be minimized by use of a fifth order polynomial. Resultant residuals were found to be tolerably low and could be ignored for small parcels （〈 1000 m2）. Final outputs included automated GIS geodatabase cadastre, containing cadastral attributes harmonized to one projection and coordinate system that can be overlaid to other datasets from engineering design and construction works, geological and geotechnical investigation surveys, etc. tied to Remote Sensing data without the requirement of further transformations.
文摘This paper describes the experience carried out with the aim to provide a technical and geo-referenced contribution to a project, submitted to the Common of Peschiera Borromeo in the Province of Milan in Lombardy. The promoter is a group of local associations;the aim is the valorisation and fruition of a green area, named Carengione Oasis. At first a GIS pre-analysis of the area has been performed to achieve a thorough knowledge of the area object of study. Then, a handheld GSP navigator has been employed to collect the data to be processed in a GIS software. This device choice has pros (a fast and very easy survey has been carried out) and cons (the acquired data have a precision of 3 to 5 meters). These data have been processed with the aid of the GIS software ArcMap release 10.4.1 by Esri. Also some free aerial images have been employed to edit features inaccessible on site. The achieved results are some thematic, metric and georeferenced maps and also a 3D virtual tour for a realistic visit of this area. They fulfil the project requirements. Anyway, due to their low precision, they have not been uploaded to enrich the official Lombardy cartography (DBTR);for this reason, part of them has been donated to the free data interchange OpenStreetMap. This work could be considered as a first step for future more precise surveys which would allow adding the acquired results to the DBTR;it has also been planned to create a story map describing the experience illustrated in this paper.
文摘A device was designed to test the dynamic accuracy of Global Positioning System(GPS)receivers used in agricultural aircraft and other aerial vehicles.The system works by directing a sun-reflected light beam from the ground to the aircraft using mirrors.A photo detector points downward from the aircraft to detect the light beam,and photo detection circuitry triggers an event in the guidance system data file at the aircraft’s location corresponding to the precisely georeferenced position on the ground.Construction details are presented on the mirror-based light reflection system and photo-electronic circuitry designed to trigger an event in the guidance system’s log file.An example application evaluated the horizontal accuracy of a stand-alone GPS receiver by matching dynamic data with data from the aircraft’s guidance system.Results indicated a 2.16 s lead in position registered by the stand-alone receiver over that registered by the aircraft’s guidance system GPS receiver,which had been previously evaluated to be within 0.13 s of Real-Time Kinematic(RTK)-referenced time and position.
