Digital Topographic Mapping in Urban Obstructed Environment Based on Multi-GNSS Network RTK Technology

With the development of modern small satellite technology, it is potential and significant to use the new technology for the earth observation. The stereo mapping micro-satellite—“Experiment Satellite 1”, designed and built by Harbin Institute of Technology, is taken as an example for discussion of the relevant technologies and corresponding principle of the satellite payload and its ground application system. The gr ound application system recei ves the stereo photographs data from the “Experiment Satellite 1” and then produces surveying products such as digital elevation map, digital orthoimage and digital topographic map, etc. “Experiment Satellite 1” is the first satellite where three-line-array CCD camera is used triumphantly in world for stereo mapping. It will have profound influence on the earth observation technique. Keywords: Stereo mapping micro-satellite, Payload, Photogrammet ry, Ground application system, Ground station, Data processing center, Accessorial photogrammetry data, Digital orth oimage, Digital topographic map.

In recent years, there has been a rapid advancement in the use of unmanned aerial vehicles (UAVs) in various aspects of life, especially in the area of automated data collection. These advancements have brought about numerous possibilities. The article describes the use of an unmanned aerial vehicle, specifically the PHANTOM 4 pro, to gather remote sensing data and create digital topographic plans at a scale of 1:2000 in Phu Tho province's Thanh Son district. A method was suggested for improving the current systems for obtaining remote sensing data for cartography using UAVs. The ease of controlling the UAVs and the quality and timeliness of the data they transmit to control points confirm the value of using them to create topographic maps. In addition to UAVs, fieldwork also involves the use of the GNSS brand CHCNAV I50. The high precision GNSS system enables the camera's 3D position to be detected within a few centimeters at the time of each capture. A digital topographic map was compiled of Thanh Son district, covering 165 hectares, and processed using software such as Agisoft and Global Mapper. The digital topographic map that was produced satisfies the documentation requirements of government organizations. The maximum error in height is 4.7 cm, the error of coordinates north and east are 1.8 cm and 1.4 cm respectively. This was achieved by using 590 raster images, which had a resolution of 2.3 cm and a size of 5472x3648 pixels. Based on the findings, the map's accuracy is within an acceptable range of less than 2 cm, which is suitable for a map scale of 1:2000.

Abstract. This research examines the problem of automation of quality control of digital topographic maps at the scale 1:50 000 of the Main State Topographic Map in Ukraine for the creation and maintaining the seamless topographic database for national needs, which is located on the Geoportal to ensure the development of the National Spatial Data Infrastructure (NSDI) in Ukraine. The authors determined stages of quality control of digital topographic maps at the scale of 1:50 000 for the automation one according to ISO 19157:2013 Geographic Information – Data quality. The realized automated quality control of geodatabases of updated digital topographic maps at a scale of 1:50 000 provides high speed and quality of validation: validation of quality data elements; validation of quality metadata; validation of positional accuracy. The software package “Validate” was developed for automation quality control geodatabases of digital topographic maps at the scale of 1:50 000 using the Python programming language to verify logical consistency, compliance with the rules of topological relationships between features on the map, availability and content of metadata. The “Validate” can be used for automation quality control geodatabase for any map scale, performing setting according to the requirements of the geospatial models.

Sustainable High-rises

Today Global Navigation Satellite Systems (GNSS) are widely used for determining position. Within the city environment, however, in which there are many tall buildings, GNSS signals are frequently interrupted, making it difficult for users to obtain information on their exact position. This paper analyzed the availability and positioning performance of a GPS augmented system within the Seoul urban area using the Japanese QZSS (Quasi-Zenith Satellite System) and a geostationary satellite. A 3-dimensional reproduction of Seoul that was based on the 3D GIS (Geographic Information System) Digital Map and a satellite tracking algorithm using Ray-Triangle Intersection algorithm were discussed. A satellite tracking algorithm was verified through filed testing and the QZSS orbit simulator was realized using Keplerian parameter. DOP (Dilution of Precision) and availability in the urban area of Seoul were analyzed using a GPS/QZSS/geostationary satellite separately and simultaneously.

With the advent of the Global Position System (GPS), we now have the ability to determine absolute position anywhere on the globe. Although GPS system work well in open environments with no overhead obstructions, they re subject to large unavoidable errors when the reception from some of the satellites is blocked. This occurs frequently in urban environments, such as downtown New York City. GPS systems require at least four satellites visible to maintain a good position 'fix', and tall buildings and tunnels often block several, if not all, of the satellites. Additionally, due to selective availability, where small amounts of error are intentionally introduced, GPS errors can typically range up to 100 ft or more. This paper proposes several methods for improving the position estimation capabilities of a system by incorporating other sensor and data technologies, including Kalman filtered inertial navigation system, rule- based and fuzzy-based senors fusion techniques, and a unique map-matching algorithm.

Buildings represent one of the most significant sources of negative impacts to the natural ecosystems on which Qatar's inhabitants health and environmental quality depend. The market has identified Qatar as one of the busiest construction areas in the world (Ibrahim 2011), While rapid economic development, population growth, and construction boom are positive indicators of growth, they may also present issues related to the negative impact on the socio-environmental components of cities. Such is the case of the Gulf Cooperation Council (GCC) countries where increasing economic prosperity has led to a surge in tall building construction and a sense of competition to erect the tallest skyscrapers in the world (Mahgoub and Abarra 2012).While tall buildings are a source of national pride and cultural identity enabled by economic prosperity, they pose several challenges to integrate with the urban fabric of the city while also having a tremendous environmental impact. Tall buildings are especially massive consumers of energy (Ali and Armstrong 2008). They are the dominant elements in urban architecture due to their scale and purpose, and should be the focus of sustainable design. With large number of towers constructed and to be constructed in Al Dafna and West Bay areas of Doha, these buildings affect different aspects of the built and urban environment, i.e., city image, traffic, urban spaces and physical conform. Therefore, more architectural design strategies have to be planned well ahead in order to tackle the issues of sustainability and adaptability to climate change and to foster sustainable built environment in the state of Qatar.With Qatar slated to host a ‘zero carbon’ World Cup in 2022, Qatar Green Building Council (QGBC) has set up a group to foster green infrastructure as a national resource. Qatar is utilizing Leadership in Energy and Environmental Design (LEED) and the Global/Qatar Sustainability Assessment System (GSAS/QSAS) to this end. Furthermore, shortages in raw materials between 2013 and 2017 are expected to challenge the construction sector, as the period is expected to be the peak for the sector. Therefore, the sector will have to bridge the gap during this period by mutual agreements with the companies in Saudi Arabia and the UAE (QCB 2012).The objectives of this paper are as follows: 1- to Identify sustainability metrics for tall buildings with focus on construction materials and methods used in Qatar; 2- Explore existing literature and identify analogies in optimization consistent with design variables; 3- to examine sustainability of construction materials used in Qatar by utilizing software which is based on currently available databases to perform life cycle assessment.To meet the objectivess described above, the currently available software platforms to perform life cycle analysis of building materials were explored. A commercial software, SimaPro, which utilizes the environmental impact database Ecoinvent, was chosen for its flexibility in defining custom mix designs for concrete, as well as database information on steel and many other building materials. With SimaPro, a sustainability model for concrete and steel was developed which reflects the environmental implications of manufacture of materials in Qatar as appropriate. Quantitative results from the model for the sustainability of constituents of building materials were extracted, to form the basis of sustainability metrics in the forthcoming tall building topology optimization protocol.Furthermore, Blanco-Carrasco et al (2010) outline reduced use of Portland cement, increased use of alternate cementitious materials, and reduced water use to improve the sustainability of the concrete industry in Qatar. Using structural models and the SimaPro model, ultra-high performance concrete was explored as a potential solution for all these problems, to be applied in the gravity/lateral structural components of Qatar tall buildings. In addition to identifying a novel material which fits well with the current tall building designs of the region, the process of examining the structural and environmental improvements from using ultra-high performance concrete has resulted in the formation of a procedure to compare multiple materials used in Qatar.This paper is a result of a funded research project by QNRF, entitled “Multi–Objective Tall Building Topologies – Optimizing for Structural Performance, Economy, and Sustainability” and a jointly collaboration between researchers from Qatar University, Virginia Tech, Johns Hopkins University, Optim Design Inc, and MZ & Partners.“This research/publication was made possible by a National Priority Research Program NPRP award [NPRP- 7 - 1518 - 2 – 549] from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the author(s).”

Remote sensing and GIS technologies are very useful for mapping LULC patterns and detailing the dynamics of a certain area. The utilization of these technologies has been applied to Bodri watershed in Central Java, Indonesia. The aims of this study are to map and detect LULC changes in Bodri watershed over the last two decades (1991-2001 and 2001-2009). Three data sets of Landsat image acquired on June 28, 1991; July 1, 2001 and June 21, 2009 were used for this analysis. Image classification for mapping LULC was performed by supervised classification through the maximum likelihood method. All of the visible and infrared bands (bands 1-5 and 7) were used for the analysis. LULC change processes were then detected through post classification comparison method. Analyzing LULC changes associated to its slope and elevation were performed by overlaying the classified image with slope and elevation maps which had been extracted from digital topographic map (1:25,000). Six LULC categories were classified as forest, tree plantation, dry farming field, paddy field, settlement and water. The results show that in the period of 1991-2001 there were increases in settlement (56.22%), dry farming field (41.77%) and water (32.41%), and decrease in forest (-31.85%), tree plantation (-15.19%) and paddy field (-12.23%). While, between 2001 and 2009 increase occurred in water (34.17%), tree plantation (12.63%) and settlement (7.47%), and decrease in paddy field (26.01%), forest (-12.33%) and dry farming field (-1.14%). The changes predominantly took place in the gentle slope (0-8%) and the low elevation (0-500 m) areas. These results show that urbanization and agricultural activities have occurred in these areas. The low land and gentle slope were more widely affected by and vulnerable to human and agriculture caused LULC changes than highland and steep slope areas.

GIS based optimal impervious surface map generation using various spatial data for urban nonpoint source management

This study aims to assess habitat feature on the large-scale spawning ground of the Boreal Digging Frog Kaloula borealis in Daemyung retarding basin of Daegu, and to analyze the relationships between species abundance and meteorological factors for each habitat. Fifty-seven(57) pitfalls were installed to collect species abundance of 4 survey regions, and high-resolution satellite image, soil sampling equipment, digital topographic map, and GPS were used to develop habitat features such as terrain, soil, vegetation, human disturbance. The analysis shows that the frog is most abundant in sloped region with densely herbaceous cover in southern part of the retarding basin. In the breeding season, lowland regions, where Phragmites communis and P. japonica dominant wetlands and temporary ponds distributed, are heavily concentrated by the species for spawning and foraging. Located in between legally protected Dalsung wetands and lowland regions of the retarding basin, riverine natural levee is ecologically important area as core habitat for Kaloula borealis, and high number of individuals were detected both breeding and non-breeding seasons. Temperate- and pressure-related meteorological elements are selected as statistically significant variables in species abundance of non-breeding season in lowland and highland regions. However, in sloped regions, only a few variables are statistically significant during non-breeding season. Moreover, breeding activities in sloped regions are statistically significant with minimum temperature, grass minimum temperature, dew point temperature, and vapor pressure. Significant meteorological factors with habitat features are effectively applied to establish species conservation strategy of the retarding basin and to construct for avoiding massive road-kills on neighboring roads of the study sites, particularly post-breeding movements from spawning to burrowing areas.

Facing-slope measurement from topographic maps was the traditional method used to divide sub-compartment for forest management division. However, the sub-compartment, which usually covers a large area and contains multiple forest types, can not be divided accurately and intuitively. Therefore it is not easy to operate in forestry management practice. An improved forest management planning method based on 3S technology with considering the reality of forest management was proposed in this paper. Firstly, forest function regions were distinguished based on digital topographic map. Secondly, the stands were divided in every sub-compartment based on high spatial resolution images by visual interpretation method in ArcGIS software. Thirdly, many neighboring sub-compartments with same geographical characteristics were combined into one operating area which was convenient for operating management forest. Then stands with the same management mode in one operating area were merged. Finally, compiling computer program to implement the aim of inputting some attribute information to generate other attribute information automatically. The approach put forward in this paper not only allows the forest management sophisticated, targeted but also easy to practice and implement.

A flood analysis of the Hyoja drainage basin (Gwanghwamun area) in Seoul was conducted using the XP-SWMM model, which includes 315 pipeline datas and 293 subbasins. The model was created by considering topographical factors (e.g., pipeline slope and buildings). curve number (CN) values were determined for each subbasin based on land use and detailed soil maps for estimating infiltration. Additionally, a digital terrain model (DTM) was generated using a 1:5,000 digital topographical map and survey data.In the XP-SWMM model, the evaluation of ponding varies depending on the ponding conditions (e.g., Ponding Allowed(PA), Link Spill Crest to 2D(2D), None Poning(NP)), leading to considerable differences in the calculation of hydraulic heads at the nodes. The Hyoja drainage basin, the focus of this study, features a steep slope in the upstream area and hilly terrain in the downstream, indicating potential limitations in accurately modeling flood volume.To overcome the limitations of the XP-SWMM model, the surface slope and lowlands were incorporated when establishing node conditions. Areas with a slope of less than 5% were assigned the “2D” option, whereas areas with a slope greater than 5% were assigned the “NP” condition. In addition, supplementary modeling was conducted by combining certain subbasins to assess the impact of runoff from upstream areas on downstream flooding.The flood volume analysis based on the ponding conditions under 95 mm/hr rainfall revealed that the “NP” condition tended to underestimate flood volume, while the “2D” condition tended to overestimate it by assuming ponding was present even in sloped areas. As a result, the “2D” condition was applied to basins with a surface slope of 5% or less, while the “NP” condition was applied to areas that were not lowlands. Lowlands were designated as areas with an elevation below 40.0 m, accounting for approximately 20% of the total area.When comparing the flood volume before and after merging the subbasins, the flood volume in upstream areas with a slope of 5% or more decreased, whereas the volume in the downstream Gwanghwamun area increased. This situation was attributed to runoff from the upstream basin, which added to the increase in the downstream flood volume.The study findings showed that by setting node ponding conditions considering basin slope and lowland conditions, simulating flooding events that closely resemble actual occurrences is possible. Thus, limitations of the XP-SWMM model can be overcome. Furthermore, merging subbasins has proven to be an effective approach for analyzing the interactions between upstream and downstream regions and assessing the impacts of critical flood zones. Technical decisions should reflect consideration for characteristics of the basin and topographical factors when designing a modelAcknowledgementsThis work was supported by Korea Planning & Evaluation Institute of Industrial Technology funded by the Ministry of the Interior and Safety (MOIS, Korea). [Development and Application of Advanced Technologies for Urban Runoff Storage Capability to Reduce the Urban Flood Damage / RS-2024-00415937]  

Path‐finding problems have attracted widespread research interest in GIS‐T. Previous research has largely been conducted on developing shortest path algorithms in GIS. The conventional approach is to adopt the arc‐node network model, which allows only users with expert knowledge to generate measurements such as optimal paths from a map. However, the generation and maintenance of a centreline network are difficult and tedious because these are not natural on‐ground features but imaginary lines on a map. To remedy the situation, a revolutionary approach has been suggested that path‐finding method is independent of extra arc‐node data creations by end‐users. By using the cell‐decomposition method borrowed from motion planning of a robot, general map users may obtain an optimal path by just identifying familiarized symbols/outlines from a digital topographic map without resorting to generating an extra set of centrelines.

The policy for the recent maintenance of natural disaster is operating the disaster system from preliminary expectation, forecasting and respond, and for this it is necessary to raise the efficient work related to disaster through the scientific analysis and quick investigation of past disaster history. This research used spatial information of disaster attribute, digital image, digital topographic map, cadastral map and geological map for the efficient maintenance of disaster through scientific analysis and quick investigation to construct the disaster information system and evaluated the application of disaster management system. Disaster information system used the spatial information and disaster attribute information to make an efficient performance of functions necessary for disaster management such as disaster zone management, geological analysis and automatized calculation of damage area, and made the efficient disaster management through the extraction of cadastral information and damage area more than certain scale by damage area. In the future, this system can be used for the objective and quick recovery plan of disaster damage investigation and disaster related decision making.KeywordsDisaster Information SystemDisaster ManagementOpen SourceDisaster SystemDamage Investigation

Time series of water table depths (H t ) are predicted in space using a regionalised autoregressive exogenous variable (RARX) model with precipitation surplus (#E5 /E5# t ) as input variable. Because of their physical basis, RARX model parameters can be guessed from auxiliary information such as a digital elevation model (DEM), digital topographic maps and digitally stored soil profile descriptions. Three different approaches to regionalising RARX parameters are used. In the `direct' method (DM) #E5 /E5# t is transformed into H t using the guessed RARX parameters. In the `indirect' method (IM) the predictions from DM are corrected for observed systematic errors. In the Kalman filter approach the parameters of regionalisation functions for the RARX model parameters are optimised using observations on H t . These regionalisation functions describe the dependence on spatial co-ordinates of the RARX parameters. External drift kriging and simple kriging with varying means are applied as regionalisation functions, using guessed RARX model parameters or DEM data as secondary variables. Predictions of H t at given days, as well as estimates of expected water table depths are made for a study area of 1375 ha. The performance of the three approaches is tested by cross-validation using observed values of H t in 27 wells which are positioned following a stratified random sampling design. IM performs significantly better with respect to systematic errors than the alternative methods in estimating expected water table depths. The Kalman filter methods perform better than both DM and IM in predicting the temporal variation of H t , as is indicated by lower random errors. Particularly the Kalman filter method that uses DEM data as an external drift outperforms the alternative methods with respect to the prediction of the temporal variation of the water table depth.