A Subdivision Method to Unify the Existing Latitude and Longitude Grids

Cheng, Chengqi; Tong, Xiaochong; Chen, Bin; Zhai, Weixin

doi:10.3390/ijgi5090161

Cited by 44 publications

(17 citation statements)

References 12 publications

(16 reference statements)

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“…According to the administrative division, the internal area is divided into several grid units according to a certain division scale, forming different levels of a multi-level grid. The global GeoSOT grid proposed by Cheng et al is very suitable for urban grid management because of its hierarchical nesting, high computational efficiency, and easy conversion of latitude and longitude [24]. We also introduce GeoSOT grid in this model.…”

Section: Grid-based Warning Mapmentioning

confidence: 99%

QRA-Grid: Quantitative Risk Analysis and Grid-based Pre-warning Model for Urban Natural Gas Pipeline

Cheng

2019

IJGI

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With the increasing use and complexity of urban natural gas pipelines, the occurrence of accidents owing to leakage, fire, explosion, etc., has increased. Based on Quantitative Risk Analysis (QRA) models and Geographic Information System (GIS) technology, we put forward a quantitative risk simulation model for urban natural gas pipeline, combining with a multi-level grid-based pre-warning model. We develop a simulation and pre-warning model named QRA-Grid, conducting fire and explosion risk assessment, presenting the risk by using a grid map. Experiments show that by using the proposed method, we can develop a fire and explosion accident pre-warning model for gas pipelines, and effectively predict areas in which accidents will happen. As a result, we can make a focused and forceful policy in areas which have some potential defects in advance, and even carry out urban planning once more, rebuilding it to prevent the risk.

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Section: Grid-based Warning Mapmentioning

confidence: 99%

QRA-Grid: Quantitative Risk Analysis and Grid-based Pre-warning Model for Urban Natural Gas Pipeline

Cheng

2019

IJGI

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“…GeoSOT Subdivision Technique Space subdivision grids, which are discrete, hierarchical, and globally continuous, address both the computer management of continuous spaces and the discretization of aircraft paths and other elements [20].…”

Section: Space Subdivisionmentioning

confidence: 99%

“…To better describe the sizes of the aircraft trajectories and low-altitude obstacles, we base our study on an existing global longitude and latitude subdivision grid of 2 n one-dimension-integer arrays, GeoSOT (geographical coordinate grid subdivision by one-dimension-integer and two to the n-th power) [20]. GeoSOT subdivision essentially extends the longitude and latitude intervals from the eight basic grids up to 512 • (2 9• ), interpolates four levels between 1 • and 2 and another four levels between 1 and 2", and extends the part below 0.5 to 1/2048" to yield a graticule-based subdivision system of {2 8• , 2 7• , 2 6• , 2 5• , 2 4• , 2 3• , 2 2• , 2 1• , 2 0• , 2 5 , 2 4 , 2 3 , 2 2 , 2 1 , 2 0 , 2 5 ", 2 4 ", 2 3 ", 2 2 ", 2 1 ", 2 0 ", 2 −1 ", 2 −2 ", 2 −3 ", 2 −4 ", 2 −5 ", 2 −6 ", 2 −7 ", 2 −8 ", 2 −9 ", 2 −10 ", and expanding segmentation is that the 0-9 layers of grids are all integer degree segmented.…”

Section: Space Subdivisionmentioning

confidence: 99%

A Low-Altitude Flight Conflict Detection Algorithm Based on a Multilevel Grid Spatiotemporal Index

Miao

Cheng

Zhai

et al. 2019

IJGI

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Flight conflict detection is fundamental to flight dispatch, trajectory planning, and flight safety control. An ever-increasing aircraft population and higher speeds, particularly the emergence of hypersonic/supersonic aircrafts, are challenging the timeliness and accuracy of flight conflict detection. Traditional trajectory conflict detection algorithms rely on traversing multivariate equations of every two trajectories, in order to yield the conflict result and involve extensive computation and high algorithmic complexity; these algorithms are often unable to provide the flight conflict solutions required quickly enough. In this paper, we present a novel, low-altitude flight conflict detection algorithm, based on the multi-level grid spatiotemporal index, that transforms the traditional trajectory-traversing multivariate conflict computation into a grid conflict state query of distributed grid databases. Essentially, this is a method of exchanging "storage space" for "computational time". First, we build the spatiotemporal subdivision and encoding model based on the airspace. The model describes the geometries of the trajectories, low-altitude obstacles, or dangerous fields and identifies the grid with grid codes. Next, we design a database table structure of the grid and create a grid database. Finally, we establish a multilevel grid spatiotemporal index, design a query optimization scheme, and examine the flight conflict detection results from the grid database. Experimental verification confirms that the computation efficiency of our algorithm is one order of magnitude higher than those of traditional methods. Our algorithm can perform real-time (dynamic/static) conflict detection on both individual aircraft and aircraft flying in formation with more efficient trajectory planning and airspace utilization.

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“…The GeoSOT-3D grid system proposed for this study is a universal and hierarchical three-dimensional geospatial reference system [40]. By subdividing the Earth through three iterations (initially expanding the Earth (180 • × 360 • ) into 512 • × 512 • grids, then expanding each 1 • into 64 , and finally expanding each 1 into 64"), two-dimensional quadtree subdivisions at the degree, minute, and second levels are obtained.…”

Section: Geosot-3d Grid Systemmentioning

confidence: 99%

Collision Detection for UAVs Based on GeoSOT-3D Grids

Zhai

Tong

Miao

et al. 2019

IJGI

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The increasing number of unmanned aerial vehicles (UAVs) has led to challenges related to solving the collision problem to ensure air traffic safety. The traditional approaches employed for collision detection suffer from two main drawbacks: first, the computational burden of a pairwise calculation increases exponentially with an increasing number of spatial entities; second, existing grid-based approaches are unsuitable for complicated scenarios with a large number of objects moving at high speeds. In the proposed model, we first identified UAVs and other spatial objects with GeoSOT-3D grids. Second, the nonrelational spatial database was initialized with a multitable strategy, and spatiotemporal data were inserted with the GeoSOT-3D grid codes as the primary key. Third, the collision detection procedure was transformed from a pairwise calculation to a multilevel query. Four simulation experiments were conducted to verify the feasibility and efficiency of the proposed collision detection model for UAVs in different environments. The results also indicated that 64 m GeoSOT-3D grids are the most suitable basic grid size, and the reduction in the time consumption compared with traditional methods reached approximately 50–80% in different scenarios.

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A Subdivision Method to Unify the Existing Latitude and Longitude Grids

Cited by 44 publications

References 12 publications

QRA-Grid: Quantitative Risk Analysis and Grid-based Pre-warning Model for Urban Natural Gas Pipeline

QRA-Grid: Quantitative Risk Analysis and Grid-based Pre-warning Model for Urban Natural Gas Pipeline

A Low-Altitude Flight Conflict Detection Algorithm Based on a Multilevel Grid Spatiotemporal Index

Collision Detection for UAVs Based on GeoSOT-3D Grids

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