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In recent years, air pollution is getting more severe in China, especially fine particulate matter (PM2.5). However, ground monitoring stations are sparse and distributed unevenly, causing difficulty in analyzing the spatial variation of PM2.5 concentration over a large area. More and more research is aimed at estimating PM2.5 using global regression model, ignoring the spatial heterogeneity in PM2...
Flow path plays an important role in hydrological analysis modeling, especially in the dynamic simulation of surface flow discharge. The existing flow-path network model (FPN) can extract the flow path from random flow source point to the basin outlet and simplify the three-dimensional terrain surface to the one-dimensional representation. However, with the increasing of the number of flow source...
As the technology of obtaining geographic data continues to update, we can get geographic data more conveniently and efficiently. However, handling a large number of geographic data becomes the bottleneck of geography. As a new parallel processing technology, Cloud Computing shows an excellent performance in the big data calculation and network storage. Digital Elevation Model (DEM) shows the fluctuation...
At present, the vast majority of statistical softwares are running in a single-machine environment, and few spatial statistical services can be shared freely on the Internet. Fortunately, with the proposition of many implementation specifications of web interfaces by Open Geospatial Consortium (OGC), an increasing number of open source projects and platforms have appeared gradually. Based on GeoSquare,...
Research on data update mechanism based on geographic events provides an important foundation for ensuring data accuracy and freshness, improving data quality, and supporting the running of city. This paper studies spatial-temporal information update method, which is based on geographic events, and it studies the characteristics of different types of events and establishes the rules of update process...
In this paper, we mainly study finite-time input-to-state-stability (finite-time ISS) for the multi-agent systems with communication noise under switching interaction topologies, using the method of ISS, finite-time finite-time ISS-Lyapunov function.
In this study, we propose to simulate the dynamics of surface flow using a Topological Flow-path Network model (TFN) based on scale-adaptive DEMs (S-DEMs). This model makes full use of the high accuracy DEM data to extract topographical and hydrological characteristics from the terrain surface. It also assigns these characteristics with scale properties, thus building a stream-network-bounded scale-adaptive...
GIS is widely used in many fields and various industries, which makes sharing and interoperability of geographic information become urgent requirements of all departments in network environment. In the application field of water environment, some analysis systems of water environment have appeared. However, these systems often work in single computer, and their characters of common sharing are poor,...
User experience and satisfaction of Web services and service chain are majorly determined by the quality of services (QoS), which is critical to services selection. Geo-data services and processing services are two fundamental services types of geo-services, where geo-data services provide geo-data, and processing services process and produce data. Therefore, the data quality of geo-data provided...
Since the Web services has been widely applied in the field of GIS, geospatial information service, as a new form of GIS, is becoming more and more popular. Metadata plays a significant role in the process of description, registry and query of the geospatial information service. The metadata of the service should include adequate information, such as the functionality, price, and other quality information...
Usually, a typical city road network is very huge, including thousands upon thousands of nodes. If several cities are considered, even countrywide or larger area, the classical algorithm is very difficult to get a correct result. To solve this problem effectively, when a mass of data is given, distributed multi-level road network data is considered. It builds pyramid-liked data model, calculates the...
Geographic information service has been becoming the mainstream to provide GIS functions to users more conveniently. There are many geographic information services available among which some may have similar data and functions, thus how to choose the most proper and efficient one becomes the very problem. In recent years, more and more attention has been paid to the quality of geographic information...
How to maintain topological relationship's real-time updates and maintain dynamic topological relationship, is an important issue must be taken into account in the network analysis model. The topological relationship is very important for the spatial objects in the algorithm of network analysis, especially when add, delete and modify the spatial object geometry and attribute information dynamically...
Progressive vector data transmission is an import spatial data service for settling the contradiction between the amount of spatial data and network link. Existing work is focus on simplification with map generalization which has some problems. This paper put forward a new way for progressive vector data transmission based on overall effect, not on single geometry object. For this purpose, data model...
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