www . ncgia . ucsb . edu / vital Linear Referencing and Alternate Expressions of Location for Transportation
نویسندگان
چکیده
S/A Selective Availability. Deliberate degradation of GPS signal by U.S. Department of Defense. The practice was discontinued in May 2000. GPS coordinates were expected to be accurate within 100 m with S/A turned on, and about 10 m with S/A off. DGPS improves accuracy in either case.
منابع مشابه
Functional Requirements for a Comprehensive Transportation Location Referencing System
Transportation agencies manage data that is referenced in one, two, three, and four dimensions. Location referencing system (LRS) data models vary across transportation agencies and often within organizations as well. This has resulted in failed attempts and abandoned efforts to interoperate business functions and / or integrate data. A number of transportation agencies, through recognition of ...
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This paper presents the critical spatial data constructs necessary for transportation applications that use and share data expressed in one to four dimensions. These spatial data constructs include spatial measurement and storage, spatial referencing and metadata, error propagation and transformation. The theoretical foundation and the characteristics for these constructs are provided along wit...
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Multi-dimensional data (i.e., data referenced in one, two, three, and four dimensions) are often managed by transportation agencies with databases and technologies that cannot be integrated due in part to the lack of a comprehensive model for location referencing of the data. This lack of a comprehensive location referencing system data model limits organizations in implementing improved soluti...
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Linear referencing represents locations along routes, linear features with an established measurement system, using relative positions. It allows locating events along routes without segmenting it, and has been applied to manage linear features in transportation and utility. In transportation, dynamics in variant attributes such as speed limit, number of lanes, surface material, and traffic acc...
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This paper explores implementation of a Linear Referencing System (LRS) model using features of next generation Database Management Systems (DBMSs) and the proposed ODMG-93 standard for Object-Oriented DBMSs (OODBMSs). The paper presents preliinary concepts being developed through research in progress. The Linear Referencing System A data model for a Linear Referencing System (LRS) was develope...
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