发明名称 |
Method and system for representation and use of shape information in geographic databases |
摘要 |
<p>A system and method for storing data to represent other-than-straight map features in a computer-readable geographic database for use in a navigation system. For geographic features that are other-than-straight, a curve generated by a computable function is fitted to an image of the other-than-straight map feature. The computable function may be a polynomial equation whose shape is defined by its coefficients. In one embodiment, the polynomial equation is a type of spline curve, in particular a Bezier curve whose shape is defined by control points. The coefficients of the polynomial equation are associated with data representing the other-than-straight feature. In the case in which the polynomial equation is a Bezier curve, the control points for generating the Bezier curve are associated with the data representing the other-than-straight feature. These control points are stored in the geographic database and are used in displaying the other-than-straight geographic feature. Use of a computable function to generate other-than-straight geographic features and storing parameters to be used by the computable function has the potential for significantly reducing the storage requirements for representing other-than-straight features in a geographic database. According to a further aspect, normalized control point pairs are stored in a data structure and an index reference into the data structure is associated with data used to represent the other-than-straight geographic features, thereby resulting in further reduction in data storage requirements. <IMAGE></p> |
申请公布号 |
EP0919788(A1) |
申请公布日期 |
1999.06.02 |
申请号 |
EP19980309731 |
申请日期 |
1998.11.26 |
申请人 |
NAVIGATION TECHNOLOGIES CORPORATION |
发明人 |
MEEK, JAMES;ASHBY, RICHARD;LAMPERT, DAVID |
分类号 |
G09B29/00;G01C21/00;G01C21/32;G06T11/60;(IPC1-7):G01C21/20 |
主分类号 |
G09B29/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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