Efine altitude geometry
Such a representation may be a space efficient way to represent roads with a high level of accuracy, because the representation directly exploits the fact that vertical curves are parabolic. The use of parabolic arcs and line segments to represent the altitudinal component of roads may be advantageous for certain applications that require an accurate representation of road geometry. The data, indicating the altitude at a plurality of positions along roads, which are provided as an input to the Hough Transform, may be obtained from a positioning system located in a vehicle that is driven along roads, or alternatively, the data may be obtained from other sources such as by digitizing paper maps or imagery. Then, data that define the straight lines and vertical curves are stored in the geographic database to represent the altitudinal component of the geometry of the portions of the roads. The straight lines and parabolic vertical curves are determined by providing data indicating the altitude at a plurality of locations along portions of roads as an input to a Hough transform to determine the straight lines and vertical curves that coincide with the portions of the roads. To address these and other objectives, an embodiment of the present invention provides for representing the altitudinal component of the geometry of roads in a geographic database using data that indicate straight line segments and parabolic vertical curves.
![efine altitude geometry efine altitude geometry](https://study.com/cimages/multimages/16/altitudec.png)
Increasing the overall size of the geographic database may also require that systems that use the geographic database have faster and more powerful processors or more memory.Īccordingly, there is a need for a space efficient model for representing and storing altitude information relating to roads. Storing large numbers of shape points increases the overall size of the geographic database thereby increasing the cost of the data storage medium. A large number of shape points may be needed to accurately represent the actual shape of the road that has many vertical changes. One area in which there exists a need for improvement relates to the representation of altitude (or altitude changes) along a road. Data that define each of these points (e.g., latitude, longitude, and altitude) are stored in a geographic database to represent this road segment.Īlthough this way of representing roads and other linearly extending geographic features works well for many applications, there is room for improvement. For example, in the case of roads, each road segment is represented by two nodes that represent the end points of the road segment, and optionally by one or more shape points that represent points along the road segment between the two nodes.
#Efine altitude geometry series#
In many conventional geographic databases, a linearly extending geographic feature, such as a road, a river, or a state or municipal boundary, is represented using a series of discrete points. Geographic databases are also used by Internet sites to provide navigation-related features and services. Geographic databases are used in navigation systems to display maps and provide route calculation and guidance.
![efine altitude geometry efine altitude geometry](https://i.pinimg.com/originals/d5/67/c5/d567c5c0a51cb2b4f25b539a6e142caa.png)
The present invention relates generally to geographic databases and, more particularly, the present invention relates to a way to represent the altitudinal component of road geometry in a geographic database and a method for forming the representation.
![efine altitude geometry efine altitude geometry](https://www.media4math.com/sites/default/files/library_asset/images/Definition--Altitude.jpg)
09/970,265 filed on even date herewith, the entire disclosure of which is incorporated herein by reference. The present application is related to the copending application entitled “APPLICATION OF THE HOUGH TRANSFORM TO MODELING THE HORIZONTAL COMPONENT OF ROAD GEOMETRY AND COMPUTING HEADING AND CURVATURE”, Ser.