Digital map shape vector encoding method and position information transfer method
First Claim
1. A method of coding shape data represented by a coordinates string using one or more processors and at least one storage device, the method comprising the steps of:
- sampling the shape data at a constant distance (L);
representing the sampled shape data by data of the constant distance (L) and data of an angle (θ
);
converting, using one or more of said one or more processors, a data string of the angle (θ
) into a data string of an deflection angle (Φ
)representing a direction difference between the angles (θ
)of adjacent sampling points;
converting, using one or more of said one or more processors, the data string of the deflection angle (Φ
) into a data string of a predicted difference value (Δ
Φ
) which is a difference between a predicted value (Sj) and the actual angle; and
variable-length-coding, using one or more of said one or more processors, the data string of the predicted difference value for storing in the at least one storage device.
0 Assignments
0 Petitions
Accused Products
Abstract
It is an object to provide a method of coding the position information of a digital map in a small data volume by utilizing a compressing and coding technique. In a coding method of coding data indicative of a shape vector on a digital map, an arithmetic processing is carried out over position information about a node string and a shape which indicate the shape vector to be represented by data having a statistical deviation, and the data having the statistical deviation are coded to reduce a data volume. It is possible to considerably decrease a transmission data volume in the case in which the vector shape of the digital map is to be transferred.
-
Citations
3 Claims
-
1. A method of coding shape data represented by a coordinates string using one or more processors and at least one storage device, the method comprising the steps of:
-
sampling the shape data at a constant distance (L); representing the sampled shape data by data of the constant distance (L) and data of an angle (θ
);converting, using one or more of said one or more processors, a data string of the angle (θ
) into a data string of an deflection angle (Φ
)representing a direction difference between the angles (θ
)of adjacent sampling points;converting, using one or more of said one or more processors, the data string of the deflection angle (Φ
) into a data string of a predicted difference value (Δ
Φ
) which is a difference between a predicted value (Sj) and the actual angle; andvariable-length-coding, using one or more of said one or more processors, the data string of the predicted difference value for storing in the at least one storage device. - View Dependent Claims (2, 3)
-
Specification