CN111414444A

CN111414444A - Method and device for processing space-time trajectory information

Info

Publication number: CN111414444A
Application number: CN202010134144.1A
Authority: CN
Inventors: 周广一; 白硕
Original assignee: Beijing Mininglamp Software System Co ltd
Current assignee: Beijing Mininglamp Software System Co ltd
Priority date: 2020-03-02
Filing date: 2020-03-02
Publication date: 2020-07-14

Abstract

The embodiment of the application discloses a method and a device for processing spatiotemporal trajectory information. The method comprises the following steps: acquiring curve information corresponding to the first space-time trajectory information and the second space-time trajectory information to obtain first curve information and second curve information; determining the shortest distance between all points on the first curve and the second curve; determining the shortest distance between all points on the second curve and the first curve; calculating the sum of the shortest distances corresponding to all points on the first curve to obtain a first distance sum; calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum; and calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum.

Description

Method and device for processing space-time trajectory information

Technical Field

The present invention relates to the field of information processing, and in particular, to a method and an apparatus for processing spatiotemporal trajectory information.

Background

The position positioning technology is mature day by day, and has a plurality of application scenes, including base station positioning, wireless network positioning, Beidou navigation satellite positioning and other technologies, and meanwhile, due to the rise of mobile internet and internet, more and more terminal devices have the positioning function, and a large amount of information related to time and space exists in the life of people, such as road navigation, position sharing and other information, so that a large amount of track data is generated. The data truly reflects various attributes of the entity, including longitude and latitude, time, speed, direction and other attributes. The motion rule of the moving object and the behavior pattern hidden in the moving object can be found by analyzing and mining the mass track data.

Spatiotemporal trajectory (trackory) is a recorded sequence of positions and times of moving objects as an important spatiotemporal object data type and information source. The application range of the space-time trajectory covers various aspects such as human behaviors, traffic logistics, emergency evacuation management, animal habits, marketing and the like. By collecting and analyzing various spatiotemporal trajectory data. Similarity and abnormal features in the spatio-temporal trajectory data can be extracted. The analysis and mining of the similarity and the abnormal characteristics have epoch-making significance for the social development of human beings.

Before describing how to interpret the track and the track similarity, consider how to define the similarity between the points and the track. Whether a point has similarity with a space-time trajectory or not is judged mainly by finding out the shortest distance from the point to the curve. If this point is on this curve, it belongs to this curve. Then this point can be considered to be 100% similar to this curve. It is also essentially the shortest distance between a point and a point as a criterion for judgment.

The general implementation mode of the two spatiotemporal trajectory data in the aspect of judging the similarity is to find out two points with the closest distance between the two trajectories. The distance between the two points is used as a method for judging the similarity. Because any one trajectory curve is composed of coordinates sorted in time series. It is also a coordinate point in nature. If the corresponding track coordinate points are closest in distance, the method is the same as the point and track similarity judgment method. Closest to the original curve. We consider that this curved trajectory has infinitely close to the path it takes with the original curve.

In practical applications, the above methods have limitations in their application.

Disclosure of Invention

In order to solve any technical problem, embodiments of the present application provide a method and an apparatus for processing spatiotemporal trajectory information.

In order to achieve the purpose of the embodiment of the present application, an embodiment of the present application provides a method for processing spatiotemporal trajectory information, including:

acquiring curve information corresponding to the first space-time trajectory information and the second space-time trajectory information to obtain first curve information and second curve information;

determining the shortest distance between all points on the first curve and the second curve; determining the shortest distance between all points on the second curve and the first curve;

calculating the sum of the shortest distances corresponding to all points on the first curve to obtain a first distance sum; calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum;

and calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum.

In an exemplary embodiment, at least one of the first curve information and the second curve information is obtained by:

calculating the longitude and latitude in the obtained space-time trajectory information by using a preset geocentric coordinate system to obtain three-dimensional space coordinate information of each point in the space-time trajectory information;

performing projection operation of a plane rectangular coordinate system on three-dimensional space coordinate information of each point in the time-space trajectory information to obtain two-dimensional space coordinate information of each point in the time-space trajectory information;

and obtaining curve information corresponding to the space-time trajectory information by using the two-dimensional space coordinate information of each point in the space-time trajectory information.

In an exemplary embodiment, the obtaining curve information corresponding to the spatiotemporal trajectory information by using the two-dimensional space coordinate information of each point in the spatiotemporal trajectory information includes:

calculating the matching degree information of the longitude and latitude of each point and the longitude and latitude of the adjacent point;

screening at least two groups of target points with matching degrees meeting the high matching degree judgment condition;

creating at least two pieces of track information corresponding to at least two groups of target points;

selecting a point from points between two adjacent tracks in the space-time track information as a turning point of the two connected tracks;

and obtaining curve information according to the created track information and the selected turning point.

In an exemplary embodiment, the calculating the matching degree information of the longitude and latitude of each point and the longitude and latitude of the adjacent point includes:

processing the longitude and latitude information of each point by adopting a preset dichotomy calculation strategy to obtain a binary sequence of the longitude and latitude of each point;

carrying out coding operation on the binary sequence of each point to obtain a coding sequence of each point;

and calculating the matching degree of the coding sequence of each point and the coding sequence of the adjacent point.

In an exemplary embodiment, the calculating the similarity information of the first and second spatiotemporal trajectory information using the first and second distance sums includes:

calculating a sum of the first distance sum and the second distance sum;

carrying out averaging calculation on the sum obtained by calculation to obtain an average value;

and marking the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the average value.

An apparatus for processing spatiotemporal trajectory information, comprising:

the acquisition module is used for acquiring curve information corresponding to the first space-time trajectory information and the second space-time trajectory information to obtain first curve information and second curve information;

the determining module is used for determining the shortest distance between all points on the first curve and the second curve; determining the shortest distance between all points on the second curve and the first curve;

the first calculation module is used for calculating the sum of the shortest distances corresponding to all points on the first curve to obtain a first distance sum; calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum;

and the second calculation module is used for calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum.

In an exemplary embodiment, the obtaining module obtains at least one of the first curve information and the second curve information by:

In an exemplary embodiment, the obtaining module obtains curve information corresponding to the spatiotemporal trajectory information by using two-dimensional space coordinate information of each point in the spatiotemporal trajectory information, including:

In an exemplary embodiment, the obtaining module calculates the matching degree information between the longitude and latitude of each point and the longitude and latitude of the adjacent point by the following method, including:

In one exemplary embodiment, the second calculation module includes:

a first calculation unit configured to calculate a sum of the first distance sum and the second distance sum;

the second calculation unit is used for carrying out averaging calculation on the sum value obtained by calculation to obtain an average value;

and the processing unit is used for marking the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the average value.

According to the scheme provided by the embodiment of the application, curve information corresponding to first space-time trajectory information and second space-time trajectory information is obtained, first curve information and second curve information are obtained, and the shortest distance between all points on a first curve and a second curve is determined; determining the shortest distances between all points on the second curve and the first curve, and calculating the sum of the shortest distances between all points on the first curve to obtain a first distance sum; and calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum, and calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum, so that the problem that the special condition of track curve intersection cannot be calculated is solved, the number of points on two track curves is not required to be consistent, and the universality of similarity calculation is improved.

Additional features and advantages of the embodiments of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the embodiments of the application. The objectives and other advantages of the embodiments of the application may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the embodiments of the present application and are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and together with the examples of the embodiments of the present application do not constitute a limitation of the embodiments of the present application.

FIG. 1 is a flowchart of a method for processing spatiotemporal trajectory information according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a geocentric coordinate system provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of spatiotemporal trajectory curves provided by embodiments of the present application;

FIG. 4 is a schematic diagram illustrating a dichotomy of latitude and longitude information provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a point-to-curve position relationship provided in an embodiment of the present application;

fig. 6 is a block diagram of a spatiotemporal trajectory information processing apparatus according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that, in the embodiments of the present application, features in the embodiments and the examples may be arbitrarily combined with each other without conflict.

In the process of implementing the scheme of the present application, the inventors found that the following problems exist in the related art, and the specific analysis is as follows:

in the related art, the similarity judgment standard is to find two points with the closest distance on two curves, and then take the distance between the two selected points as the score of similarity judgment. If the two curves have the extreme condition of intersection, the two curves cannot be applied to the interpretation standard, and the method has limitation.

With the popularization and development of positioning technology, the production is full of a large amount of information related to space-time trajectories. Such as some navigation and location sharing, etc. Thus generating a large amount of spatiotemporal trajectory data. These data reflect various attributes of the entity including latitude and longitude, time, speed, direction, etc. By performing regularity analysis on the trajectory data, hidden behavior patterns in the data are fully mined.

Because the existing method for judging the similarity of the spatiotemporal trajectory data is old and limited, the distance between two nearest points on two curves is found out to be used as a standard for judging the similarity. The case where two trajectory curves intersect in an extremely special case is not considered. The method aims to improve the time-space trajectory similarity judging method in the related technology completely, take special conditions into consideration and fully improve the universality of judging the time-space trajectory similarity.

Fig. 1 is a flowchart of a method for processing spatiotemporal trajectory information according to an embodiment of the present disclosure. As shown in fig. 1, the method shown in fig. 1 includes:

101, acquiring curve information corresponding to first space-time trajectory information and second space-time trajectory information to obtain first curve information and second curve information;

in an exemplary embodiment, the spatiotemporal trajectory curve may be a curve composed of a series of coordinate data points, such as a curve formed by connecting points of longitude and latitude ordered in a temporal order. The curve is not a mathematically smooth curve but one of broken lines. Because all point location data are point location data, actually a curve is formed between points according to a time connection line. The main body for generating the space-time trajectory data point location is a main body, such as a person, a vehicle or other objects moving relatively.

In an exemplary embodiment, the latitude and longitude information is converted into points on a rectangular plane coordinate system, and curve information of the space-time trajectory information is obtained.

The number of points in the first curve information and the second curve information may be the same, or may be different.

Step 102, determining the shortest distance between all points on the first curve and the second curve; determining the shortest distance between all points on the second curve and the first curve;

in one exemplary embodiment, by calculating the shortest distance from all points on one curve to the second curve, it is not necessary to require whether the number of points on both curves is the same, which improves the versatility of the calculation.

103, calculating the sum of the shortest distances corresponding to all points on the first curve to obtain a first distance sum; calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum;

and 104, calculating similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum.

The method provided by the embodiment of the application obtains curve information corresponding to first space-time trajectory information and second space-time trajectory information, obtains first curve information and second curve information, and determines the shortest distance between all points on a first curve and a second curve; determining the shortest distances between all points on the second curve and the first curve, and calculating the sum of the shortest distances between all points on the first curve to obtain a first distance sum; and calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum, and calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum, so that the problem that the special condition of track curve intersection cannot be calculated is solved, the number of points on two track curves is not required to be consistent, and the universality of similarity calculation is improved.

The following describes a method provided in an embodiment of the present application:

In geodetic metrology, coordinate systems fall into two broad categories: the geocentric coordinate system and the reference-center coordinate system.

Fig. 2 is a schematic view of a geocentric coordinate system according to an embodiment of the present disclosure. As shown in fig. 2, the geocentric coordinate system is defined as the coordinate origin with the earth center as the origin, the positive z-axis from the origin to the north pole, and the positive x-axis from the origin to the longitude and latitude (0, 0). I.e. towards the point of intersection of the starting meridian plane with the equator. The y-axis is located on the equatorial plane and is at 90 degrees to the x-axis. The three axes constitute a spatial coordinate system. In the process of converting longitude and latitude coordinates into space coordinate system points, two clamping feet are very important: the latitude is an included angle 1 between the normal of the spatial point and the reference ellipsoid and the equatorial plane; the longitude is the angle 2 between the point of space and the plane of the rotation axis of the reference ellipsoid and the starting meridian plane of the reference ellipsoid.

Through the establishment of the space coordinate system, the space coordinate system points corresponding to the longitude and latitude can be roughly calculated by combining the radius distance of the equator R. The mapping from the spatial coordinate system to the planar coordinate system may be performed by some projection method, such as gaussian-kruger projection, lambert projection, etc. Thus, a common point on the rectangular coordinate system of the plane can be obtained.

The above description illustrates the principle of the conversion process, and in practical applications, the operation of converting longitude and latitude into a rectangular coordinate system point can be completed by using a product based on the above conversion principle.

FIG. 3 is a schematic diagram of a spatiotemporal trajectory curve provided by an embodiment of the present application. As shown in fig. 3, there are many point location data on the curve, but it is these five points, A, B, C, D and E respectively, that actually can really represent the trajectory. Based on the analysis, the point position which is important and necessary in real calculation can be determined, and the complexity and the time of calculation can be reduced.

The selection of important and necessary points can be done using a geohash code. The principle is that longitude and latitude are respectively processed by a geohash algorithm, and a string of 0-1 codes can be obtained by a dichotomy in nature. And then, combining the two strings into a string according to the longitude of the even number and the latitude of the odd number, and coding according to base32 to obtain a character string corresponding to a longitude and latitude coordinate. For example: (116.389550, 39.928167) encodes wx4g0 e. And finally, performing matching query according to the character string prefixes, wherein the similar expression distances of the character strings are close. For the inflection point, the prefixes of the character strings have differences, so that a proper positioning data connection line is selected to form a track curve.

Alternatively, the two-dimensional longitude and latitude coordinate points may be converted into a one-dimensional character string, that is, a code, where a certain character string represents a certain rectangular area, that is, all the longitude and latitude points in the rectangular area share a set of codes, that is, a character string.

In the following description, a specific example is used, when a location is obtained (116.389550, 39.928167) with latitude range of [ -90,90], longitude range of [ -180,180], the following operations are performed, including:

fig. 4 is a schematic processing diagram of dichotomy of longitude and latitude information provided in the embodiment of the present application. As shown in fig. 4, halving the latitude interval [ -90,90], obtaining intervals [ -90,0] and [0,90 ]; since latitude 39.928167 was at [0,90], the first dichotomy was obtained with a result of 1;

the bisection continues to be performed to obtain intervals [0,90], [0,45] and [45,90], and since 39.928167 is at [0,45], a second bisection result of 0 is obtained.

By analogy, the division is continuously carried out, and 39.928167 always belongs to a certain interval [ a, b ]. The interval a, b is always shrinking with each iteration and is approaching 39.928167 more and more.

The length of the binary stop interval also determines the length of the code and also the accuracy of the range represented.

The following describes the calculation of the shortest distance from a point to a curve:

after the projected plane rectangular coordinate system coordinates of each point space coordinate system are obtained, the distance from the point to the straight line can be calculated, and the number of the points is greatly reduced because the space track curve points are filtered by the geohash. And each important point is positioned at the turning point and the key point of the track curve. A straight line can be defined between two adjacent points.

The selection of the shortest distance can then be converted into a distance from the point of the mathematical function to the straight line in practice. The shortest distance is obtained by determining a point and the coefficients of the straight line function.

calculating a sum of the first distance sum and the second distance sum;

Fig. 5 is a schematic diagram of a point-to-curve position relationship provided in the embodiment of the present application. As shown in fig. 5, there are two trajectory curves a and B, each of which is a trajectory curve composed of a plurality of points in time sequence, where the trajectory curve has point positions of n and m, respectively. And respectively calculating the sum of the shortest distances from all the n points on the track A to the track B. Then, the sum of the shortest distances from m points on the track B to the track A is calculated. And taking the sum of the front and the back as a half of the track similarity score. Therefore, whether the two space-time trajectory curves are similar or not can be judged, and the similarity is large.

When the distance from all points on one curve to the other curve is calculated, turning points can be selected from all points on the curve, the distance from the turning points to the other curve is calculated, and the distance from all the turning points to the other curve is used as the distance from all the points on the curve to the other curve, so that on one hand, the difference of the tracks can be reflected, the accuracy and the fault tolerance rate of the scheme for judging the similarity of the two space-time tracks are greatly improved, and the calculated amount can be reduced.

The method for judging the similarity of the space-time trajectory based on the longitude and latitude point location data can improve and innovate the traditional method. The shortest distance from all points on the a curve to the b curve is calculated, and the shortest distance from all points on the b curve to the a curve is calculated. And finally, half of the sum of the two is taken, so that the accuracy and the fault tolerance rate of the scheme for judging the similarity of the two space-time trajectories are greatly improved. The special condition that the track curves are intersected is solved, and the consistency of the number of the point bits on the two track curves is not required.

An apparatus for processing spatiotemporal trajectory information, comprising:

In one exemplary embodiment, the second calculation module includes:

The device provided by the embodiment of the application acquires curve information corresponding to first space-time trajectory information and second space-time trajectory information, acquires first curve information and second curve information, and determines the shortest distance between all points on a first curve and a second curve; determining the shortest distances between all points on the second curve and the first curve, and calculating the sum of the shortest distances between all points on the first curve to obtain a first distance sum; and calculating the sum of the shortest distances corresponding to all points on the second curve to obtain a second distance sum, and calculating the similarity information of the first space-time trajectory information and the second space-time trajectory information by using the first distance sum and the second distance sum, so that the problem that the special condition of track curve intersection cannot be calculated is solved, the number of points on two track curves is not required to be consistent, and the universality of similarity calculation is improved.

It will be understood by those of ordinary skill in the art that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed by several physical components in cooperation. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as is well known to those of ordinary skill in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by a computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to those skilled in the art.

Claims

1. A method for processing spatiotemporal trajectory information, comprising:

2. The method of claim 1, wherein at least one of the first curve information and the second curve information is obtained by:

3. The method according to claim 2, wherein obtaining curve information corresponding to the spatiotemporal trajectory information by using two-dimensional space coordinate information of each point in the spatiotemporal trajectory information comprises:

4. The method of claim 3, wherein the calculating the matching degree information of the longitude and latitude of each point and the longitude and latitude of the adjacent point comprises:

5. The method of claim 1, wherein calculating similarity information between the first and second spatiotemporal trajectory information using the first and second distance sums comprises:

calculating a sum of the first distance sum and the second distance sum;

6. An apparatus for processing spatiotemporal trajectory information, comprising:

7. The apparatus of claim 6, wherein the obtaining module obtains at least one of the first curve information and the second curve information by:

8. The apparatus according to claim 7, wherein the obtaining module obtains curve information corresponding to the spatiotemporal trajectory information by using two-dimensional space coordinate information of each point in the spatiotemporal trajectory information, including:

9. The apparatus of claim 8, wherein the obtaining module calculates the matching degree information of the longitude and latitude of each point and the longitude and latitude of the adjacent point by:

10. The apparatus of claim 6, wherein the second computing module comprises: