1. A city road network fusion method based on hierarchical merging is characterized by comprising the following steps:

acquiring original road network data of a region to be processed, separating main roads of different road types into first image layers of corresponding grades based on the original road network data, and separating connecting roads corresponding to the main roads into second image layers of corresponding grades;

acquiring start and stop point coordinates of each trunk road section and the corresponding connecting road section thereof, and merging the connecting road in the second map layer into the trunk road in the first map layer based on the start and stop point coordinates;

acquiring a road network merging threshold corresponding to each first image layer based on the coordinates of the start point and the stop point of each trunk road section in each merged first image layer, and fusing the trunk roads in the merged first image layer based on the road network merging threshold;

and merging each merged first image layer into the same image layer, thereby obtaining the urban road network after hierarchical merging.

2. The urban road network fusion method based on hierarchical merging as claimed in claim 1, wherein the trunk road and the connecting road each comprise a plurality of road segments, and the original road network data comprises the road type of each road segment; the road type includes: the main road comprises a plurality of first road types and the connecting road comprises a plurality of second road types;

separating the trunk roads of different road types into first image layers of corresponding levels based on the original road network data, and separating the connecting roads corresponding to the trunk roads into second image layers of corresponding levels, including:

separating the road section with the road type as the first road type into a first map layer with a corresponding grade;

and determining a trunk road associated with a first road section of which the road type is a second road type, and separating the first road section into a second map layer of a corresponding grade corresponding to the associated trunk road.

3. The urban road network fusion method based on hierarchical merging as claimed in claim 1 or 2, wherein said merging the links into the trunk road based on the start-stop point coordinates comprises:

filtering out a first type of start points and stop points with the same coordinates as those of the road sections included in the trunk road from the road sections included in the start points and the stop points of the road sections included in the second map layer corresponding to the connecting road so as to obtain a third map layer including the second type of start points and the stop points;

selecting the road sections with different unique identifiers from the second type start point and the second type stop point in the third layer from the road sections contained in the second layer corresponding to the connecting road;

and merging the selected road sections into the first image layers corresponding to the trunk roads so as to merge the connecting roads into the corresponding trunk roads.

4. The urban road network fusion method based on hierarchical merging as claimed in claim 3, wherein said obtaining a road network merging threshold corresponding to each first map layer based on coordinates of start and stop points of each road segment in each merged first map layer comprises:

in each merged first map layer, calculating a first distance value between the start point of the road section and the start point or the stop point closest to the start point, and calculating a second distance value between the stop point of the road section and the start point or the stop point closest to the stop point;

traversing each road section in the first map layer to correspondingly obtain a plurality of first distance values and second distance values;

and sequencing the first distance values and the second distance values in an ascending order according to the magnitude, and taking the first distance values or the second distance values of a preset order as a road network merging threshold corresponding to the first image layer.

5. The urban road network fusion method based on hierarchical merging as claimed in claim 4, wherein said fusing the main roads in the merged first map layer based on the road network merging threshold comprises:

setting the grade of a connecting road section contained in the merged first image layer to be the same as the grade of the first image layer;

and calculating the distance between the trunk roads with the same grade and parallel to each other in the first image layer, and if the distance is smaller than the road network merging threshold, merging the trunk roads parallel to each other into one trunk road.

6. The urban road network fusion method based on hierarchical merging as claimed in claim 5, wherein merging each merged first layer into the same layer to obtain a merged urban road network comprises:

and taking any one of the plurality of first image layers as a target image layer, and sequentially merging other first image layers into the target image layer to obtain the urban road network after hierarchical merging.

7. The urban road network fusion method based on hierarchical merging according to claim 4, wherein the preset bit order is 95% of the total bit order corresponding to ascending order.

8. The urban road network fusion method based on hierarchical merging as claimed in claim 1, wherein the original road network data is original road network data in a UTM projection coordinate system, and the original road network data in the UTM projection coordinate system is obtained by performing projection transformation on the obtained original road network data in a geocentric coordinate system.

9. A city road network fusion system based on hierarchical merging is characterized by comprising:

the classification module is used for separating trunk roads of different road types into first image layers of corresponding levels and separating connecting road sections of different road types into second image layers of corresponding levels based on the acquired original road network data of the region to be processed;

the connecting road merging module is used for acquiring the coordinates of the starting point and the stopping point of each trunk road section and the corresponding connecting road section, and merging the connecting road in the second map layer into the trunk road in the first map layer based on the coordinates of the starting point and the stopping point;

the main road fusion module is used for acquiring a road network fusion threshold corresponding to each first image layer based on the coordinates of the start point and the stop point of each main road section in each first image layer after combination, and fusing the main roads in the first image layer after combination based on the road network fusion threshold;

and the merging module is used for merging each fused first layer into the same layer so as to obtain a fused urban road network.

10. A storage medium for storing computer instructions, wherein a processor executes said computer program to implement the urban road network fusion method based on hierarchical merging according to any one of claims 1 to 8.

Background

Urban road network is an important carrier of urban ground traffic and also an important component of urban municipal infrastructure. The method aims at the spatial accessibility analysis of the traffic network, and is an important basis for realizing municipal infrastructure aided planning and intelligent analysis. However, the original road network data often has more redundancy due to the reasons that the road network data is difficult to acquire and process, the application scene to be aimed at is complex, and the like. When the original road network data is directly used for spatial reachability analysis, due to the problems of multi-line parallelism, repetition, isolated points, disconnection and the like, the reachability solving complexity of the algorithm on any element is obviously improved, and even the computation process is abnormally ended due to the limitation of hardware resources. At present, research on urban road networks mainly focuses on extraction of urban road networks oriented to remote sensing images, analysis of spatial accessibility based on simplified road networks and the like, and research on road network fusion simplification methods based on vector map data is rare.

In the prior art, common urban road network fusion is mostly processed based on ArcGIS, one is to directly adopt a merging tool in the ArcGIS and merge a plurality of parallel roads according to a reasonable threshold value, thereby realizing road network fusion; and secondly, based on ArcGIS, manual processing is adopted, namely, parallel lines are manually merged, broken line routes are supplemented, and isolated elements are deleted.

Firstly, the problem that path planning cannot be performed usually due to the fact that a merging tool in ArcGIS is directly adopted is solved, and the road after merging and simplification is greatly different from the actual situation; when the data is processed manually, and the range of the area to be processed is large, the data processing amount is remarkably increased, a large amount of data acquisition, vectorization, modeling operation and the like are required, time and labor are consumed, the workload is large, the efficiency is low, and the accuracy is low.

Disclosure of Invention

In view of the foregoing analysis, embodiments of the present invention provide a method, a system, and a storage medium for urban road network fusion based on hierarchical merging, so as to solve the problems of large workload, high human cost, low accuracy, and poor merging effect of the existing road network merging method.

In one aspect, the invention provides a city road network fusion method based on hierarchical merging, which comprises the following steps:

acquiring original road network data of a region to be processed, separating main roads of different road types into first image layers of corresponding grades based on the original road network data, and separating connecting roads corresponding to the main roads into second image layers of corresponding grades;

acquiring start and stop point coordinates of each trunk road section and the corresponding connecting road section thereof, and merging the connecting road in the second map layer into the trunk road in the first map layer based on the start and stop point coordinates;

acquiring a road network merging threshold corresponding to each first image layer based on the coordinates of the start point and the stop point of each trunk road section in each merged first image layer, and fusing the trunk roads in the merged first image layer based on the road network merging threshold;

and merging each merged first image layer into the same image layer, thereby obtaining the urban road network after hierarchical merging.

Further, the trunk road and the connecting road comprise a plurality of road segments, and the original road network data comprises the road type of each road segment; the road type includes: the main road comprises a plurality of first road types and the connecting road comprises a plurality of second road types;

separating the trunk roads of different road types into first image layers of corresponding levels based on the original road network data, and separating the connecting roads corresponding to the trunk roads into second image layers of corresponding levels, including:

separating the road section with the road type as the first road type into a first map layer with a corresponding grade;

and determining a trunk road associated with a first road section of which the road type is a second road type, and separating the first road section into a second map layer of a corresponding grade corresponding to the associated trunk road.

Further, the merging the connecting road into the trunk road based on the start-stop point coordinates includes:

filtering out a first type of start points and stop points with the same coordinates as those of the road sections included in the trunk road from the road sections included in the start points and the stop points of the road sections included in the second map layer corresponding to the connecting road so as to obtain a third map layer including the second type of start points and the stop points;

selecting the road sections with different unique identifiers from the second type start point and the second type stop point in the third layer from the road sections contained in the second layer corresponding to the connecting road;

and merging the selected road sections into the first image layers corresponding to the trunk roads so as to merge the connecting roads into the corresponding trunk roads.

Further, the obtaining a road network merging threshold corresponding to each first map layer based on the coordinates of the start point and the end point of each road segment in each merged first map layer includes:

in each merged first map layer, calculating a first distance value between the start point of the road section and the start point or the stop point closest to the start point, and calculating a second distance value between the stop point of the road section and the start point or the stop point closest to the stop point;

traversing each road section in the first map layer to correspondingly obtain a plurality of first distance values and second distance values;

and sequencing the first distance values and the second distance values in an ascending order according to the magnitude, and taking the first distance values or the second distance values of a preset order as a road network merging threshold corresponding to the first image layer.

Further, the merging the main roads in the merged first map layer based on the road network merging threshold includes:

setting the grade of a connecting road section contained in the merged first image layer to be the same as the grade of the first image layer;

and calculating the distance between the trunk roads with the same grade and parallel to each other in the first image layer, and if the distance is smaller than the road network merging threshold, merging the trunk roads parallel to each other into one trunk road.

Further, merging each of the merged first image layers into the same image layer to obtain a merged urban road network includes:

and taking any one of the plurality of first image layers as a target image layer, and sequentially merging other first image layers into the target image layer to obtain the urban road network after hierarchical merging.

Further, the preset bit number is 95% of the total bit number corresponding to the ascending order.

Further, the original road network data is original road network data in a UTM projection coordinate system, and the original road network data in the UTM projection coordinate system is obtained by performing projection conversion on the obtained original road network data in a geocentric coordinate system.

In another aspect, the present invention provides a city road network fusion system based on hierarchical merging, including:

the classification module is used for separating trunk roads of different road types into first image layers of corresponding levels and separating connecting road sections of different road types into second image layers of corresponding levels based on the acquired original road network data of the region to be processed;

the connecting road merging module is used for acquiring the coordinates of the starting point and the stopping point of each trunk road section and the corresponding connecting road section, and merging the connecting road in the second map layer into the trunk road in the first map layer based on the coordinates of the starting point and the stopping point;

the main road fusion module is used for acquiring a road network fusion threshold corresponding to each first image layer based on the coordinates of the start point and the stop point of each main road section in each first image layer after combination, and fusing the main roads in the first image layer after combination based on the road network fusion threshold;

and the merging module is used for merging each fused first layer into the same layer so as to obtain a fused urban road network.

In still another aspect, the present invention provides a storage medium for storing computer instructions, and a processor executing the computer program, so as to implement the urban road network fusion method based on hierarchical merging.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

1. the invention provides a city road network fusion method and system based on hierarchical merging, which separates main roads of different road types into a first layer of corresponding levels, separates connecting roads corresponding to the main roads into a second layer of corresponding levels, filters start points and stop points with the same coordinates as start points and stop points of road sections contained in the main roads from start points and stop points of road sections contained in the second layer to obtain a corresponding third layer, selects road sections with different unique marks with the start points and the stop points in the third layer from the road sections contained in the second layer, merges the selected road sections into the first layer to realize the connection of the main roads, thereby avoiding the problems of isolated points and broken lines caused by fusing the main roads, in addition, separates the main roads of different road types into the layers of corresponding levels for merging, the problem of multi-line parallel and repeat of the trunk roads caused by merging the trunk roads can be solved, the corresponding flow of the method can be automatically executed through a corresponding automatic program, the fusion of urban road networks is realized, and the method is rapid and efficient.

2. According to the urban road network fusion method and system based on hierarchical merging, requirements for the format and precision of the obtained original road network data are reduced through hierarchical processing of the main roads and the corresponding connecting roads in the road network, manual intervention is not needed for processing the data, universality is high, uncertainty of manual intervention is avoided, and processing efficiency of the road network data is improved.

3. According to the urban road network fusion method and system based on hierarchical merging provided by the invention, the isolated points in the road network are removed and the parallel lines are merged through the road network data fusion method based on hierarchical merging to obtain the fused road network, and the accessibility calculation based on the fused road network and the accessibility calculation based on the road network before fusion can achieve the same calculation effect and calculation precision.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a flow chart of an urban road network fusion method based on hierarchical merging according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a trunk road according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a secondary trunk according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of a highway according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an urban expressway according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an urban expressway connection according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a branch circuit according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of an urban expressway and its connections before merging according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an urban expressway before merging according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating a merged urban expressway according to an embodiment of the present invention;

FIG. 11 is a distribution histogram of a plurality of first distance values and second distance values according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a merged urban expressway according to an embodiment of the present invention

FIG. 13 is a schematic diagram of an urban road network before hierarchical merging according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of a hierarchical merged urban road network according to an embodiment of the present invention;

fig. 15 is a schematic diagram of an urban road network fusion system based on hierarchical merging according to an embodiment of the present invention.

Reference numerals:

110-a grading module; 120-link merge module; 130-trunk road fusion module; 140-merge module.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

The invention discloses a method for fusing urban road networks based on hierarchical merging. As shown in fig. 1, the method includes:

s110, obtaining original road network data of a region to be processed, separating main roads of different road types into first image layers of corresponding levels based on the original road network data, and separating connecting roads corresponding to the main roads into second image layers of corresponding levels.

And S120, acquiring coordinates of start points and stop points of each trunk road section and the corresponding connecting road section, and merging the connecting roads in the second map layer into the trunk roads in the first map layer based on the coordinates of the start points and the stop points.

S130, obtaining a road network merging threshold corresponding to each first image layer based on the coordinates of the start point and the stop point of each road section of each trunk road in each merged first image layer, and fusing the trunk roads in the merged first image layer based on the road network merging threshold.

And S140, merging each merged first layer into the same layer, thereby obtaining the urban road network after hierarchical merging.

Preferably, in S110, the original road network data of the region to be processed is obtained specifically by the following method:

the method comprises the steps of obtaining a vector map data set containing road network data of a region to be processed, selecting a boundary of the region to be processed, and utilizing the boundary to cut the extracted road network data to obtain original road network data of the region to be processed.

Specifically, the open source map data website www.openstreetmap.org is accessed through a browser, a to-be-processed area range is framed in a map, an original road network data File of the to-be-processed area is downloaded and exported, the format of the original road network data File is map.

Preferably, the method further comprises performing coordinate transformation on the original road network data, and specifically, setting an output coordinate system WGS _1984_ UTM _ Zone _50N by using a "projection" function of ArcGIS, so as to transform the original road network data in a geocentric coordinate system (WGS1984 geographic coordinate system) into the original road network data in a UTM projection coordinate system, so as to ensure that the original road network data based on subsequent processing is the original road network data in the UTM projection coordinate system.

Preferably, the trunk road and the connecting road each include a plurality of road segments, and the original road network data includes a road type to which each road segment belongs, where the road types include: the trunk road comprises a plurality of first road types and a plurality of second road types. Illustratively, the arterial road comprises a first road type including: the highway comprises a highway, an urban expressway, a main road, a secondary main road, a branch road, a small road, a residential road, an active street, a service road, a pedestrian street, a path, a bicycle lane, a pedestrian road, a ladder, a small road and other different road types, and the second road types contained in the connecting road comprise an expressway connecting ramp, an expressway connecting road, a main road connecting road, a secondary main road connecting road, a branch road connecting road and the like. The main road, the secondary road, the expressway, the urban expressway connecting road and the branch road are respectively shown in fig. 2 to 7.

Preferably, separating the trunk roads of different road types into the first map layers of the corresponding levels based on the original road network data, and separating the connection roads corresponding to the trunk roads into the second map layers of the corresponding levels, includes:

separating the road section with the road type as the first road type into a first map layer with a corresponding grade; illustratively, the first road type is an expressway, an urban expressway, a main road, a secondary road, a branch road, a small road, a residential area road, a living street, a service road, a pedestrian street, a small path, a bicycle lane or a pedestrian road, when the types of the 13 roads are 13, correspondingly, the road section of which the road type is the expressway is separated into a first map layer corresponding to the road type, the road section of which the road type is the urban expressway is separated into a first map layer corresponding to the road type, and so on, 13 first map layers corresponding to the 13 first road types are obtained.

And determining a trunk road associated with a first road section of which the road type is a second road type, and separating the first road section into a second map layer of a corresponding level corresponding to the trunk road associated with the first road section. Illustratively, the second road type is an expressway connecting ramp, an expressway connecting road, a main road connecting road, a sub-main road connecting road or a branch road connecting road, and when the types of the second roads are 5, correspondingly, the road section of which the road type is the expressway connecting ramp is separated into the second image layer of the corresponding grade corresponding to the expressway associated with the second road section, the road section of which the road type is the expressway connecting road is separated into the second image layer of the corresponding grade corresponding to the urban expressway associated with the second road section, and so on, thereby obtaining 5 second image layers corresponding to the 5 connecting roads.

Specifically, in the original road network data, the road segments included in each trunk road are bound to each other, that is, each trunk road corresponds to one road segment set, and each link road also corresponds to one road segment set. In practical application, when trunk roads and connecting roads of different road types are separated, a road set corresponding to each trunk road can be directly separated from original road network data into a first image layer of a corresponding level, and a road set corresponding to a connecting road associated with the trunk road is separated into a second image layer of a corresponding level.

Specifically, in the ArcGIS software, a tool of "partition by attribute" is used, a partition field is designated as "highway", and an original road network layer can be divided into a plurality of layers, such as a first layer at a level corresponding to a primary road (primary), a second layer at a level corresponding to a primary-road connection (primary _ link), a first layer at a level corresponding to an urban expressway (trunk), and a second layer at a level corresponding to an expressway connection. Specifically, one road type corresponds to one grade, and one grade corresponds to one first image layer or one second image layer.

Preferably, in S120, the coordinates of the start point and the stop point of each trunk road segment and the corresponding connecting road segment are obtained specifically by the following steps:

in ArcGIS software, an element break point and turn point tool is used, a point type is specified to be BOTH _ ENDS, and start and stop point coordinates of each trunk road section and a corresponding connecting road section are respectively extracted from each first layer and each second layer, so that subsequent analysis of the trunk road and the connecting road thereof and calculation of a road network merging threshold value are facilitated.

Preferably, merging the links into the corresponding trunk links based on the start-stop point coordinates includes:

and filtering out first type start points and first type stop points with the same coordinates as those of the road sections contained in the trunk road from the road sections contained in the second map layer corresponding to the connecting road so as to obtain a third map layer containing the second type start points and the second type stop points. That is, the second type start and stop points are start and stop points that do not overlap with the first layer. For example, in the ArcGIS software, taking the urban expressway (trunk) as an example, by using an "erasing" tool, taking the start/stop point of the link (trunk _ link) corresponding to the urban expressway as an input element and the start/stop point of the urban expressway (trunk) as an erasing element, the third layer including the start/stop point of the second type, which is the start/stop point existing only in the link (trunk _ link) corresponding to the urban expressway, can be obtained.

And selecting the road sections with different unique identifiers from the second type start point and the second type stop point in the third layer from the road sections contained in the second layer corresponding to the connecting road. Specifically, IN the ArcGIS software, a tool of selecting a layer according to attributes is used, a trunk _ link layer is used as an input, an OSMID is used as a filter, that is, "OSMID NOT IN (SELECT OSMID FROM trunk _ pt _ dif)" is input IN an expression, and a road section with both ends connected with a trunk road IN the third layer can be selected.

And merging the selected road sections into the first image layers corresponding to the trunk roads so as to merge the connecting roads into the corresponding trunk roads. Specifically, in the ArcGIS software, an "add" tool is used, the selected road segment with both ends connected to the trunk road in the third layer is used as an input data set, and the first layer corresponding to the urban expressway (trunk) is used as a target data set, that is, the selected road segment in the connected road can be added to the urban expressway. The urban expressway and the connecting roads thereof before merging are shown in fig. 8, the urban expressway before merging is shown in fig. 9, the urban expressway obtained after merging the corresponding connecting roads into the urban expressway is shown in fig. 10, and as can be seen from fig. 8 and 10, the merging method provided by the invention can accurately merge the connecting roads and the urban expressway, and as can be seen from fig. 9 and 10, the problem of disconnection of trunk roads can be solved when merging the corresponding connecting roads into the urban expressway.

Preferably, in S130, obtaining the road network merging threshold corresponding to each first map layer based on the coordinates of the start point and the end point of each main road segment in each merged first map layer includes:

in each first image layer after merging, a first distance value between the start point of the road section and the start point or the stop point closest to the start point is calculated, and a second distance value between the stop point of the road section and the start point or the stop point closest to the stop point is calculated.

And traversing each road section in the first map layer to correspondingly obtain a plurality of first distance values and second distance values.

For example, taking the first map layer corresponding to the urban expressway as an example, in the ArcGIS software, using a "generate proximity table" tool, the input element and the proximity element are both designated as the start point and the end point of the urban expressway (trunk), and an attribute table including the codes and distances to the nearest nodes (start point or end point) of the start point and the end point is obtained by calculation.

And sequencing the plurality of first distance values and the plurality of second distance values in an ascending order according to the magnitude, and taking the first distance value or the second distance value of a preset order as a road network merging threshold corresponding to the first image layer. Preferably, the predetermined number of bits is 95% of the total number of bits corresponding to the ascending order. For example, if there are 1000 distance values, the distance value corresponding to the 950 th order is used as the road network merging threshold corresponding to the first layer. Specifically, in the ArcGIS software, the attribute table is opened, a histogram of node distances is created by using a "create graph" function, as shown in fig. 11, distance distribution is observed, and a distance value covering 95% of an area is determined as a road network merging threshold corresponding to the first layer.

Preferably, the merging the main roads in the merged first map layer based on the road network merging threshold includes:

in order to accurately fuse the trunk road in the later period, the grade of the connecting road section contained in the merged first image layer needs to be set to be the same as the grade of the first image layer. Specifically, a road network level table including all road types is created, wherein the levels of the trunk roads and the connecting roads thereof are the same, and after being stored as an xls file, the xls file is imported into a data set including the road network level. Illustratively, an attribute table of a first layer corresponding to the urban expressway is opened, and the attribute table is connected with a road network level data set by using a 'connection and association' function and utilizing a highway field, so that the road network level field corresponding to the urban expressway can appear in the attribute table.

And calculating the distance between the trunk roads with the same grade and parallel to each other in the first image layer, and if the distance is smaller than the road network merging threshold corresponding to the first image layer, merging the trunk roads parallel to each other into a trunk road. Specifically, in the ArcGIS software, by using a 'merging separated roads' tool, the first map layer corresponding to the urban expressway is used as an input element, the road network level is used as a merging field, and the road network merging threshold is used as a merging distance, so that the integration of the urban expressway road network can be realized. Specifically, the city expressway before the fusion is shown in fig. 10, and the city expressway after the fusion is shown in fig. 12, as can be seen from fig. 12, the network after the fusion is more concise.

Preferably, in S140, merging each fused first image layer into the same image layer, so as to obtain a fused urban road network, including:

and taking any one of the plurality of first image layers as a target image layer, and sequentially merging other first image layers into the target image layer to obtain the urban road network after hierarchical merging. Specifically, in the ArcGIS software, a first map layer corresponding to a merged primary road (primary) is copied, and then a plurality of first map layers, such as a first map layer corresponding to a secondary road (secondary), a first map layer corresponding to a highway (motorway), a first map layer corresponding to a city expressway (trunk), a first map layer corresponding to a branch road (tertiary), and the like, are merged into the first map layer corresponding to the primary road by using an "add-on" tool, so that a merged complete city road network is obtained. Illustratively, the urban road network before hierarchical merging is shown in fig. 13, and the urban road network after hierarchical merging is shown in fig. 14, and it can be seen from fig. 14 that the integrated and complete urban road network is concise, and the trunk road has no problems of isolated points, broken lines, multi-line parallelism and repetition.

Preferably, in the ArcGIS software, the original road network is used as input by using an "erasing" tool, and the fused road network is used as an erasing element, so that the road processed in the fusion can be calculated and obtained, and the road processed in the fusion can be compared with the fused road network, and whether the fusion result is accurate or not can be checked.

The invention further discloses an urban road network fusion system based on hierarchical merging.

Since the system embodiment and the method embodiment are based on the same principle, the method embodiment may be referred to for the repeated points, and will not be described herein again.

Specifically, as shown in fig. 15, the system includes:

the classification module 110 is configured to separate trunk roads of different road types into first image layers of corresponding levels and separate connecting road segments of different road types into second image layers of corresponding levels based on the obtained original road network data of the region to be processed.

And a link merging module 120, configured to acquire start and stop coordinates of each trunk road segment and a corresponding link road segment thereof, and merge the link in the second map layer into the trunk road in the first map layer based on the start and stop coordinates.

And the trunk road fusion module 130 is configured to obtain a road network merging threshold corresponding to each first image layer based on the coordinates of the start and stop points of each trunk road section in each merged first image layer, and fuse the trunk roads in the merged first image layer based on the road network merging threshold.

And a merging module 140, configured to merge each merged first layer into the same layer, so as to obtain a merged city road network.

In an embodiment of the present invention, a storage medium is disclosed, which is used for storing computer instructions, and a processor executes the computer program, so as to implement the urban road network fusion method based on hierarchical merging. The storage medium may be Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art

Compared with the prior art, the urban road network fusion method and system based on hierarchical merging disclosed by the embodiment of the invention firstly separate the main roads of different road types into the first map layers of corresponding levels, separate the connecting roads corresponding to the main roads into the second map layers of corresponding levels, filter the start points and the stop points with the same coordinates as the start points and the stop points of the road sections contained in the main roads from the start points and the stop points contained in the second map layers to obtain the corresponding third map layers, select the road sections with different unique identifications as the start points and the stop points in the third map layers from the road sections contained in the second map layers, and merge the selected road sections into the first map layers to realize the connection of the main roads, thereby avoiding the problems of isolated points and broken lines caused when the roads are fused, and in addition, separate the main roads of different road types into the map layers of corresponding levels, and then merging is carried out, the problem that trunk roads are parallel and repeated in multi-line mode caused by merging of the trunk roads can be avoided, and the corresponding process of the method can be automatically executed through a corresponding automatic program, so that the fusion of urban road networks is realized, and the method is fast and efficient. Secondly, by carrying out grading processing on the trunk roads and the corresponding connecting roads in the road network, the requirements on the format and the precision of the obtained original road network data are reduced, manual intervention is not needed to process the data, the universality is strong, the uncertainty of manual intervention is avoided, and the processing efficiency of the road network data is improved. In addition, by means of the road network data fusion method based on hierarchical merging, the isolated points in the road network are removed, parallel lines are merged, the merged road network is obtained, the accessibility calculation based on the merged road network and the accessibility calculation based on the road network before merging can achieve the same calculation effect and calculation accuracy, however, due to the fact that the elements of the isolated points are reduced in the merged road network, connection of the main roads and the connecting roads is simplified, when the method is applied to scenes such as landscaping analysis, analysis efficiency and reliability of analysis results are remarkably improved.

Those skilled in the art will appreciate that all or part of the flow of the method implementing the above embodiments may be implemented by a computer program, which is stored in a computer readable storage medium, to instruct related hardware. The computer readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.