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本文帮助您快速理解Ganos MapMatching引擎的基本用法，包括扩展创建、创建路网数据、构建拓扑网络图、执行轨迹匹配等部分。

基本概念

路网（Road Network）：指描述道路交通网络结构和特性的数字化信息集合，包括了道路的位置、类型、等级、连接关系、几何形状、交通规则等多方面的信息。
节点（Node）：在路网数据中，节点通常代表道路的交叉点或端点，是道路网络中连接各边的点。
边（Edge）：在路网数据的上下文中，边是路网中连接两个节点的抽象概念。边主要用来表示两个地点之间的连接关系，而不涉及具体的道路物理特征。在无向图中，边没有方向；在有向图中，边则可以表示行驶方向。边通常会携带一些属性信息，比如长度、是否可通行等，但其核心作用是构建路网的结构框架。
路段（Segment）：路段是道路的一部分，具有实际的物理属性和地理位置信息，它是路网中连续的一段道路，可能从一个路口开始到下一个路口结束，或者是道路中具有相同特征（如车道数、限速等）的一段。路段数据比边更为详细，通常包含路面材质、宽度、坡度、车道配置、交通标志信息、路权（如是否允许转弯、直行等）等。路段是实现导航、交通分析、道路维护规划等应用的基础单位。

案例参考

创建插件

使用MapMatching函数需要您在数据库中创建ganos_mapmatching插件。

CREATE EXTENSION ganos_mapmatching CASCADE;
CREATE EXTENSION ganos_fdw CASCADE;

说明

创建ganos_mapmatching插件时，将同步安装ganos_geometry、ganos_spatialref和ganos_trajectory插件，如遇到类似ERROR: invalid extension name: "ganos_trajectory"报错，请联系我们处理。

为避免权限问题，建议您将扩展安装在public模式下。

CREATE EXTENSION ganos_mapmatching WITH SCHEMA PUBLIC CASCADE;
CREATE EXTENSION ganos_fdw WITH SCHEMA PUBLIC CASCADE;

示例一：利用自有路网数据实现道路匹配。

导入路网数据。

CREATE TABLE network (fid bigint,   -- 路段的唯一标识
                         source bigint,  -- 路段的开始节点标识
                         target bigint,  -- 路段的结束节点标识
                         cost double precision, -- 道路权重值（目前未使用）
                         geom public.geometry(LineString,4326) --路段的几何对象
);

INSERT INTO network(fid, source, target, cost, geom)
VALUES(1, 1, 2,1, st_geomfromtext('LINESTRING(2 1,2 0)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(2, 2, 1,1, st_geomfromtext('LINESTRING(2 0,2 1)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(3, 3, 1,1, st_geomfromtext('LINESTRING(3 1,2 1)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(4, 4, 3,1, st_geomfromtext('LINESTRING(4 1,3 1)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(5, 1, 5,1, st_geomfromtext('LINESTRING(2 1,2 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(6, 5, 1,1, st_geomfromtext('LINESTRING(2 2,2 1)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(7, 3, 6,1, st_geomfromtext('LINESTRING(3 1,3 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(8, 7, 8,1, st_geomfromtext('LINESTRING(0 2,1 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(9, 8, 7,1, st_geomfromtext('LINESTRING(1 2,0 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(10,5, 8,3, st_geomfromtext('LINESTRING(2 2,1 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(11,8, 5,3, st_geomfromtext('LINESTRING(1 2,2 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(12,6, 5,1, st_geomfromtext('LINESTRING(3 2,2 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(13,5, 6,1, st_geomfromtext('LINESTRING(2 2,3 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(14,6, 9,1, st_geomfromtext('LINESTRING(3 2,4 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(15,9, 6,1, st_geomfromtext('LINESTRING(4 2,3 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(16,10,5,1, st_geomfromtext('LINESTRING(2 3,2 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(17,5, 10,1, st_geomfromtext('LINESTRING(2 2,2 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(18,6, 11,1, st_geomfromtext('LINESTRING(3 2,3 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(19,10,11,1, st_geomfromtext('LINESTRING(2 3,3 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(20,11,12,1, st_geomfromtext('LINESTRING(3 3,4 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(21,13,10,1, st_geomfromtext('LINESTRING(2 4,2 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(22,10,13,1, st_geomfromtext('LINESTRING(2 3,2 4)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(23,9, 12,1, st_geomfromtext('LINESTRING(4 2,4 3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(24,12,9,1, st_geomfromtext('LINESTRING(4 3,4 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(25,9, 4,1, st_geomfromtext('LINESTRING(4 2,4 1)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(26,4, 9,1, st_geomfromtext('LINESTRING(4 1,4 2)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(27,14,15,1, st_geomfromtext('LINESTRING(0.5 3.5,2 3.5)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(28,15,14,1, st_geomfromtext('LINESTRING(2 3.5,0.5 3.5)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(29,16,17,1, st_geomfromtext('LINESTRING(3.5 4,3.5 2.3)'));
INSERT INTO network(fid, source, target, cost, geom)
VALUES(30,17,16,1, st_geomfromtext('LINESTRING(3.5 2.3,3.5 4)'));

构建地图匹配工作空间。

SELECT st_createworkspace('mm_ws_test1', 'select fid, source, target, geom from network');

工作空间中生成的路网结构如下：

创建待匹配的轨迹线数据。

CREATE TABLE traj(id int, geom geometry(linestring, 4326));
INSERT INTO traj(id, geom)
VALUES(1,st_geomfromtext('LINESTRING(4.15 1.6,3.47 0.92,2.4 0.92,2.14 1.53,2.14 2.57,2.49 2.98)'));

执行道路匹配。

SELECT st_astext(st_mapmatching('mm_ws_test1', geom, '{"algorithm":"stmatch","k":4,"r":0.25,"e":0.5}'::text)) AS geom
FROM traj;

返回结果如下：

                     geom                     
----------------------------------------------
 LINESTRING(4 1.6,4 1,3 1,2 1,2 2,2 3,2.49 3)
(1 row)

示例二：利用OSM数据实现道路匹配。

导入OSM数据。

-- 导入OSS上的OSM路网数据，目前只支持导入OSS上的源文件
-- accesskeyid,accesskeysecret为OSS的访问密钥
-- directory指文件夹，如果在根目录下可不填
SELECT st_regforeigntables('OSS://{accesskeyid}:{accesskeysecret}@{endpoint}/{bucket}/{directory}/macau-latest.osm.pbf' , 'osmserver', 'OSMNT');
SELECT st_setcplconfig('OSS_ENDPOINT', '{endpoint}');

-- 提取路网节点数据
CREATE TABLE macau_network_nodes
(
    id     BIGSERIAL,
    fid    BIGINT,
    eout   INTEGER,
    lon    DOUBLE PRECISION ,
    lat    DOUBLE PRECISION,
    cnt    INTEGER,
    chk    INTEGER,
    ein    INTEGER,
    name   text,
    tags   text,
    point  GEOMETRY(point, 4326)
);

INSERT INTO macau_network_nodes(fid, lon, lat, name, tags, point)
SELECT osm_id::bigint, ST_X(geom), ST_Y(geom), name, to_json(other_tags)::jsonb, geom
FROM points;

-- 提取路网边数据
CREATE TABLE macau_network_ways
(
    gid               BIGSERIAL,
    fid            BIGINT,
    length            DOUBLE PRECISION,
    length_m          DOUBLE PRECISION,
    p                 TEXT,
    source            BIGINT,
    target            BIGINT,
    source_osm        BIGINT,
    target_osm        BIGINT,
    cost              DOUBLE PRECISION,
    reverse_cost      DOUBLE PRECISION DEFAULT -1,
    cost_s            DOUBLE PRECISION,
    reverse_cost_s    DOUBLE PRECISION DEFAULT -1,
    rule              TEXT,
    one_way           INT,
    oneway            TEXT,
    x1                DOUBLE PRECISION,
    y1                DOUBLE PRECISION,
    x2                DOUBLE PRECISION,
    y2                DOUBLE PRECISION,
    maxspeed_forward  DOUBLE PRECISION,
    maxspeed_backward DOUBLE PRECISION DEFAULT -1,
    priority          DOUBLE PRECISION DEFAULT 1,
    name              TEXT,
    tags              JSONB,
    linestring        GEOMETRY(LINESTRING, 4326)
);

INSERT INTO macau_network_ways(fid, source_osm, target_osm, name, tags, linestring)
SELECT osm_id::bigint, source_osm, target_osm, name, to_json(other_tags)::jsonb, geom
FROM lines;

构造路网数据。

-- 更新路网起止节点ID
UPDATE macau_network_ways
SET source = macau_network_nodes.id
FROM macau_network_nodes
WHERE macau_network_ways.source_osm = macau_network_nodes.fid;

UPDATE macau_network_ways
SET target = macau_network_nodes.id
FROM macau_network_nodes
WHERE macau_network_ways.target_osm = macau_network_nodes.fid;

构建地图匹配工作空间。

SELECT st_createworkspace('mm_ws_test2', 'select fid, source, target, linestring from macau_network_ways');

执行道路匹配。

SELECT st_astext(st_mapmatching('mm_ws_test2', 'LINESTRING(113.5492 22.1881,113.5493 22.1881,113.5504 22.1885,113.5505 22.1886,113.5502 22.189,113.5501 22.1891,113.5491 22.1887,113.5489 22.1887)', '{"algorithm":"stmatch","k":4,"r":0.25,"e":0.5,"tolerance":0.5,"vmax":1.0,"factor":0.5}'::text));

返回结果如下：

LINESTRING(113.5492633 22.1880942,113.5493491 22.1881266,113.5504129 22.1885289,113.5505378 22.1885762,113.5502504 22.1892274,113.5505378 22.1885762,113.5502504 22.1892274,113.5501282 22.1891812,113.5490843 22.1887864,113.5489761 22.1887455)