使用java生成mapbox-gl可讀的vector tile

來源地址：https://www.cnblogs.com/lilei2blog/p/7830945.html
概述
mapbox-gl主要數據源來自mapbox vector tile，本文就是要闡述怎樣把postgresql中的地理空間數據轉換成vector tile，流程圖如下：

配置
該工程采用spring boot+maven，所以第一步少不了pom.xml配置：

4.0.0

<groupId>com.lilei.mvt</groupId> <artifactId>vector-server</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging><name>vector-server</name> <url>http://maven.apache.org</url><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.4.0.RELEASE</version><relativePath /> <!-- lookup parent from repository --> </parent><repositories><repository><id>ECC</id><url>https://github.com/ElectronicChartCentre/ecc-mvn-repo/raw/master/releases</url></repository> </repositories><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><java.version>1.8</java.version> </properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-freemarker</artifactId></dependency><dependency><groupId>org.webjars</groupId><artifactId>jquery</artifactId><version>2.1.4</version></dependency><!-- 數據庫 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.postgresql</groupId><artifactId>postgresql</artifactId><version>42.1.1</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.vividsolutions</groupId><artifactId>jts</artifactId><version>1.13</version></dependency><dependency><groupId>com.google.protobuf</groupId><artifactId>protobuf-java</artifactId><version>2.6.1</version></dependency><!-- https://mvnrepository.com/artifact/com.google.protobuf.nano/protobuf-javanano --><dependency><groupId>com.google.protobuf.nano</groupId><artifactId>protobuf-javanano</artifactId><version>3.0.0-alpha-4</version></dependency><dependency><groupId>no.ecc.vectortile</groupId><artifactId>java-vector-tile</artifactId><version>1.2.1</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins> </build> 添加墨卡托投影轉換工具類：

核心內容
解析地理數據，轉換成vector tile：

@Override
public byte[] getContents(String type, int x, int y, int z) {

String sql = null;if (type.equals("link")){sql = "select link_pid,name,st_astext(geom) as geom from beijing_link "+ "where " + "st_intersects(geom,st_geomfromtext(?,4326)) "+ "";}else if (type.equals("poi")){sql = "select pid,st_astext(geom) as geom from poi5 "+ "where " + "st_intersects(geom,st_geomfromtext(?,4326)) "+ "";}try {String tile = TileUtils.parseXyz2Bound(x, y, z);List<Map<String, Object>> results = jdbc.queryForList(sql, tile);VectorTileEncoder vte = new VectorTileEncoder(4096, 16, false);for (Map<String, Object> m : results) {String wkt = (String) m.get("geom");Geometry geom = new WKTReader().read(wkt);TileUtils.convert2Piexl(x, y, z, geom);m.remove("geom");vte.addFeature(type, m, geom);}return vte.encode();} catch (ParseException e) {e.printStackTrace();}return null; }

github關聯程序
程序已上傳github，地址為：https://github.com/lileialg/mvt

mapbox-gl解析后效果

總結

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