Java使用Geotools讀取shape矢量數據

       作為GIS開發者而言，矢量數據是我們經常要用到的，而shape數據是矢量數據中最常用的格式，因此解析shape數據也是作為GIS軟體開發人員必備的基礎技能，而GeoTools無疑是Java最好用來處理GIS數據的三方庫，當然這只是GeoTools的冰山一角，後面我也會慢慢的去分享GeoTools的更多用法。

        今天就簡單來梳理下shape數據的解析獲取，環境是maven工程，首先是maven依賴：

<project xmlns="//maven.apache.org/POM/4.0.0" 
xmlns:xsi="//www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="//maven.apache.org/POM/4.0.0 
//maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.dudu.liuyang</groupId>
  <artifactId>gis</artifactId>
  <version>0.0.1-SNAPSHOT</version>
 
 <repositories>
   <repository>
        <id>central</id>
        <name>aliyun maven</name>
        <url>//maven.aliyun.com/repository/central</url>
        <snapshots>
        <enabled>false</enabled>
       </snapshots>
       <releases>
        <enabled>true</enabled>
       </releases>
  </repository>

  <repository>
       <id>osgeo-releases</id>
       <name>OSGeo Nexus Release Repository</name>
       <url>//repo.osgeo.org/repository/release/</url>
       <snapshots>
         <enabled>false</enabled>
       </snapshots>
       <releases>
         <enabled>true</enabled>
       </releases>
  </repository>
    
  <repository>
       <id>osgeo-snapshots</id>
       <name>OSGeo Nexus Snapshot Repository</name>
       <url>//repo.osgeo.org/repository/snapshot/</url>
       <snapshots>
        <enabled>false</enabled>
       </snapshots>
       <releases>
        <enabled>true</enabled>
       </releases>
  </repository>
   
   <repository>
      <id>geosolutions</id>
      <name>geosolutions repository</name>
      <url>//maven.geo-solutions.it/</url>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
     <releases>
       <enabled>true</enabled>
     </releases>
    </repository>
 </repositories>
 
 
 
  <dependencies>
     <dependency>
         <groupId>org.geotools</groupId>
        <artifactId>gt-shapefile</artifactId>
        <version>25.2</version>
     </dependency>
  </dependencies>
  

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.2.8.RELEASE</version>
            </plugin>
        </plugins>
    </build>
  
</project>

View Code

下面就是簡單的程式碼操作，其實如果只是簡單的讀取，就很簡單，下面是主要程式碼。

package gis;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.geotools.data.FeatureSource;
import org.geotools.data.Query;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.type.AttributeDescriptor;
import org.opengis.feature.type.GeometryType;
import org.opengis.referencing.crs.CoordinateReferenceSystem;

/**
 * shape文件讀取
 * @author ly
 *
 */
public class ShapeFileReaderTest {

    private static final String FILE_PATH = "F:\\data\\vector\\shape\\line\\xian_sheng.shp";
    
    public static void main(String[] args) {
        File file = new File(FILE_PATH);
        readShapeFile(file);
    }
    
    /**
     * 
     * @param shpFile  傳遞的是shape文件中的.shp文件
     */
    private static void readShapeFile(File shpFile) {
        /**
         * 直接使用shapefileDatastore,如果不知道，也可以使用工廠模式(見下個方法)
         * 建議，如果確定是shape文件，就直使用shapefileDatastore
         */
        try {
            ShapefileDataStore shapefileDataStore = new ShapefileDataStore(shpFile.toURI().toURL());
            //這個typeNamae不傳遞，默認是文件名稱
            FeatureSource featuresource = shapefileDataStore.getFeatureSource(shapefileDataStore.getTypeNames()[0]);
            //讀取bbox
            ReferencedEnvelope bbox  =featuresource.getBounds();
            //讀取投影
            CoordinateReferenceSystem crs = featuresource.getSchema().getCoordinateReferenceSystem();
            //特徵總數
            int count = featuresource.getCount(Query.ALL);
            //獲取當前數據的geometry類型（點、線、面）
            GeometryType geometryType = featuresource.getSchema().getGeometryDescriptor().getType();
            //讀取要素
            SimpleFeatureCollection simpleFeatureCollection = (SimpleFeatureCollection) featuresource.getFeatures();
            //獲取當前矢量數據有哪些屬性欄位值
            List<AttributeDescriptor> attributes = simpleFeatureCollection.getSchema().getAttributeDescriptors();
            //
            SimpleFeatureIterator simpleFeatureIterator = simpleFeatureCollection.features();
            //
            while(simpleFeatureIterator.hasNext()) {
                SimpleFeature simpleFeature = simpleFeatureIterator.next();
                attributes.stream().forEach((a) -> {
                    //依次讀取這個shape中每一個屬性值，當然這個屬性值，可以處理其它業務
                    System.out.println(simpleFeature.getAttribute(a.getLocalName()));
                });
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
    
}

View Code

當然GeoTools對於shape數據的操作非常多，除了簡單的讀取，還有高級的過濾查詢，當然這個就需要藉助ECSQL(其實在我看來就是sql語句的條件查詢，只是用一種標準把它定義了出來)，還有就是對矢量數據的增刪改查，這些我都會在後期逐個分享。

Tags:

VirMach 便宜 VPS

QNews

QNews