---
title: GeoTools-创建要素Feature
date: 2023-11-19
author: ac
categries:
 - GIS
tags:
 - GeoTools
---

### GeoTools-创建要素

> csv2shp，通过csv转点shp文件，学习：
>
> 1. 如何创建`FeatureType`、`FeatureCollection`和`Features`；
> 2. 通过`GeometryFactory`构建`Points`点集；
> 3. 输出shp文件；
> 4. 设置投影。

#### 1.数据准备

下载一份[csv文件](https://docs.geotools.org/latest/userguide/_downloads/d4bcf8751cc3f33a9fb673902a960e53/locations.csv) ，内容格式如下：

```text
LAT, LON, CITY, NUMBER
46.066667, 11.116667, Trento, 140
44.9441, -93.0852, St Paul, 125
13.752222, 100.493889, Bangkok, 150
45.420833, -75.69, Ottawa, 200
44.9801, -93.251867, Minneapolis, 350
46.519833, 6.6335, Lausanne, 560
48.428611, -123.365556, Victoria, 721
-33.925278, 18.423889, Cape Town, 550
-33.859972, 151.211111, Sydney, 436
41.383333, 2.183333, Barcelona, 914
39.739167, -104.984722, Denver, 869
52.95, -1.133333, Nottingham, 800
45.52, -122.681944, Portland, 840
37.5667,129.681944,Seoul,473
50.733992,7.099814,Bonn,700,2016
```



#### 2.添加依赖

```xml
<dependencies>
    <dependency>
        <groupId>org.geotools</groupId>
        <artifactId>gt-shapefile</artifactId>
        <version>${geotools.version}</version>
    </dependency>
    <dependency>
        <groupId>org.geotools</groupId>
        <artifactId>gt-epsg-hsql</artifactId>
        <version>${geotools.version}</version>
    </dependency>
</dependencies>
<repositories>
    <repository>
        <id>osgeo</id>
        <name>OSGeo Release Repository</name>
        <url>https://repo.osgeo.org/repository/release/</url>
        <snapshots><enabled>false</enabled></snapshots>
        <releases><enabled>true</enabled></releases>
    </repository>
    <repository>
        <id>osgeo-snapshot</id>
        <name>OSGeo Snapshot Repository</name>
        <url>https://repo.osgeo.org/repository/snapshot/</url>
        <snapshots><enabled>true</enabled></snapshots>
        <releases><enabled>false</enabled></releases>
    </repository>
</repositories>
```



#### 3. 示例

```java
package learning;

import org.geotools.api.feature.simple.SimpleFeature;
import org.geotools.api.feature.simple.SimpleFeatureType;
import org.geotools.data.DataUtilities;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.geometry.jts.JTSFactoryFinder;
import org.geotools.swing.data.JFileDataStoreChooser;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.Point;

import javax.swing.*;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author ac
 * @date 2023/11/20 15:44
 */
public class Csv2Shape {
    public static void main(String[] args) throws Exception {
        // Set cross-platform look & feel for compatability
        UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());

        File file = JFileDataStoreChooser.showOpenFile("csv", null);
        if (file == null) {
            return;
        }

        /*
         * We use the DataUtilities class to create a FeatureType that will describe the data in our
         * shapefile.
         *
         * See also the createFeatureType method below for another, more flexible approach.
         *
         * 通过 DataUtilities 创建 FeatureType ，类似定义shp文件的名称、几何类型、属性字段、空间参考等信息。
         */
        final SimpleFeatureType TYPE =
                DataUtilities.createType(
                        "Location",
                        "the_geom:Point:srid=4326,"
                                + // <- the geometry attribute: Point type
                                "name:String,"
                                + // <- a String attribute
                                "number:Integer" // a number attribute
                );
        System.out.println("TYPE:" + TYPE);

        /*
         * A list to collect features as we create them.
         */
        List<SimpleFeature> features = new ArrayList<>();

        /*
         * GeometryFactory will be used to create the geometry attribute of each feature,
         * using a Point object for the location.
         * 创建几何工厂实例，要素构建者实例
         * 通过缓冲流一行行读取，解析数据，构建Point实例
         */
        GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
        SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);

        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
            /* First line of the data file is the header */
            String line = reader.readLine();
            System.out.println("Header: " + line);

            for (line = reader.readLine(); line != null; line = reader.readLine()) {
                if (line.trim().length() > 0) { // skip blank lines
                    String[] tokens = line.split("\\,");

                    double latitude = Double.parseDouble(tokens[0]);
                    double longitude = Double.parseDouble(tokens[1]);
                    String name = tokens[2].trim();
                    int number = Integer.parseInt(tokens[3].trim());

                    /* Longitude (= x coord) first ! */
                    // 创建几何实例geometry - point
                    Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

                    // 创建要素实例feature
                    //        feature
                    //        ↙    ↘
                    // geometry   properties

                    featureBuilder.add(point);
                    featureBuilder.add(name);
                    featureBuilder.add(number);
                    SimpleFeature feature = featureBuilder.buildFeature(null);
                    features.add(feature);
                }
            }
        }

        /*
         * Get an output file name and create the new shapefile
         *
         * 设置输出路径
         */
        File newFile = getNewShapeFile(file);

        // 创建数据存储工厂实例
        ShapefileDataStoreFactory dataStoreFactory = new ShapefileDataStoreFactory();

        Map<String, Serializable> params = new HashMap<>();
        params.put("url", newFile.toURI().toURL());
        params.put("create spatial index", Boolean.TRUE);

        // 创建新的数据存储，会输出shp文件
        ShapefileDataStore newDataStore = (ShapefileDataStore) dataStoreFactory.createNewDataStore(params);

        /*
         * TYPE is used as a template to describe the file contents
         * 添加类型描述
         */
        newDataStore.createSchema(TYPE);
    }
    /**
     * Prompt the user for the name and path to use for the output shapefile
     * 弹窗让用户选择新生成的shp文件的保存位置
     *
     * @param csvFile the input csv file used to create a default shapefile name
     * @return name and path for the shapefile as a new File object
     */
    private static File getNewShapeFile(File csvFile) {
        String path = csvFile.getAbsolutePath();
        String newPath = path.substring(0, path.length() - 4) + ".shp";

        JFileDataStoreChooser chooser = new JFileDataStoreChooser("shp");
        chooser.setDialogTitle("Save shapefile");
        chooser.setSelectedFile(new File(newPath));

        int returnVal = chooser.showSaveDialog(null);

        if (returnVal != JFileDataStoreChooser.APPROVE_OPTION) {
            // the user cancelled the dialog
            System.exit(0);
        }

        File newFile = chooser.getSelectedFile();
        if (newFile.equals(csvFile)) {
            System.out.println("Error: cannot replace " + csvFile);
            System.exit(0);
        }

        return newFile;
    }
}

```

















#### 参考文章

[1] Feature Tutorial https://docs.geotools.org/latest/userguide/tutorial/feature/csv2shp.html