--- theme: smartblue --- > 本文将对GeoTools相关概念进行介绍，同时会给大家分享我工作中用到的工具类及使用方法。 > > **作者：后端小肥肠** ## 1.前言 GeoTools是一个功能强大的开源GIS工具库，为地理空间数据处理和分析提供了丰富的功能和便利的接口。无论您是GIS专业人士还是对地理空间数据感兴趣的开发人员，掌握GeoTools都是必不可少的。本文将从基本概念入手，介绍GeoTools的功能和使用方法，并重点分享一些实用的工具类和技巧，希望能为您在GIS应用开发中提供帮助和启发。 ## 2. GeoTools简介 GeoTools是一个开源的Java库，用于处理和分析地理空间数据。它提供了一系列用于读取、写入、处理和可视化地理空间数据的工具和API。以下是与GeoTools相关的一些重要概念： 1. **地理空间数据（Geospatial Data）：** GeoTools主要用于处理地理空间数据，这包括地图、地形、卫星影像、矢量数据等地理信息。这些数据通常具有地理坐标信息和地理属性信息。 1. **地理坐标系统（Geographic Coordinate System，GCS）：** 地理坐标系统是用于在地球上定位点的一种方法。GeoTools支持多种地理坐标系统，包括经纬度坐标系统等。 1. **投影坐标系统（Projected Coordinate System，PCS）：** 投影坐标系统是将地球表面的地理坐标投影到平面上的一种方法。GeoTools提供了许多常用的投影方法和投影坐标系统的支持。 1. **数据格式（Data Formats）：** GeoTools支持多种地理空间数据格式，如Shapefile、GeoJSON、KML、GML等，可以方便地读取和写入这些数据格式。 1. **空间分析（Spatial Analysis）：** GeoTools提供了丰富的空间分析功能，包括缓冲区分析、空间查询、空间叠加分析等，可以帮助用户进行地理空间数据的处理和分析。总的来说，GeoTools是一个功能丰富的GIS工具库，提供了丰富的功能和工具，可以帮助用户处理和分析各种地理空间数据，并构建地理空间应用。 ## 3. Geotools使用示例 ### 3.1. 开发环境搭建 #### 3.1.1. 所需版本和工具依赖 | 版本 | | ----------- | ----------- | | Spring Boot | 2.6.14 | | GeoTools | 27-SNAPSHOT | | java | 1.8以上| | ArcGis | 10.8| 我这里用的不是GeoTools的最新版本，需要最新版本的同学可登录GeoTools的官网（[GeoTools The Open Source Java GIS Toolkit — GeoTools](https://geotools.org/ "GeoTools The Open Source Java GIS Toolkit — GeoTools")）查看最新版本和其使用规则。

如上图所示，最新版本的GeoTools跟java11适配。 #### 3.1.2. pom依赖 ``` org.geotools gt-shapefile ${geotools.version} org.geotools gt-geojson ${geotools.version} org.geotools gt-swing ${geotools.version} org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test org.springframework.boot spring-boot-starter-validation ``` ## 4. 工具类介绍 ### 4.1. 读取shp工具类 #### 4.1.1 准备数据打开ArcGis绘制面数据，我这里绘制了4490坐标系的几个面要素。

#### 4.1.2. 部分方法 1. 读取shp中的空间要素信息（wkt） ```java public static List getWktFromShp(String shpPath) { List shpList = new ArrayList<>(); SimpleFeatureCollection simpleFeatureCollection = null; try { //获取文件 File file = new File(shpPath); // 读取到数据存储中 FileDataStore dataStore = FileDataStoreFinder.getDataStore(file); // 获取特征资源 SimpleFeatureSource simpleFeatureSource = dataStore.getFeatureSource(); // 要素集合 simpleFeatureCollection = simpleFeatureSource.getFeatures(); } catch (IOException e) { e.printStackTrace(); } // 获取要素迭代器 SimpleFeatureIterator featureIterator = simpleFeatureCollection.features(); while (featureIterator.hasNext()) { // 要素对象 SimpleFeature feature = featureIterator.next(); Object geometryText = feature.getDefaultGeometry(); log.info(geometryText.toString()); shpList.add(geometryText.toString()); } featureIterator.close(); return shpList; } ``` 2. 运行结果

3. 读取shp文件并将其转换为Geojson ```java /** * 构造Geojson结构体 * @param featuresJson * @return */ public static JSONObject buildGeoJson(JSONArray featuresJson) { JSONObject Geojson = new JSONObject(); Geojson.put("type", "FeatureCollection"); Geojson.put("features", featuresJson); return Geojson; } /** * 构造Geojson的features部分单个 * * @param geoObject * @param properties * @return */ public static JSONObject buildFeature(Map geoObject, Map properties) { JSONObject featureObject = new JSONObject(); Map featureMap = new HashMap(); featureMap.put("type", "Feature"); featureMap.putAll(geoObject); featureMap.put("properties", properties); featureObject.putAll(featureMap); return featureObject; } /** * 获取空间信息并构造为Map * @param wkt * @return */ public static Map getGeoMap(String wkt) { Map geoMap = new HashMap<>(); String json = null; try { WKTReader reader = new WKTReader(); Geometry geometry = reader.read(wkt); StringWriter writer = new StringWriter(); GeometryJSON g = new GeometryJSON(); g.write(geometry, writer); geoMap.put("geometry", writer); } catch (Exception e) { e.printStackTrace(); } return geoMap; } /** * 基于shp构造geojson并返回 * * @param shpPath * @return */ public static JSONObject buildGeojsonFromShp(String shpPath) { JSONArray featureArray = new JSONArray(); // ListshpList=new ArrayList<>(); SimpleFeatureCollection simpleFeatureCollection = null; try { // 要素合集 //获取文件 File file = new File(shpPath); // 读取到数据存储中 ShapefileDataStore dataStore = (ShapefileDataStore) FileDataStoreFinder.getDataStore(file); dataStore.setCharset(Charset.forName("GBK")); // 获取特征资源 SimpleFeatureSource simpleFeatureSource = dataStore.getFeatureSource(); // 要素集合 simpleFeatureCollection = simpleFeatureSource.getFeatures(); } catch (IOException e) { e.printStackTrace(); } SimpleFeatureIterator featureIterator = simpleFeatureCollection.features(); // // 要素数量 int featureSize = simpleFeatureCollection.size(); // log.info("要素数量"+featureSize); //创建properties Map while (featureIterator.hasNext()) { // 要素对象 SimpleFeature feature = featureIterator.next(); Collection propertyCollection = (Collection) feature.getValue(); //填充属性map Map properMap = new HashMap<>(); for (Property property : propertyCollection) { if (property.getName().toString().equals("the_geom")) { continue; } properMap.put(property.getName().toString(), property.getValue()); } //获取geo信息 Object geometryText = feature.getDefaultGeometry(); Map geoMap = getGeoMap(geometryText.toString()); JSONObject featureObject = buildFeature(geoMap, properMap); featureArray.add(featureObject); } featureIterator.close(); JSONObject GeoJson = buildGeoJson(featureArray); return GeoJson; } ``` 4. 运行结果

#### 4.1.3. 完整工具类代码 ```java import lombok.extern.slf4j.Slf4j; import org.geotools.data.FileDataStore; import org.geotools.data.FileDataStoreFinder; import org.geotools.data.shapefile.ShapefileDataStore; import org.geotools.data.simple.SimpleFeatureCollection; import org.geotools.data.simple.SimpleFeatureIterator; import org.geotools.data.simple.SimpleFeatureSource; import org.geotools.geojson.geom.GeometryJSON; import org.json.simple.JSONArray; import org.json.simple.JSONObject; import org.locationtech.jts.geom.Geometry; import org.locationtech.jts.geom.GeometryFactory; import org.locationtech.jts.geom.Point; import org.locationtech.jts.io.ParseException; import org.locationtech.jts.io.WKTReader; import org.locationtech.jts.io.WKTWriter; import org.opengis.feature.Property; import org.opengis.feature.simple.SimpleFeature; import java.io.File; import java.io.IOException; import java.io.StringWriter; import java.nio.charset.Charset; import java.util.*; /** * @version 1.0 * @description: gis工具类 * @author: chenss * @date 2024-03-14 16:19 */ @Slf4j public class GisUtil { public static void main(String[] args) { JSONObject Geojson=buildGeojsonFromShp("D:\\arcgisdata\\mesh4490.shp"); log.info(Geojson.toJSONString()); // List wkts = getWktFromShp("D:\\arcgisdata\\mesh4490.shp"); // for (String wkt : wkts) { // log.info(wkt); // } } /** * 构造Geojson结构体 * @param featuresJson * @return */ public static JSONObject buildGeoJson(JSONArray featuresJson) { JSONObject Geojson = new JSONObject(); Geojson.put("type", "FeatureCollection"); Geojson.put("features", featuresJson); return Geojson; } /** * 构造Geojson的features部分单个 * * @param geoObject * @param properties * @return */ public static JSONObject buildFeature(Map geoObject, Map properties) { JSONObject featureObject = new JSONObject(); Map featureMap = new HashMap(); featureMap.put("type", "Feature"); featureMap.putAll(geoObject); featureMap.put("properties", properties); featureObject.putAll(featureMap); return featureObject; } /** * 获取空间信息并构造为Map * @param wkt * @return */ public static Map getGeoMap(String wkt) { Map geoMap = new HashMap<>(); String json = null; try { WKTReader reader = new WKTReader(); Geometry geometry = reader.read(wkt); StringWriter writer = new StringWriter(); GeometryJSON g = new GeometryJSON(); g.write(geometry, writer); geoMap.put("geometry", writer); } catch (Exception e) { e.printStackTrace(); } return geoMap; } /** * 只读取geo信息 wkt * * @param shpPath * @return */ public static List getWktFromShp(String shpPath) { List shpList = new ArrayList<>(); SimpleFeatureCollection simpleFeatureCollection = null; try { //获取文件 File file = new File(shpPath); // 读取到数据存储中 FileDataStore dataStore = FileDataStoreFinder.getDataStore(file); // 获取特征资源 SimpleFeatureSource simpleFeatureSource = dataStore.getFeatureSource(); // 要素集合 simpleFeatureCollection = simpleFeatureSource.getFeatures(); } catch (IOException e) { e.printStackTrace(); } // 获取要素迭代器 SimpleFeatureIterator featureIterator = simpleFeatureCollection.features(); while (featureIterator.hasNext()) { // 要素对象 SimpleFeature feature = featureIterator.next(); Object geometryText = feature.getDefaultGeometry(); log.info(geometryText.toString()); shpList.add(geometryText.toString()); } featureIterator.close(); return shpList; } /** * 基于shp构造geojson并返回 * * @param shpPath * @return */ public static JSONObject buildGeojsonFromShp(String shpPath) { JSONArray featureArray = new JSONArray(); // ListshpList=new ArrayList<>(); SimpleFeatureCollection simpleFeatureCollection = null; try { // 要素合集 //获取文件 File file = new File(shpPath); // 读取到数据存储中 ShapefileDataStore dataStore = (ShapefileDataStore) FileDataStoreFinder.getDataStore(file); dataStore.setCharset(Charset.forName("GBK")); // 获取特征资源 SimpleFeatureSource simpleFeatureSource = dataStore.getFeatureSource(); // 要素集合 simpleFeatureCollection = simpleFeatureSource.getFeatures(); } catch (IOException e) { e.printStackTrace(); } SimpleFeatureIterator featureIterator = simpleFeatureCollection.features(); // // 要素数量 int featureSize = simpleFeatureCollection.size(); // log.info("要素数量"+featureSize); //创建properties Map while (featureIterator.hasNext()) { // 要素对象 SimpleFeature feature = featureIterator.next(); Collection propertyCollection = (Collection) feature.getValue(); //填充属性map Map properMap = new HashMap<>(); for (Property property : propertyCollection) { if (property.getName().toString().equals("the_geom")) { continue; } properMap.put(property.getName().toString(), property.getValue()); } //获取geo信息 Object geometryText = feature.getDefaultGeometry(); Map geoMap = getGeoMap(geometryText.toString()); JSONObject featureObject = buildFeature(geoMap, properMap); featureArray.add(featureObject); } featureIterator.close(); JSONObject GeoJson = buildGeoJson(featureArray); return GeoJson; } /** * 根据给定的wkt面求出中心点，并以wkt形式返回 */ public static String calculateCenter(String wktPolygon) throws ParseException { // 创建 WKT 解析器和写入器 WKTReader reader = new WKTReader(new GeometryFactory()); WKTWriter writer = new WKTWriter(); // 解析面的几何对象 Geometry geometry = reader.read(wktPolygon); // 计算面的中心点 Point center = geometry.getCentroid(); // 将中心点转换为 WKT 格式 String wktCenter = writer.write(center); return wktCenter; } } ``` ### 4.2. 坐标转换工具类我这个坐标转换工具只应用于同椭球（本文示例为2000坐标系-EPSG：4490）坐标投影转换。已云南的投影带为33-35,对应的EPSG为4521、4522、4523。 #### 4.2.1. 准备数据 1. 准备4490、4521、4522、4523的shp

2. 获取.prj中坐标描述信息

3. 将坐标描述信息存放到常量Map中 ```java static final Map projMap=new HashMap(); static { projMap.put("4522","PROJCS["CGCS2000_3_Degree_GK_Zone_34",GEOGCS["GCS_China_Geodetic_Coordinate_System_2000",DATUM["D_China_2000",SPHEROID["CGCS2000",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Gauss_Kruger"],PARAMETER["False_Easting",34500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",102.0],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]"); projMap.put("4490","GEOGCS["China Geodetic Coordinate System 2000",\n" + " DATUM["China_2000",\n" + " SPHEROID["CGCS2000",6378137,298.257222101,\n" + " AUTHORITY["EPSG","1024"]],\n" + " AUTHORITY["EPSG","1043"]],\n" + " PRIMEM["Greenwich",0,\n" + " AUTHORITY["EPSG","8901"]],\n" + " UNIT["degree",0.0174532925199433,\n" + " AUTHORITY["EPSG","9122"]],\n" + " AUTHORITY["EPSG","4490"]]"); projMap.put("4521","PROJCS["CGCS2000_3_Degree_GK_Zone_33",GEOGCS["GCS_China_Geodetic_Coordinate_System_2000",DATUM["D_China_2000",SPHEROID["CGCS2000",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Gauss_Kruger"],PARAMETER["False_Easting",33500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",99.0],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]"); projMap.put("4523","PROJCS["CGCS2000_3_Degree_GK_Zone_35",GEOGCS["GCS_China_Geodetic_Coordinate_System_2000",DATUM["D_China_2000",SPHEROID["CGCS2000",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Gauss_Kruger"],PARAMETER["False_Easting",35500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",105.0],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]"); } ``` #### 4.2.2. 完整工具类代码 ```java import lombok.extern.slf4j.Slf4j; import org.geotools.data.FeatureWriter; import org.geotools.data.FileDataStoreFactorySpi; import org.geotools.data.Transaction; import org.geotools.data.shapefile.ShapefileDataStore; import org.geotools.data.shapefile.ShapefileDataStoreFactory; import org.geotools.data.simple.SimpleFeatureIterator; import org.geotools.data.simple.SimpleFeatureSource; import org.geotools.feature.simple.SimpleFeatureTypeBuilder; import org.geotools.geometry.jts.JTS; import org.geotools.referencing.CRS; import org.locationtech.jts.geom.Geometry; import org.opengis.feature.simple.SimpleFeature; import org.opengis.feature.simple.SimpleFeatureType; import org.opengis.referencing.crs.CoordinateReferenceSystem; import org.opengis.referencing.operation.MathTransform; import java.io.File; import java.io.Serializable; import java.util.HashMap; import java.util.Locale; import java.util.Map; @Slf4j public class ProjTransUtil { static final Map projMap=new HashMap(); static { projMap.put("4522","PROJCS[\"CGCS2000_3_Degree_GK_Zone_34\",GEOGCS[\"GCS_China_Geodetic_Coordinate_System_2000\",DATUM[\"D_China_2000\",SPHEROID[\"CGCS2000\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Gauss_Kruger\"],PARAMETER[\"False_Easting\",34500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",102.0],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]"); projMap.put("4490","GEOGCS[\"China Geodetic Coordinate System 2000\",\n" + " DATUM[\"China_2000\",\n" + " SPHEROID[\"CGCS2000\",6378137,298.257222101,\n" + " AUTHORITY[\"EPSG\",\"1024\"]],\n" + " AUTHORITY[\"EPSG\",\"1043\"]],\n" + " PRIMEM[\"Greenwich\",0,\n" + " AUTHORITY[\"EPSG\",\"8901\"]],\n" + " UNIT[\"degree\",0.0174532925199433,\n" + " AUTHORITY[\"EPSG\",\"9122\"]],\n" + " AUTHORITY[\"EPSG\",\"4490\"]]"); projMap.put("4521","PROJCS[\"CGCS2000_3_Degree_GK_Zone_33\",GEOGCS[\"GCS_China_Geodetic_Coordinate_System_2000\",DATUM[\"D_China_2000\",SPHEROID[\"CGCS2000\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Gauss_Kruger\"],PARAMETER[\"False_Easting\",33500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",99.0],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]"); projMap.put("4523","PROJCS[\"CGCS2000_3_Degree_GK_Zone_35\",GEOGCS[\"GCS_China_Geodetic_Coordinate_System_2000\",DATUM[\"D_China_2000\",SPHEROID[\"CGCS2000\",6378137.0,298.257222101]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],PROJECTION[\"Gauss_Kruger\"],PARAMETER[\"False_Easting\",35500000.0],PARAMETER[\"False_Northing\",0.0],PARAMETER[\"Central_Meridian\",105.0],PARAMETER[\"Scale_Factor\",1.0],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1.0]]"); } /** * 根据传入wkt获取数据坐标系 * @param wkt * @return */ public static String getProj(String wkt){ String resEpsg=""; int lonLatStart=-1; //根据wkt字符串判断平面坐标位于哪一度带 try { for (int i = 0; i < wkt.length(); i++) { if(Integer.valueOf(wkt.charAt(i))>=48&&Integer.valueOf(wkt.charAt(i))<58){ lonLatStart=i; break; } } int lonLatEnd=wkt.indexOf(","); String projLonLat=wkt.substring(lonLatStart,lonLatEnd); String[]lonlat=projLonLat.split(" "); String projLon=lonlat[0]; if(projLon.substring(0,2).equals("33")){ resEpsg="4521"; }else if(projLon.substring(0,2).equals("34")){ resEpsg="4522"; }else if(projLon.substring(0,2).equals("35")){ resEpsg="4523"; } else return "4490"; } catch (Exception e) { log.info(wkt+"出错"); log.error(e.getMessage(),e); } return resEpsg; } /** * 坐标转换 * @param geom * @param sourceEpsg * @return */ public static Geometry lonlat2WebMactor(Geometry geom,String sourceEpsg){ try{ //这里是以OGC WKT形式定义的是World Mercator投影，网页地图一般使用该投影 CoordinateReferenceSystem crsSource=CRS.parseWKT(projMap.get(sourceEpsg)); CoordinateReferenceSystem crsTarget = CRS.parseWKT(projMap.get("4490")); // 投影转换 // MathTransform transform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, crsTarget); MathTransform transform = CRS.findMathTransform(crsSource, crsTarget); return JTS.transform(geom, transform); } catch (Exception e) { // TODO Auto-generated catch block log.error(e.getMessage(),e); return null; } } /** *给定inputshp转换为targetEpsg坐标系，并输出到outputShp位置 * @param inputShp * @param outputShp * @param targetEpsg * @return */ public static Map projectShape(String inputShp, String outputShp,String targetEpsg){ Map map = new HashMap(); try { //源shape文件 ShapefileDataStore shapeDS = (ShapefileDataStore) new ShapefileDataStoreFactory().createDataStore(new File(inputShp).toURI().toURL()); //创建目标shape文件对象 Map params = new HashMap(); FileDataStoreFactorySpi factory = new ShapefileDataStoreFactory(); File file=FileUtil.createFileByPath(outputShp); // if(!file.exists()){ params.put(ShapefileDataStoreFactory.URLP.key,file.toURI().toURL()); ShapefileDataStore ds = (ShapefileDataStore) factory.createNewDataStore(params); // Charset charset = Charset.forName("UTF-8"); // ds.setCharset(charset); // 设置属性 SimpleFeatureSource fs = shapeDS.getFeatureSource(shapeDS.getTypeNames()[0]); //下面这行还有其他写法，根据源shape文件的simpleFeatureType可以不用retype，而直接用fs.getSchema设置 // CoordinateReferenceSystem crs = CRS.parseWKT(strWKTMercator); CoordinateReferenceSystem crs = CRS.parseWKT(projMap.get("4490")); ds.createSchema(SimpleFeatureTypeBuilder.retype(fs.getSchema(), crs)); //设置writer FeatureWriter writer = ds.getFeatureWriter(ds.getTypeNames()[0], Transaction.AUTO_COMMIT); //写记录 SimpleFeatureIterator it = fs.getFeatures().features(); try { while (it.hasNext()) { SimpleFeature f = it.next(); SimpleFeature fNew = writer.next(); fNew.setAttributes(f.getAttributes()); Geometry geom = lonlat2WebMactor((Geometry)f.getAttribute("the_geom"),targetEpsg); fNew.setAttribute("the_geom", geom); } } finally { it.close(); } writer.write(); writer.close(); ds.dispose(); shapeDS.dispose(); // } map.put("status", "success"); map.put("message", outputShp); } catch (Exception e) { log.error(e.getMessage(),e); map.put("status", "failure"); map.put("message", e.getMessage()); } return map; } // public static void main(String[] args) { // String input="D:\\jsonshp\\test.shp"; // String output="D:\\jsonshp\\test4490.shp"; // projectShape(input,output); // } } ``` ## 5.结语本文对Geotools的基本概念进行了简介，之后介绍了Geotools的工具类及其具体用法。下一篇文章将讲解Postgis+Geotools+MybatisPlus实现数据的读取，写入及前端展示。对Gis开发领域感兴趣的同学可动动你们发财的小手点点关注~ 结语3.jpg

## 6. 参考链接 [常见2000坐标系对应的EPSG代号 - 知乎](https://zhuanlan.zhihu.com/p/488194364?utm_id=0 "常见2000坐标系对应的EPSG代号 - 知乎")