问题描述
我正在尝试从坐标列表创建形状文件，看起来好像可以，但是当我试图在shapefile查看器中查看shapefile时，我的形状似乎没有坐标。另外，如果我随后将我的shapefile下载为geoJSON，它看起来像是空的：
{"type":"GeometryCollection","geometries": []}
因此，我有一个java类，首先创建一些虚拟数据，然后创建polygon SimpleFeatureType，然后将点列表转换为多边形，最后尝试将该多边形写入shapefile。我没有收到任何错误，并且在我尝试在浏览器中查看它之前，所有看起来都运行平稳。
这是我的班级，上面有一些调试照片：
import org.geotools.data.DefaultTransaction;
import org.geotools.data.Transaction;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.data.simple.SimpleFeatureStore;
import org.geotools.feature.DefaultFeatureCollection;
import org.geotools.feature.SchemaException;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.feature.simple.SimpleFeatureTypeBuilder;
import org.geotools.geometry.jts.JTSFactoryFinder;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.locationtech.jts.geom.Coordinate;
import org.locationtech.jts.geom.GeometryFactory;
import org.locationtech.jts.geom.polygon;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.util.*;
public class Main {
private static SimpleFeature toFeature(List<polygonPoint> locations,SimpleFeatureType polyGON,GeometryFactory geometryFactory) {
Coordinate[] coords = new Coordinate[locations.size()];
int i = 0;
for (polygonPoint location : locations) {
Coordinate coord = new Coordinate(location.x,location.y,0);
coords[i] = (coord);
i++;
}
polygon polygon = geometryFactory.createpolygon(coords);
System.out.println(polygon.toString());
/**
* Degub print in this point looks like this: polyGON ((60.15396170672204
* 24.665516804291176,60.1548304906673 24.67437097771886,60.156868902093464
* 24.684907435753292,60.16053593400762 24.681227944085034,60.16351621152651
* 24.677017850437107,60.1641222365678 24.670587380672547,60.163303711361145
* 24.664257803508647,60.16193970279525 24.6590194867117,60.158682674758644
* 24.65963863846621,60.15396170672204 24.665516804291176)) So looks okay so
* far...
*/
SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(polyGON);
featureBuilder.add(polygon);
return featureBuilder.buildFeature(null);
}
static class polygonPoint {
public double x;
public double y;
public polygonPoint(double x,double y) {
this.x = x;
this.y = y;
}
}
private static void initData(List<polygonPoint> locations) {
locations.add(new polygonPoint(60.1539617067220433,24.6655168042911761));
locations.add(new polygonPoint(60.1548304906673010,24.6743709777188585));
locations.add(new polygonPoint(60.1568689020934642,24.6849074357532920));
locations.add(new polygonPoint(60.1605359340076191,24.6812279440850340));
locations.add(new polygonPoint(60.1635162115265132,24.6770178504371067));
locations.add(new polygonPoint(60.1641222365677990,24.6705873806725471));
locations.add(new polygonPoint(60.1633037113611451,24.6642578035086473));
locations.add(new polygonPoint(60.1619397027952516,24.6590194867116992));
locations.add(new polygonPoint(60.1586826747586443,24.6596386384662090));
locations.add(new polygonPoint(60.1539617067220433,24.6655168042911761));
}
public static void main(String[] args) throws IOException,SchemaException {
List<polygonPoint> locations = new ArrayList<>();
initData(locations);
// create simple feature builder for the locations
SimpleFeatureTypeBuilder builder = new SimpleFeatureTypeBuilder();
builder.setName("polygonFeature");
builder.setCRS(DefaultGeographicCRS.wgs84);
builder.add(polygon.TYPENAME_polyGON,polygon.class);
SimpleFeatureType polyGON = builder.buildFeatureType();
DefaultFeatureCollection collection = new DefaultFeatureCollection();
GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null);
SimpleFeature feature = toFeature(locations,polyGON,geometryFactory);
collection.add(feature);
collection.forEach(name -> System.out.println(name));
/**
* Degub print in this point looks like this:
* SimpleFeatureImpl:polygonFeature=[SimpleFeatureImpl.Attribute:
* polygon<polygon id=fid-77f7c041_174f9627c85_-8000>=polyGON
* ((60.15396170672204 24.665516804291176,* 60.156868902093464 24.684907435753292,* 60.16351621152651 24.677017850437107,* 60.163303711361145 24.664257803508647,* 60.158682674758644 24.65963863846621,60.15396170672204 24.665516804291176))]
* So looks okay still...
*/
File shapeFile = new File(new File("2020-").getAbsolutePath() + "shapefile.shp");
Map<String,Serializable> params = new HashMap<>();
params.put("url",shapeFile.toURI().toURL());
params.put("create spatial index",Boolean.TRUE);
ShapefileDataStoreFactory dataStoreFactory = new ShapefileDataStoreFactory();
ShapefileDataStore dataStore = (ShapefileDataStore) dataStoreFactory.createNewDataStore(params);
dataStore.createSchema(polyGON);
Transaction transaction = new DefaultTransaction("create");
String typeName = dataStore.getTypeNames()[0];
SimpleFeatureSource featureSource = dataStore.getFeatureSource(typeName);
if (featureSource instanceof SimpleFeatureStore) {
SimpleFeatureStore featureStore = (SimpleFeatureStore) featureSource;
featureStore.setTransaction(transaction);
try {
featureStore.addFeatures(collection);
transaction.commit();
} catch (Exception problem) {
transaction.rollback();
} finally {
transaction.close();
}
}
}
}
然后按预期创建5个文件。但是形状不正确，什么也没显示。我正在使用以下工具进行测试：https://mapshaper.org/，但一个人可以用Google搜索一些shapefile在线查看器。
解决方法
感谢Ian Turton给出的答案，该问题已通过替换此问题得以解决：
builder.add(Polygon.TYPENAME_POLYGON,Polygon.class);
与此：
builder.add("the_geom",Polygon.class);
每当我看到某个事务未写入数据时，就会查看该事务的处理方式。您实际上做到了很好，因为在发生异常时回滚。但我强烈建议您也发送一些日志消息，指出发生了哪种异常。尤其是当您抓到通用Exception时。
请参见catch块：
if (featureSource instanceof SimpleFeatureStore) {
SimpleFeatureStore featureStore = (SimpleFeatureStore) featureSource;
featureStore.setTransaction(transaction);
try {
featureStore.addFeatures(collection);
transaction.commit();
} catch (Exception problem) {
problem.printStackTrace(System.err); // print out the stack trace of the exception
transaction.rollback();
} finally {
transaction.close();
}
}
这将至少使您有机会查看问题所在。