GeoTools应用-DATA

转自:http://blog.csdn.net/cdl2008sky/article/details/7266785

一、Geotools The Open Source Java GIS Toolkit

http://geotools.org/   Geotools官方网站
http://docs.geotools.org/latest/javadocs/  Geotools API在线文档
http://docs.codehaus.org/display/GEOTDOC/Home　Geotools用户指南
http://repo.opengeo.org　　　                   Geotools的maven仓库地址
http://download.osgeo.org/webdav/geotools/      maven仓库地址

POM.xml配置

<repositories>
    <repository>
        <id>osgeo</id>
        <name>Open Source Geospatial Foundation Repository</name>
        <url>http://download.osgeo.org/webdav/geotools/</url>
    </repository>
    <repository>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
        <id>opengeo</id>
        <name>OpenGeo Maven Repository</name>
        <url>http://repo.opengeo.org</url>
    </repository>
</repositories>

eg:取到gt-main.jar的依赖关系

<dependency>
    <groupId>org.geotools</groupId>
    <artifactId>gt-main</artifactId>
    <version>8.4</version>
</dependency>

二、OpenGIS 软件架构

org.geotools.data
包负责地理数据的读写(如:ShavefileReader用于读取shpfile数据)，org.geotools.geometry
包负责提供对JTs的调用接口，以将地理数据封装成JTS中定义的几何对象(Geometry)，
org.geotools.feature包负责封装空间几何要素对象(Feature)，对应于地图中一个实体，
包含:空间数据(Geometry)、属性数据(Aitribute)、参考坐标系(Refereneedsystem)、
最小外包矩形(EnveloPe)等属性，是Gls操作的核心数据模型。

Geotools 读取shp 数据格式的例子:

/**
 * 读取shap格式的文件
 *
 * @param path
 */
public void readSHP(String path) {
    ShapefileDataStore shpDataStore = null;
    try {
        shpDataStore = new ShapefileDataStore(new File(path).toURI()
                .toURL());
        shpDataStore.setStringCharset(Charset.forName("GBK"));
        // 文件名称
        String typeName = shpDataStore.getTypeNames()[0];
        FeatureSource<SimpleFeatureType, SimpleFeature> featureSource = null;
        featureSource = (FeatureSource<SimpleFeatureType, SimpleFeature>) shpDataStore
                .getFeatureSource(typeName);
        FeatureCollection<SimpleFeatureType, SimpleFeature> result = featureSource
                .getFeatures();
        SimpleFeatureType schema = result.getSchema(); // schema
        List<AttributeDescriptor> columns = schema
                .getAttributeDescriptors();
        FeatureIterator<SimpleFeature> itertor = result.features();
        /*
         * 或者使用 FeatureReader FeatureReader reader =
         * DataUtilities.reader(result); while(reader.hasNext()){
         * SimpleFeature feature = (SimpleFeature) reader.next(); }
         */
        while (itertor.hasNext()) {
            SimpleFeature feature = itertor.next();
            for (AttributeDescriptor attributeDes : columns) {
                String attributeName = attributeDes.getName().toString();// attribute
                if (attributeName.equals("the_geom"))
                    continue;
                feature.getAttribute(attributeName); // attributeValue
            }
            Geometry g = (Geometry) feature.getDefaultGeometry();// Geometry
        }
        itertor.close();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

/**
 * 读取dbf格式的文件，只存储属性值，不存储空间值
 *
 * @param path
 */
public void readDBF(String path) {
    DbaseFileReader reader = null;
    try {
        reader = new DbaseFileReader(new ShpFiles(path), false,
                Charset.forName("GBK"));
        DbaseFileHeader header = reader.getHeader();
        int numFields = header.getNumFields();
        for (int i = 0; i < numFields; i++) {
            header.getFieldName(i);
            header.getFieldType(i);// 'C','N'
            header.getFieldLength(i);
        }

        // 迭代读取记录
        while (reader.hasNext()) {
            try {
                Object[] entry = reader.readEntry();
                for (int i = 0; i < numFields; i++) {
                    String title = header.getFieldName(i);
                    Object value = entry[i];
                    String name = title.toString(); // column
                    String info = value.toString(); // value
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    } catch (Exception ex) {
        ex.printStackTrace();
    } finally {
        if (reader != null) {
            // 关闭
            try {
                reader.close();
            } catch (Exception e) {
            }
        }
    }
}

输出一个shp文件

/**
 * 创建shp文件
 *
 * @param outPath
 */
public void createShp(String outPath) {
    try {
        // 定义属性
        final SimpleFeatureType TYPE = DataUtilities.createType("Location",
                "location:Point," + "NAME:String," + "INFO:String,"
                        + "OWNER:String");
        FeatureCollection<SimpleFeatureType, SimpleFeature> collection = FeatureCollections.newCollection();
        GeometryFactory geometryFactory = new GeometryFactory();
        SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
        double latitude = Double.parseDouble("116.123456789");
        double longitude = Double.parseDouble("39.120001");
        String NAME = "运通110路";
        String INFO = "白班车,学生票有效";
        String OWNER = "001";
        //创建坐标
        Point point = geometryFactory.createPoint(new Coordinate(longitude,latitude));
        //创建属性值
        Object[] obj = {point, NAME, INFO, OWNER };
        //构造一个Feature
        SimpleFeature feature = featureBuilder.buildFeature(null, obj);
        //添加到集合
        collection.add(feature);
        // shap文件的输出路径
        File newFile = new File(outPath);
        Map<String, Serializable> params = new HashMap<String, Serializable>();
        params.put("url", (Serializable) newFile.toURI().toURL());
        params.put("create spatial index", (Serializable) Boolean.TRUE);
        ShapefileDataStoreFactory dataStoreFactory = new ShapefileDataStoreFactory();
        ShapefileDataStore newDataStore = (ShapefileDataStore) dataStoreFactory
                .createNewDataStore(params);
        newDataStore.createSchema(TYPE);
        newDataStore.setStringCharset(Charset.forName("GBK"));
        newDataStore.forceSchemaCRS(DefaultGeographicCRS.WGS84);
        String typeName = newDataStore.getTypeNames()[0];
        ShapefileFeatureLocking featureSource = (ShapefileFeatureLocking) newDataStore
                .getFeatureSource(typeName);
        // 创建一个事务
        Transaction transaction = new DefaultTransaction("create");
        featureSource.setTransaction(transaction);
        try {
            featureSource.addFeatures(collection);
            // 提交事务
            transaction.commit();
        } catch (Exception problem) {
            problem.printStackTrace();
            transaction.rollback();
        } finally {
            transaction.close();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

org.geotools.data.DataUtilities
a facade classes which can help simplify common data wrangling chores  简化繁琐的通用数据
(1)、定义属性
FeatureType TYPE = DataUtilities.createType("Location",
"location:Point," + "NAME:String," + "INFO:String,"+ "OWNER:String");

(2) DataUtilities.schema
You can use this method to quickly get a representation of a FeatureType  返回FeatureType的schema
//返回schema
DataUtilities.spec(featureType))

(3) DataUtilities.collection   Feature数组转换为Feature集合
DataUtilities has helper methods to turn almost anything into a FeatureCollection
Feature[] array; 
....
return DataUtilties.collection( array );

(4) DataUtilities.reader 格式化
convert a perfectly good collection to  FeatureReader format.
FeatureCollection collection;
FeatureReader reader = DataUtilities.reader( collection );

附:shp 格式文件介绍
Shapefile file extensions
.shp—The main file that stores the feature geometry. Required.
.shx—The index file that stores the index of the feature geometry. Required.
.dbf—The dBASE table that stores the attribute information of features. Required.There is a one-to-one relationship between geometry and attributes, which is based on record number.
.prj—The file that stores the coordinate system information. Used by ArcGIS.

DBF文件中的数据类型FieldType
代码 数据类型 允许输入的数据
B  二进制型 各种字符。
C  字符型   各种字符。
D  日期型   用于区分年、月、日的数字和一个字符，内部存储按照YYYYMMDD格式。
G  (Generalor OLE)    各种字符。
N   数值型(Numeric)    - . 0 1 2 3 4 5 6 7 8 9
L   逻辑型（Logical）? Y y N n T t F f (? 表示没有初始化)。
M   (Memo)   各种字符。