Build SimpleFeature

HBase Ganos uses the SimpleFeature class to specify spatial features. Each SimpleFeature consists of ID,Geometry object and other attributes. GeoTools API provides SimpleFeatureBuilder classes to help users create SimpleFeature objects. 

      SimpleFeatureType sft = ....; SimpleFeatureBuilder sfBuilder = new SimpleFeatureBuilder(sft); builder.set("attribute name", attribute value); ... builder.set("geom", geometry); SimpleFeature feature = builder.buildFeature(object_id + "_" + date.getTime());
Note When building SimpleFeature, Ganos generates a 128-bit UUID as the Feature ID by default. In order to save storage space, users can specify their own ID. The following statement can be used for specific methods. 

       SimpleFeature feature =... feature.getUserData().put(Hints.USE_PROVIDED_FID, java.lang.Boolean.TRUE);

Create a Geometry object

Each SimpleFeature contains a Geometry object, which indicates the spatial object of a feature. For the definition of each spatial entity object of Geometry, please refer to Official documents.

The GeoTools API provides the GeometryFactory class to help you create Geometry objects. You can create Geometry objects in the following ways:
  • Point
    • Use a Coordinate object. 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(); Coordinate coord = new Coordinate(1, 1); Point point = geometryFactory.createPoint(coord);
    • Description by WKT: WKT(Well-known text) is a text markup language used to represent the conversion between vector space objects, space reference systems and space reference systems 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(); WKTReader reader = new WKTReader(geometryFactory); Point point = (Point) reader.read("POINT (1 1)");
  • Line
    • Use a Coordinate object. 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(); Coordinate[] coords = new Coordinate[] {new Coordinate(0, 2), new Coordinate(2, 0), new Coordinate(8, 6) }; LineString line = geometryFactory.createLineString(coordinates);
    • Describe by WKT 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(); WKTReader reader = new WKTReader( geometryFactory ); LineString line = (LineString) reader.read("LINESTRING(0 2, 2 0, 8 6)");
  • Polygon
    • Use a Coordinate object. 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(); Coordinate[] coords = new Coordinate[] {new Coordinate(4, 0), new Coordinate(2, 2), new Coordinate(4, 4), new Coordinate(6, 2), new Coordinate(4, 0) }; LinearRing ring = geometryFactory.createLinearRing( coords ); LinearRing holes[] = null; // use LinearRing[] to represent holes Polygon polygon = geometryFactory.createPolygon(ring, holes );
    • Describe by WKT 
      
          GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory( null ); WKTReader reader = new WKTReader( geometryFactory ); Polygon polygon = (Polygon) reader.read("POLYGON((20 10, 30 0, 40 10, 30 20, 20 10))");

Data insertion into ApsaraDB RDS

HBase Ganos writes data by using the SimpleFeatureWriter class in the GeoTools API. SimpleFeatureWriter supports transactions and can be built by calling the getFeatureWriterAppend method of DataStore.
  • Insert a single SimpleFeature 
    
        SimpleFeatureType sft = ....; SimpleFeatureWriter writer=(SimpleFeatureWriter)ds.getFeatureWriterAppend(sft.getTypeName(), Transaction.AUTO_COMMIT); SimpleFeature toWrite=writer.next(); toWrite.setAttributes(feature.getAttributes()); toWrite.getUserData().putAll(feature.getUserData()); writer.write(); writer.close();
  • Batch insert SimpleFeature

    HBase Ganos supports batch insertion of SimpleFeature through SimpleFeatureStore classes in GeoTools API. 

    
        List<SimpleFeature> features=... SimpleFeatureStore featureStore = (SimpleFeatureStore) ds.getFeatureSource(sft.getTypeName()); List<FeatureId> featureIds = featureStore.addFeatures(new ListFeatureCollection(sft,features));