HI,
I'm trying to add an attribute to all the features of a shape file. In order
to accomplish this I perform the following steps:
1) Read all the features contained in the shape file
2) Create a collection of features who are the copy of the original features
plus the extra attribute
3) Write the new collection in a new shape file.
The code I've written does not give any error, unfortunately the shape file
it generates is extremely small, and by displaying it I get an empty map.
I don't know if it can depend on the file I use as input, if it could be the
case, here the link to the file:
http://www3.istat.it/ambiente/cartografia/generalizzati/2011/com2011_g.zip
and here my code, thanks in advance:
public class GeoToolsVisualization {
public static void main(String[] args) throws Exception {
File file = JFileDataStoreChooser.showOpenFile("shp", null);
if (file == null) {
return;
}
FileDataStore store =
FileDataStoreFinder.getDataStore(file);
SimpleFeatureSource featureSource =
store.getFeatureSource(store.getTypeNames()[0]);
//Access a feature to get its type, and use this type to generate
the new type (the one with the extra attribute)
SimpleFeatureIterator it = featureSource.getFeatures().features();
SimpleFeature sf = it.next();
SimpleFeatureType sft = sf.getType();
//Create the new type using the former as a template
SimpleFeatureTypeBuilder stb = new SimpleFeatureTypeBuilder();
stb.setName("newFeatureType");
stb.setCRS(DefaultGeographicCRS.WGS84); //is this correct?
stb.addAll(sft.getAttributeDescriptors());
//Add the new attribute
stb.add("Cluster", Integer.class);
SimpleFeatureType newFeatureType = stb.buildFeatureType();
//Create the collection of new Features
SimpleFeatureBuilder sfb = new SimpleFeatureBuilder(newFeatureType);
SimpleFeatureCollection collection =
FeatureCollections.newCollection();
SimpleFeature newFeature;
it = featureSource.getFeatures().features();
while(it.hasNext() && collection.size() <= 10){ //Only then features
to make the execution faster
sf = it.next();
List<Object> lat = sf.getAttributes();
lat.add(new Integer(0));
sfb.addAll(lat);
newFeature = sfb.buildFeature(sf.getID());
collection.add(newFeature);
}
File newFile = getNewShapeFile(file);
ShapefileDataStoreFactory dataStoreFactory = new
ShapefileDataStoreFactory();
Map<String, Serializable> params = new HashMap<String,
Serializable>();
params.put("url", newFile.toURI().toURL());
params.put("create spatial index", Boolean.TRUE);
ShapefileDataStore newDataStore = (ShapefileDataStore)
dataStoreFactory.createNewDataStore(params);
newDataStore.createSchema(newFeatureType);
newDataStore.forceSchemaCRS(DefaultGeographicCRS.WGS84); //Shall I
comment this?
Transaction transaction = new DefaultTransaction("create");
String typeName = newDataStore.getTypeNames()[0];
SimpleFeatureSource newFeatureSource =
newDataStore.getFeatureSource(typeName);
if (newFeatureSource instanceof SimpleFeatureStore) {
SimpleFeatureStore featureStore = (SimpleFeatureStore)
featureSource;
featureStore.setTransaction(transaction);
try {
featureStore.addFeatures(collection);
transaction.commit();
} catch (Exception problem) {
problem.printStackTrace();
transaction.rollback();
} finally {
transaction.close();
}
} else {
System.out.println(typeName + " does not support read/write
access");
System.exit(1);
}
//Start the opertaion to display the generated file
FileDataStore store2 = FileDataStoreFinder.getDataStore(newFile);
SimpleFeatureSource featureSource2 =
store2.getFeatureSource();
MapContent map = new MapContent();
map.setTitle("Quickstart");
Style style = SLD.createSimpleStyle(featureSource2.getSchema());
Layer layer = new FeatureLayer(featureSource2, style);
map.addLayer(layer);
JMapFrame.showMap(map);
}
private static File getNewShapeFile(File oldFile) {
String path = oldFile.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 canceled the dialog
System.exit(0);
}
File newFile = chooser.getSelectedFile();
if (newFile.equals(oldFile)) {
System.out.println("Error: cannot replace " + oldFile);
System.exit(0);
}
return newFile;
}
}
Roberto
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