Question

我已经将csv转换为shapefile并在地图上显示，这里的问题是我如何管理csv数据并删除行中的速度小于5，在相同的转换代码中可以做到这一点？

这是我的代码的一部分，我将csv转换为shapefile

public class Csv2shape {

public static void main(String[] args) throws Exception {
    // Set cross-platform look & feel for compatability
    UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());

    File file = JFileDataStoreChooser.showOpenFile("csv", null);
    if (file == null) {
        return;
    }
    /*
     * We use the DataUtilities class to create a FeatureType that will describe the data in our
     * shapefile.
     * 
     * See also the createFeatureType method below for another, more flexible approach.
     */
    final SimpleFeatureType TYPE = DataUtilities.createType(    "Location",
            "the_geom:Point:srid=4326," + // <- the geometry attribute: Point type
            "Date:String," +   // <- a String attribute
            "Heure:String," +   // <- a String attribute        
            "latitude:String," +   // <- a String attribute
            "vitesse:Double"   // a number attribute
    );
    System.out.println("TYPE:"+TYPE);

     /* A list to collect features as we create them.
     */
    List<SimpleFeature> features = new ArrayList<SimpleFeature>();

    /*
     * GeometryFactory will be used to create the geometry attribute of each feature,
     * using a Point object for the location.
     */
    GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();

    SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);

    BufferedReader reader = new BufferedReader(new FileReader(file));
    try {
        /* First line of the data file is the header */
        String line = reader.readLine();
        System.out.println("Header: " + line);

        for (line = reader.readLine(); line != null; line = reader.readLine()) {
            if (line.trim().length() > 0) { // skip blank lines
                String tokens[] = line.split("\\,");
                String name1 = tokens[0].trim();
                String name2 = tokens[1].trim();
                double latitude = Double.parseDouble(tokens[2]);
                double longitude = Double.parseDouble(tokens[3]);
                String name = tokens[4].trim();
                String name4 = tokens[5].trim();

                /* Longitude (= x coord) first ! */
                Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

                featureBuilder.add(point);
                featureBuilder.add(name1);
                featureBuilder.add(name2);
                featureBuilder.add(name);
                featureBuilder.add(name4);
                SimpleFeature feature = featureBuilder.buildFeature(null);
                features.add(feature);
            }
        }
    } finally {
        reader.close();
    }

    /*
     * Get an output file name and create the new shapefile
     */
    /*
     * Get an output file name and create the new shapefile
     */
    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);

    /*
     * TYPE is used as a template to describe the file contents
     */
    newDataStore.createSchema(TYPE);

Answer 1

如果我理解你的问题，你想做这样的事情：

double speed = Double.parseDouble(tokens[5].trim()); // fifth token is speed?

if(speed < 5) {
    /* Longitude (= x coord) first ! */
    Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

    /*add features .... */
}

Answer 2

我很抱歉，如果我没有表达好，但我尽我所能来描述情况....在我的情况下，我想在第一个有速度＆gt; = 5之后添加所有点，我发现如何做到这一点但问题是我必须从csv文件底部的顶部ans做同样的事情希望意味着该函数应该从底部再次开始

        boolean foundAnyRowHigherThan5 = false;
        for (line = reader.readLine(); line != null; line = reader.readLine()) {
            if (line.trim().length() > 0) { // skip blank lines
                String tokens[] = line.split("\\,");
                String name1 = tokens[0].trim();
                String name2 = tokens[1].trim();
                double latitude = Double.parseDouble(tokens[2]);
                double longitude = Double.parseDouble(tokens[3]);
                String name = tokens[4].trim();
                String speedString = tokens[5].trim();

                float speedFloat = Float.parseFloat(speedString);

              if(foundAnyRowHigherThan5 || speedFloat > 5.0) {
                // from this point forward, you will not skip lines based on speed.
                if(!foundAnyRowHigherThan5) {
                  foundAnyRowHigherThan5 = true;
                }

                /* Longitude (= x coord) first ! */
                Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

                featureBuilder.add(point);
                featureBuilder.add(name1);
                featureBuilder.add(name2);
                featureBuilder.add(name);
                featureBuilder.add(speedString);
                SimpleFeature feature = featureBuilder.buildFeature(null);
                features.add(feature);
                }
            }
        }
    } finally {
        reader.close();
    }

csv使用Java删除行

2 个答案: