How to convert KML to GeoJSON using GeoTools in Java (GeoServer don't accept the result of my conversion)

Question

I have a KML File and I need convert to GeoJSON. I am using Geotools in Java for convert KML because GeoServer has problems to import KML. I can convert the files but GeoServer don't accept GeoJSON converted. When I import GeoJSON converted online, there are no problems.

Code in Java

I used this code Convert Kml with multiple features to Geojson

        FileInputStream reader = new FileInputStream(fileTmp.getAbsolutePath());
        PullParser parser = new PullParser(new KMLConfiguration(), reader, SimpleFeature.class);

        FeatureJSON featureJSON = new FeatureJSON();
        FileWriter fileWriter = new FileWriter(filename + ".geojson");
        BufferedWriter writer = new BufferedWriter(fileWriter);
        ArrayList<SimpleFeature> features = new ArrayList<>();
        SimpleFeature simpleFeature = (SimpleFeature) parser.parse();
        while (simpleFeature != null) {
            LOG.info(simpleFeature);
            features.add(simpleFeature);
            simpleFeature = (SimpleFeature) parser.parse();
        }

        SimpleFeatureCollection featureCollectionUnreprojected = DataUtilities.collection(features);
        
        featureJSON.writeFeatureCollection(featureCollectionUnreprojected, writer);

KML File

<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
<Document>
    <name>KML-Example</name>
    <gx:CascadingStyle kml:id="__managed_style_1BBDE4D1D5209F676816">
        <Style>
            <IconStyle>
                <Icon>
                    <href>https://earth.google.com/earth/rpc/cc/icon?color=1976d2&amp;id=2000&amp;scale=4</href>
                </Icon>
                <hotSpot x="64" y="128" xunits="pixels" yunits="insetPixels"/>
            </IconStyle>
            <LabelStyle>
            </LabelStyle>
            <LineStyle>
                <color>ff2f2fd3</color>
                <width>4</width>
            </LineStyle>
            <PolyStyle>
                <color>402f2fd3</color>
            </PolyStyle>
            <BalloonStyle>
                <displayMode>hide</displayMode>
            </BalloonStyle>
        </Style>
    </gx:CascadingStyle>
    <gx:CascadingStyle kml:id="__managed_style_2EA205CEFB209F676816">
        <Style>
            <IconStyle>
                <scale>1.2</scale>
                <Icon>
                    <href>https://earth.google.com/earth/rpc/cc/icon?color=1976d2&amp;id=2000&amp;scale=4</href>
                </Icon>
                <hotSpot x="64" y="128" xunits="pixels" yunits="insetPixels"/>
            </IconStyle>
            <LabelStyle>
            </LabelStyle>
            <LineStyle>
                <color>ff2f2fd3</color>
                <width>6</width>
            </LineStyle>
            <PolyStyle>
                <color>402f2fd3</color>
            </PolyStyle>
            <BalloonStyle>
                <displayMode>hide</displayMode>
            </BalloonStyle>
        </Style>
    </gx:CascadingStyle>
    <StyleMap id="__managed_style_06849BAC89209F676816">
        <Pair>
            <key>normal</key>
            <styleUrl>#__managed_style_1BBDE4D1D5209F676816</styleUrl>
        </Pair>
        <Pair>
            <key>highlight</key>
            <styleUrl>#__managed_style_2EA205CEFB209F676816</styleUrl>
        </Pair>
    </StyleMap>
    <Placemark id="0C1FAD446F209F671F2B">
        <name>Teste</name>
        <LookAt>
            <longitude>-8.071672824072024</longitude>
            <latitude>40.94572565095269</latitude>
            <altitude>554.9936597887551</altitude>
            <heading>0</heading>
            <tilt>0</tilt>
            <gx:fovy>35</gx:fovy>
            <range>469307.9708133639</range>
            <altitudeMode>absolute</altitudeMode>
        </LookAt>
        <styleUrl>#__managed_style_06849BAC89209F676816</styleUrl>
        <Polygon>
            <outerBoundaryIs>
                <LinearRing>
                    <coordinates>
                        -80.32039884287052,25.79595095231043,-440.4448477037203 -40.16540389678969,-7.859693178090486,-3537.052188699258 -7.711086121502985,41.24065720616411,-5036.3287754869 -80.32039884287052,25.79595095231043,-440.4448477037203 
                    </coordinates>
                </LinearRing>
            </outerBoundaryIs>
        </Polygon>
    </Placemark>
</Document>
</kml>

Expected

{
   "type":"FeatureCollection",
   "features":[
      {
         "type":"Feature",
         "id":"0C1FAD446F209F671F2B",
         "geometry":{
            "type":"Polygon",
            "coordinates":[
               [
                  [
                     -80.32039884287052,
                     25.79595095231043,
                     -440.4448477037203
                  ],
                  [
                     -40.16540389678969,
                     -7.859693178090486,
                     -3537.052188699258
                  ],
                  [
                     -7.711086121502985,
                     41.24065720616411,
                     -5036.3287754869
                  ],
                  [
                     -80.32039884287052,
                     25.79595095231043,
                     -440.4448477037203
                  ]
               ]
            ]
         },
         "properties":{
            "name":"Teste"
         }
      }
   ]
}

My result

{
   "type":"FeatureCollection",
   "features":[
      {
         "type":"Feature",
         "geometry":{
            "type":"Polygon",
            "coordinates":[
               [
                  [
                     -80.3204,
                     25.796,
                     -440.4448
                  ],
                  [
                     -40.1654,
                     -7.8597,
                     -3537.0522
                  ],
                  [
                     -7.7111,
                     41.2407,
                     -5036.3288
                  ],
                  [
                     -80.3204,
                     25.796,
                     -440.4448
                  ]
               ]
            ]
         },
         "properties":{
            "name":"Teste",
            "visibility":true,
            "open":true,
            "LookAt":{
               "type":"Point",
               "coordinates":[
                  -8.0717,
                  40.9457,
                  554.9937
               ]
            }
         }
      },
      {
         "type":"Feature",
         "properties":{
            "name":"KML-Example",
            "visibility":true,
            "open":true
         }
      }
   ]
}

why doesn't GeoServer accept it? – Ian Turton Apr 29 '22 at 15:12 — Ian Turton, Apr 29 '22 at 15:12

score 0 · Answer 1 · answered Apr 29 '22 at 15:35

Things have moved on since that last answer, the prefered way to do this is using DataStores:

  public static void main(String[] args) throws IOException, XMLStreamException, SAXException {

    KMLDataStore ds = new KMLDataStore(new File(args[0]));
    SimpleFeatureCollection fc = ds.getFeatureSource(ds.getTypeNames()[0]).getFeatures();
    System.out.println("read in " + fc.size() + " features");
    FileDataStore dsx = FileDataStoreFinder.getDataStore(new File("/tmp/test.geojson"));
    dsx.createSchema(fc.getSchema());
    SimpleFeatureStore source = (SimpleFeatureStore) dsx.getFeatureSource(dsx.getTypeNames()[0]);
    source.addFeatures(fc);

  }

However the KMLDatastore only reads in one feature before hitting the end of the stream. I can't check if your KML is valid as all the KML validators have gone.

Your problem is that the KMLDataStore is unsupported so while you can raise an issue against it there is no saying when it would be fixed.

Can you tell me which maven dependency contains the KMLDataStore class? — Arpit Jain, Sep 05 '22 at 10:34
https://docs.geotools.org/latest/userguide/library/data/kml.html - it's an unsupported plugin so you will need to build it yourself — Ian Turton, Sep 05 '22 at 10:36

How to convert KML to GeoJSON using GeoTools in Java (GeoServer don't accept the result of my conversion)

1 Answers1