mil.nga.sf.geojson.Position.additionalElements: lost additional when FeatureConverter.toStringValue()

[alx696]

Please fill out as much known and relevant information as possible.

Version Information:

• SF GeoJSON Java Version: mil.nga.sf:sf-geojson:2.0.4
• SF GeoJSON Java Source: Central Repository
• IDE Name & Version: Android Studio
• Maven Version: Gradle
• Java Version: 8
• Platform & OS: Android 10
• Other Relevant Libraries: -

Expected Results:

• What did you expect to happen?

two additional element after FeatureConverter.toStringValue().

Observed Results:

• What happened instead?
  only one additional element.

• How often does this occur?

        List<Position> pointList = new ArrayList<>();
        for (DbTrackPoint tp : t.getPoints()) {
          pointList.add(
              new Position(
                  tp.getLon(), tp.getLat(), tp.getAlt(),
                  1d,
                  2d
              )
          );
        }
        LineString line = new LineString();
        line.setCoordinates(pointList);

        Map<String, Object> propertyMap = new LinkedHashMap<>();
        propertyMap.put("source", SOURCE);

        Feature lineFeature = new Feature(line);
        lineFeature.setProperties(propertyMap);
        featureCollection.addFeature(lineFeature);

      FileUtils.writeStringToFile(
          file,
          FeatureConverter.toStringValue(featureCollection),
          "UTF-8"
      );

But 2 lost, only 1 keep:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            114.41760627,
            30.47035912,
            14.82720947265625,
            1.0
          ],
          [
            114.41777497,
            30.47037775,
            17.23809814453125,
            1.0
          ]
...

Additional Information:

Can i add more than one additionalElements? Why only one?

[bosborn]

Simple Features only supports a x, y, z, and m value. GeoJSON supports additional elements. The Simple Features GeoJSON library LineString currently re-uses the Simple Features library LineString and is causing that loss. We'll have to see if we can change the GeoJSON LineString implementation to preserve those.

[alx696]

@bosborn Thanks for your answer! It is better to add a comment, let us know the limit.

[bosborn]

Fixed in version 3.0.0. As long as the GeoJSON objects are not converted to base simple features, additional elements are now preserved.