@Nullable
    public static Viewport forJson(final JsonNode node) {
        final Geopoint bottomLeft = Geopoint.forJson(JsonUtils.get(node, "bottomLeft"));
        final Geopoint topRight = Geopoint.forJson(JsonUtils.get(node, "topRight"));
        if (bottomLeft == null || topRight == null) {
            return null;
        }
        return new Viewport(bottomLeft, topRight);
    }
Creates a Viewport with given center which covers the area around it with given radius
main/src/main/java/cgeo/geocaching/location/Viewport.java