code: private LineString asLineString(List<List> coords, CrsId crsId) throws IOException {
          if (coords == null || coords.size() < 2) {
              throw new IOException("A linestring requires a valid series of coordinates (at least two coordinates)");
          }
          PointSequence coordinates = getPointSequence(coords, crsId);
          return new LineString(coordinates);
      }
docs: Parses the JSON as a linestring geometry
  
  
  @param coords The coordinates for the linestring, which is a list of coordinates (which in turn are lists of
  two values, x and y)
  @param crsId
  @return An instance of linestring
  @throws IOException if the given json does not correspond to a linestring or can be parsed as such.