Add support for line_string_feature_to_track option to create one track per geojson LineString

Author: digitaltom

README.md

@@ -79,6 +79,10 @@ gpx_file = GPX::GeoJSON.convert_to_gpx(
 )
 ```
 
+By default, multiple *LineStrings* from the geojson file will get added as segments to the same track. If you want to create a track per *LineString*, please set 
+`line_string_feature_to_track: true` or `line_string_feature_to_track: ->(ls, trk) { ... }`
+
+
 Exporting an ActiveRecord to GPXFile (as Waypoints)
 
 ```ruby

lib/gpx/geo_json.rb

@@ -33,7 +33,7 @@ class << self
       #
       def convert_to_gpx(opts = {})
         geojson = geojson_data_from(opts)
-        gpx_file = GPX::GPXFile.new
+        gpx_file = GPX::GPXFile.new(name: opts[:name], description: opts[:description])
         add_tracks_to(gpx_file, geojson, opts)
         add_waypoints_to(gpx_file, geojson, opts)
         gpx_file
@@ -62,8 +62,12 @@ def parse_geojson_data(data)
       end
 
       def add_tracks_to(gpx_file, geojson, opts)
-        tracks = [line_strings_to_track(geojson, opts)] +
-                 multi_line_strings_to_tracks(geojson, opts)
+        tracks = if opts[:line_string_feature_to_track]
+                   line_strings_to_tracks(geojson, opts)
+                 else
+                   [line_strings_to_track_segments(geojson, opts)]
+                 end
+        tracks += multi_line_strings_to_tracks(geojson, opts)
         tracks.compact!
         gpx_file.tracks += tracks
         gpx_file.tracks.each { |t| gpx_file.update_meta_data(t) }
@@ -76,10 +80,31 @@ def add_waypoints_to(gpx_file, geojson, opts)
       end
 
       # Converts GeoJSON 'LineString' features.
-      # Current strategy is to convert each LineString into a
-      # Track Segment, returning a Track for all LineStrings.
+      # This method converts each LineString into a
+      # new Track, returning one Track for each LineString.
       #
-      def line_strings_to_track(geojson, opts)
+      def line_strings_to_tracks(geojson, opts)
+        tracks = []
+        line_strings = line_strings_in(geojson)
+        return tracks unless line_strings.any?
+
+        line_strings.each do |ls|
+          track = GPX::Track.new
+          coords = ls['geometry']['coordinates']
+          segment = coords_to_segment(coords)
+
+          opts[:line_string_feature_to_track]&.call(ls, track) if opts[:line_string_feature_to_track].is_a?(Proc)
+          track.append_segment(segment)
+          tracks << track
+        end
+        tracks
+      end
+
+      # Converts GeoJSON 'LineString' features.
+      # Current default strategy is to convert each LineString into a
+      # Track Segment, returning one Track for all LineStrings.
+      #
+      def line_strings_to_track_segments(geojson, opts)
         line_strings = line_strings_in(geojson)
         return nil unless line_strings.any?
 
@@ -88,7 +113,7 @@ def line_strings_to_track(geojson, opts)
           coords = ls['geometry']['coordinates']
           segment = coords_to_segment(coords)
 
-          opts[:line_string_feature_to_segment]&.call(ls, segment)
+          opts[:line_string_feature_to_segment]&.call(ls, segment) if opts[:line_string_feature_to_segment].is_a?(Proc)
           track.append_segment(segment)
         end
         track

tests/geojson_test.rb

@@ -54,6 +54,18 @@ def test_line_string_functionality
     assert_equal(58, pts_size)
   end
 
+  def test_line_string_functionality_with_feature_to_track
+    file = File.join(File.dirname(__FILE__), 'geojson_files/line_string_data.json')
+    gpx_file = GPX::GeoJSON.convert_to_gpx(geojson_file: file, line_string_feature_to_track: true)
+
+    assert_equal(3, gpx_file.tracks.size)
+    assert_equal(1, gpx_file.tracks.first.segments.size)
+    pts_size = gpx_file.tracks[0].segments[0].points.size +
+               gpx_file.tracks[1].segments[0].points.size +
+               gpx_file.tracks[2].segments[0].points.size
+    assert_equal(58, pts_size)
+  end
+
   def test_line_string_functionality_with_lambda
     file = File.join(File.dirname(__FILE__), 'geojson_files/line_string_data.json')
     gpx_file = GPX::GeoJSON.convert_to_gpx(