Merge pull request MobilityData#240 from carlfredl/patch-1

Add PTNA to Awesome Transit

README.md

@@ -401,6 +401,7 @@ Converters from various static schedule formats to and from GTFS.
 - [ESRI ArcGIS Public Transit Tools (GTFS)](https://github.com/Esri/public-transit-tools) - Tools for working with public transit data in ArcGIS
 - [GTFS-to-Chart](https://github.com/BlinkTagInc/gtfs-to-chart) - Creates stringline charts showing all vehicles on a transit route from GTFS data.
 - [GTFS Display](https://git.wtf-eg.de/dancesWithCycles/gtfs-display) - Analyse, monitor and maintain GTFS data ([Example instances](https://www.swingbe.de/activity/gtfs-display/)).
+- [PTNA](https://wiki.openstreetmap.org/wiki/Public_Transport_Network_Analysis) - Public Transit Nework Analysis is a open source system for finding and aggregating information about public transportation lines mapped in OSM.
 
 #### GTFS Timetable Publishing Tools