HopeRF RFM98W modem on uputronics shield is mounted on a Raspberry Pi.

Python code on the Pi adapted from https://github.com/mayeranalytics/pySX127x receives LoRa telemetry, formats and fowards it over loopback connection to GPS tracker server running on the same device.

Open-source GPS tracker software traccar.org or http://opengts.sourceforge.net/ receives the reconstructed GPS position reports and displays on webpage map interface.

Openstreetmap tiles or other custom map tiles are downloaded to the Pi ahead of time, and served on the Pi via Tilestache.org installed on the Pi. Map tiles in .mbtile format are created beforehand using maperitive.net and Openstreetmap data; overlayed with GPX trails of race route if required, and then stored on the Pi SD card.

The Raspberry pi is set up as a WiFi hotspot with DHCP and DNS, and serves the GPS map server to any connected devices (mobile phones, tablets) as a captive portal. This way no internet connection is needed at any point for tracking, logging or displaying positions on a map.