# Oban — source and model notes

Built 13 October 2026. The landscape has a **6,000 m radius**, with a 12,300 m square data envelope and true vertical scale.

## Terrain and mapped context

- Origin: Ofcom radio coordinate 56.403986, −5.485885; grid NM85012898.
- Terrain: [Mapzen/Tilezen Terrain Tiles](https://registry.opendata.aws/terrain-tiles/), zoom 12, retrieved 13 October 2026. Tile source headers include EU-DEM, SRTM, GMTED2010 and ETOPO1. Individual URLs and hashes are retained with the project source.
- Heights are resampled to a 25 m grid. That spacing is NOT a claim of native source accuracy. The DEM is not a current local survey. Its origin height is approximately 108 m, whereas the radio workbook says 122 m and the TV plan says 118 m. No artificial station-height correction is applied.
- OpenStreetMap API snapshot: buildings, roads, coastline, water, land cover and landmarks. Sea polygons are closed from mapped coastlines and set to nominal zero elevation; this is neither bathymetry nor a tide model.
- Buildings: tagged height, or tagged levels × 3 m, otherwise assumed 7 m. Woodland uses illustrative 10 m clusters within mapped polygons. Neither is a surveyed obstruction model.
- Missing surface and vegetation grids remain unknown. Terrain-only profiles do not establish a clear radio link. No Fresnel zone, earth curvature, refraction or propagation model is applied.
- Cartographic texture is generated from terrain and OSM features, not aerial photography. Courtyard holes and incomplete multipolygons are simplified.

## Mast and landmark

- [Original photographs, August 2021](https://tx.mb21.co.uk/gallery/gallerypage.php?txid=417&pageid=4087) by Jack Richardson and [April 2015](https://tx.mb21.co.uk/gallery/gallerypage.php?txid=417&pageid=2207) by Bill Wright support the visible equipment types. Photographs are not redistributed.
- Nominal 45 m lattice structure, with an illustrative upper antenna support to 49 m. Ofcom lists FM aerial centre 43 m, local FM 31 m, DAB 48 m and mean TV aerial height 47 m. Structural and aerial heights are not interchangeable.
- Bracing, widths, platforms, dishes, feed supports and exact aerial arrangements are approximate. Manufacturer, model and present dish function are unverified.
- McCaig’s Tower is at OSM relation 14044981, approximately 1.66 km from the origin. The two-tier arcade is a stylised reconstruction, not a dimensional survey. [Landmark reference](https://www.undiscoveredscotland.co.uk/oban/mccaigstower/index.html).

## Service evidence

[Ofcom radio parameters](https://www.ofcom.org.uk/tv-radio-and-on-demand/coverage-and-transmitters/radio-tech-parameters) and [TV plan](https://www.ofcom.org.uk/tv-radio-and-on-demand/coverage-and-transmitters/transmitter-frequency): archived workbooks downloaded 3 October 2026. Not live feeds. Nevis Radio's own website confirms its Oban expansion in 2025. Older photo labels identifying Oban FM are historic.

## Attribution

© OpenStreetMap contributors, ODbL. European terrain produced using Copernicus data and information funded by the European Union (EU-DEM); SRTM/GMTED courtesy of USGS; ETOPO1 from NOAA. Tiles assembled by Mapzen/Tilezen. [Full provider attribution](https://github.com/tilezen/joerd/blob/master/docs/attribution.md). Ofcom information under OGL v3.0. Three.js MIT.