Fiber route maps in the conference record

A practice note on extracting and georeferencing operator route maps from conference slides

Sunday, August 16, 2026

This note is also available as a typeset PDF.

Operators have been putting maps of their fiber builds on conference slides for thirty years. Most of those maps were shown once and filed away. This note describes finding them in the collection, judging which of them carry real geographic information, and tracing that information back out into standard geographic form — KML aligned against present-day OpenStreetMap data.

From roughly 1.2 million archived slide and document pages, a text pass over the page descriptions produced 3,806 candidates; a vision triage kept the 1,708 that actually depict fiber or cable routes rather than logical topology diagrams; and a stricter screen — could a cartographer produce a useful KML by tracing this image against real map data? — kept 54. Of those 54, nine now align to draft KML: three fully automated, five with a librarian reading the map and placing control points by hand, one model-assisted. The rest have their routes traced in pixel coordinates and are waiting for a person to place three or four intersections.

The tracing is ordinary image processing, and it works because the material is ordinary: a presenter draws their fiber in one saturated color over a lighter basemap. Georeferencing is the part that resisted automation longest, and the note is candid about why. A vision model asked to name control points across a whole slide drifts into plausible invention — it proposed a tidy series of numbered-street crossings, most of which were not printed on the map at all, and which were collinear, so they could not have constrained the transform even if they had been real. Asking about each quarter of the map separately, verifying every proposed point against a small crop, and pooling several rounds fixed most of that.

Two traps are recorded for anyone attempting this work. Street grids are self-similar: pure geometry matching locked confidently onto an alignment 25% off in scale, with every road landing on a road, just not the right one. And with enough junk control points, some subset will agree — a set of local exchange names that geocoded, unbounded, to random places worldwide produced a fit with innocent-looking residuals. Consistency alone is not evidence. A smaller lesson, but a real one for archives: landmark names rot. An arena named on a slide from the 2010s had been renamed by 2025 and no longer resolves. Street intersections are the durable currency.

These maps are historical documents, not engineering data. A route on a conference slide is what an operator chose to present, at a moment in time, at whatever simplification served the talk, and alignment accuracy is bounded by the slide’s own drawing accuracy long before it is bounded by any fitting. Nothing here has been field-verified and none of it should be relied on for anything operational. Each map links back to its source talk so the geometry can be read in its original context.