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Micromapping will kill OpenstreetMap

Posted Tue Jan 23 22:06:15 2024 Florian Lohoff

I have been with OpenstreetMap for 15 years. I started with an empty white nothing and early decided on mapping in a very systematic way like "All maxspeeds", "all building", "all traffic lights" and did that early with tools like Mapillary by first making Photos of all streets.

I also started using the data for civil engineer planning for Telecom infrastructure. For traffic simulations and other interesting purposes.

For 10 years i am running Quality Assurance for routing by calculating ~250k routes every 30 Minutes and watch for temporal changes in those routes.

So i guess i have a deep understanding of tagging schema. I think in hierarchies and dependencies of objects and their tagging.

Lately (for the past couple of years) i see people in for example Germany going into Micromapping. Every little stone, hedge, light, knob or straw needs to be mapped in extreme detail. Per se i dont see a problem in that undertaking.

The problem that now arises all over the place is that established tagging schemata are getting "abused". For whatever reason half-way usable tags are beeing re-used for micromapping for "physically similar" objects although these objects have a completely different sematic meaning.

This post was motivated by the abuse of highway=traffic_lights. Pure pedestrian crossings have been described with a highway=crossing crossing=traffic_lights for ages. Now people start to map additional highway=traffic_lights at every simple pedestrian crossing. So we went from a simple node to a node triplet with additional highway=traffic_lights.

As these 2 crossing types have completely seperate semantic properties this makes whole crossings indistinguishable from pure pedestrian crossings.

As routing profiles make use of these different semantic properties in estimating the delay of a traffic light this basically breaks these estimations, and worsens routing.

Turning on to a discussion on why people start doing that always ends in

the data consumer should fix his software

without really explaining how people are going to put a tangent to a point. Once removed information can not be brought back.

As a resume:

Micromapping by abusing existing tags breaks semantic meaning of data.

I think in the long run this "mapping for the renderer" and missing thinking in semantic meaning will "kill" Openstreetmap, or better, reduces the data usability for something else than a "pretty, colourful map".

I also think think this attitude of "somebody else must fix it" is also the best argument for the existence of Overture Maps.