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Tagging For The Renderer

Posted by rphyrin on 18 March 2025 in English.

There’s a saying in a certain article on the OpenStreetMap wiki that “tagging for the renderer” is equivalent to “lying to the renderer.”

Not only that, but the article also restricts the definition and meaning of “tagging for the renderer” as “the bad practice of using incorrect tags for a map feature so that they show up in the mapper’s renderer of choice. Such tagging goes against the basic good practice principles.”

I think that “tagging for the renderer” as a term should first be treated as neutral. On its own, there is no implication that “tagging for the renderer” forces us to lie to the system. Sometimes, people want to do tagging for the renderer simply because they want to place cool symbols around their area in OSM Carto.

Take me, for example.

Several months ago, I decided to download the entire openstreetmap-carto GitHub repository to analyze all of the (cool) icons contained within it and determine which tag combinations were needed to summon such icons on the OSM default map tile.

I found that the charging station icon was really cool. I loved its light blue color scheme, and its visibility on the map tile was quite good—it was already displayed at zoom level 17, on par with bank, gallery, and embassy icons.

I wanted to place this icon around my neighborhood soon. But alas, I didn’t know where any charging stations were located. So I shelved this idea for weeks and months.

Then, during a work trip to Bandung, while walking past the campus I attended as a student several years ago, I finally saw one. A charging station in the wild! It was stationed right in front of the parking area of the Labtek V building.

I was so elated—it felt like finding a legendary Pokémon in the wild! At that moment, I immediately stopped walking, opened Vespucci, and mapped the charging station.

Vespucci is nice and easy to use. Its GPS feature allows us to immediately zoom in to the current map location. Then, I simply clicked the up-and-down icon on the bottom sidebar to download the OSM data for the area, added a new node, searched for the tag preset (typing “charging” was enough to summon amenity=charging_station—no need to memorize the tag scheme at all), and it was done.

That was my first charging station mapping, purely motivated by “tagging for the renderer,” because I thought its Carto icon was really cool.

Weeks after that, I found more and more charging stations in the wild while on work trips—

All of them were fueled by my strong motivation to “tag for the renderer.”

Discussion

Comment from H@mlet on 19 March 2025 at 12:14

Well, the phrase is usually meant as “using the wrong tags to get rendered (as one wishes)”, but that’s cumbersome to use.

Of course using the right tags knowing it will be nicely rendered by your preferred renderer is great ! :-)

Comment from Lumikeiju on 19 March 2025 at 20:41

I was similarly mistaken at first; I think “Mistagging for a renderer” is more in line with the spirit of the idea that the “Mapping for the renderer” phrase actually refers to.

Comment from redd on 23 March 2025 at 12:26

Thanks! Maybe we should rename the wiki page osm.wiki/w/index.php?title=Tagging_for_the_renderer to “lying to the renderer”?

Comment from osmuser63783 on 23 March 2025 at 12:37

Precisely. It’s a confusing Wiki page trying to explain a confusing phrase.

There’s nothing wrong with wanting to make pretty maps, or with being motivated by this. But it’s common in some OSM circles, like the community forum, to accuse people of “tagging for the renderer”. When the Wiki page equates “tagging for the renderer” with “lying to the renderer”, then what the page is trying to explain is that when people use that phrase, they’re accusing someone else of knowingly entering bad data.

Comment from osmuser63783 on 23 March 2025 at 12:38

About the suggestion to rename page: the phrase that people use, for better or worse, is “tagging for the renderer”, even though they mean “lying to the renderer”. The point of the page is to explain what they actually mean.

Comment from Minh Nguyen on 23 March 2025 at 14:55

The page was briefly renamed to “Lying to the renderer” in order to more clearly limit the admonition to data hacks. But it soon got renamed back to the original title because “lying” sounded too accusatory and most people had gotten used to saying “tagging”. Imagine commenting on a new mapper’s changeset, saying they’re “lying” – not a particularly welcoming message.

That said, “Tagging for the renderer” remains a widely misunderstood phrase. The gist of the article is that we need to balance the needs of all kinds of data consumers, current and future. Essentially that means preferring semantically accurate mapping over something more presentational and shortsighted.

Comment from -karlos- on 23 March 2025 at 21:44

„Cheating for Rendering“ ? And a redirect from „Tagging…

Comment from Mateusz Konieczny on 31 March 2025 at 10:12

There’s a saying in a certain article on the OpenStreetMap wiki that “tagging for the renderer” is equivalent to “lying to the renderer.”

no, it does not

A misunderstanding comes when people say that you shouldn’t tag something “for the renderer” even though the tags being used are accurate and not misleading. For example, if a specialist map renders a particular specialist tag (e.g. the details of power plants) then using the tags the renderer understands is a perfectly reasonable thing to do

Comment from Mateusz Konieczny on 31 March 2025 at 10:16

added

Using correct tags to get something rendered is good, using tags mismatching reality to get something rendered is bad. For example, mapping industrial area as landuse=industrial so it will appear on map is fine. Mapping nature reserve as landuse=industrial so it will be noticeable on map is wrong.

in introduction in osm.wiki/w/index.php?title=Tagging_for_the_renderer&diff=2830085&oldid=2689528 if it was unclear

lets see whether it will survive (I tried rename earlier)

Comment from redd on 31 March 2025 at 12:05

Thanks Mateusz. Can you give a hint why the rename did not work? Was there already a discussion going on?

Comment from Lumikeiju on 31 March 2025 at 19:03

Do you think adding “mistagging for a renderer” to the first line is appropriate?

from:

“Tagging for the renderer”, also known as “lying to the renderer”, is the bad practice of using incorrect tags […]

to:

“Tagging for the renderer”, also known as “mistagging for a renderer” or “lying to the renderer”, is the bad practice of using incorrect tags […]

Comment from osmuser63783 on 31 March 2025 at 19:51

That’s still equating tagging for the renderer and mistagging for the renderer, which is confusing, because it makes it sound like all tagging for the renderer is mistagging for the renderer.

Here is my attempt to explain the situation a bit better:

“Tagging for the renderer” is a phrase commonly used in the OpenStreetMap community to mean specifically the bad practice of using incorrect tags (or otherwise skewing the data) for the map features, so that they show up in the mapper’s renderer of choice. Such tagging goes against the basic good practice principles.

Of course, adding correct data to the map is perfectly fine, even when it is motivated by a desire to make the map look better (e.g. more accurate) in one particular renderer. The phrase has therefore been criticised for being confusing, and it has been suggested that it would be more accurate to speak of “mistagging for the renderer” and “lying to the renderer”. However, “tagging for the renderer” is the most widely used variant.

Comment from Lumikeiju on 31 March 2025 at 20:15

That sounds good to me :)

Comment from Mateusz Konieczny on 31 March 2025 at 20:34

“Tagging for the renderer” is a phrase commonly used in the OpenStreetMap community to mean specifically the bad practice of using incorrect tags (or otherwise skewing the data) for the map features, so that they show up in the mapper’s renderer of choice. Such tagging goes against the basic good practice principles.

Of course, adding correct data to the map is perfectly fine, even when it is motivated by a desire to make the map look better (e.g. more accurate) in one particular renderer. The phrase is confusing, and it has been suggested that it would be more accurate to speak of “mistagging for the renderer” and “lying to the renderer”. However, “tagging for the renderer” is the most widely used variant.

Using correct tags to get something rendered is good, using tags mismatching reality to get something rendered is bad. For example, mapping industrial area as landuse=industrial so it will appear on map is fine. Mapping nature reserve as landuse=industrial so it will be noticeable on map is wrong.

(this is wiki so feel free to improve it)

Comment from Duja on 1 April 2025 at 09:01

Reverted, sorry. That was pain to read, inserted in an already complex sentence:

…is a phrase commonly used in the OpenStreetMap community to mean specifically…

and does not really contribute to understanding. For better or for worse, we call that “tagging for the renderer” and it is a bad practice; the current version is straightforward about it. I can agree that the phrase may be misleading, but we can’t really go back in time and change it to “mistagging” or something. Compare Counterintuitive keys and values.

As a compromise, we may prepend it with something like

In OSM jargon, “tagging for the renderer”, also known as “lying to the renderer”, is the bad practice of using incorrect tags (or otherwise skewing the data) for the map features, …

Comment from jidanni on 3 April 2025 at 05:59

I had to get this underpass off of the roof of city hall before the mayor saw it https://github.com/gravitystorm/openstreetmap-carto/issues/5050 .

Comment from Minh Nguyen on 14 April 2025 at 14:40

Lately I’ve been taking to calling it “fudging the data”. 😋 A bit less accusatory, but still gets the point across that one is playing games with the data out of expediency.

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