TagDoc:Guidelines

This page describes the guiding principles under which the OpenStreetMap tag documentation in TagDoc is written. These topics also represent the main sections into which the tag documentation pages on TagDoc are structured.

Meaning

The main part of the documentation of the individual tags is the description of the de facto meaning of the tag in question. In other words: TagDoc here tries to describe how the tag is practically used my mappers in OpenStreetMap. Where this applies TagDoc tries to distinguish between uses of tags that are consensus within the OSM community (i.e. that are informally agreed on and adhered to broadly across culture and language barriers in the community) and specialty uses by specific parts of the community or individuals. This however is always limited to uses of the tag that actually occur, meanings of tags that are desired by parts of or the whole OSM community but that are not reflected in actual practical use of the tags are things TagDoc does not intend to cover.

This section typically ends with a concise summary of the significance of this tag within OpenStreetMap.

Primary tags

For secondary tags this section documents what primary tags the tag in question is typically used with.

Secondary tags

Many tags in OpenStreetMap are widely used in combination with other, subordinate tags that provide additional information on the feature in question. Such are listed and explained in their use in this combination in this section. Note this is primarily covering tags that are decidedly subordinate to the tag documented, not ones that have an independent meaning but happen to be used frequently in combination with the documented tag. This section can exist both for primary tags and secondary tags (to document tags subordinate to it one level further).

Consistency in use

As one main point of focus TagDoc tag description pages analyze the consistency of tag use according to the meaning described here within the OSM database. Or in other words: How diligently does the OSM community follow the definition of the tag it has itself delineated through practical use.

Value accuracy

For quantitative tags a distinct assessment can be made regarding the accuracy of the values recorded.

Competing tags

An important aspect of consistency in tag use is the existence of competing tags that are also used by mappers with the described or an semantically overlapping meaning.

Verifiability

Practical verifiability of tags has often a significant influence on the quality of the data, therefore TagDoc tries to assess how verifiable the tag is for mappers in practical use in the meaning described both on the ground and when mapping remotely.

Geometric accuracy

Apart from the semantic consistency and accuracy in use of tags an important question is how accurately the geometry the tag is applied to represents the described meaning - as far as this is verifiable.

Completeness

This section deals with how complete mapping of this feature type is in OpenStreetMap (for primary tags) or how frequently is this tagged on where it could be correctly applied (for secondary tags).

History of use

Finally it is often highly useful to know how mapping with a certain tag developed historically in OpenStreetMap and how that affects current tag use. This in particular focuses on past changes in mapping conventions (like some tags replacing other tags in use) and data imports.

Analysis maps

Here further analysis maps are shown supplementing the feature density map from the info box.

Rendering

Where applicable this section shows how the tag is visualized in OSM-Carto and the Alternative-Colors map style.