# Difference between OSM and GIS

## Meet the tags

The most striking difference is the way attributes are stored in OSM: not in a separate table, but through an open [tag system](https://wiki.openstreetmap.org/wiki/Tags), consisting of two free format text fields ('key' and a 'value') associated with each element. The OSM tag *key* identifies *"a topic, category, or type of feature*" whose value is specified in the "*value"* attribute, e.g. [amenity=drinking\_water](https://wiki.openstreetmap.org/wiki/Tag:amenity%3Ddrinking_water) to describe a point on the map, that marks a fountain with potable water.

What is fascinating is that the tagging schemes are open and determined by vague community consensus (read more on the OSM community and how they communicate [here](https://mapbox.gitbook.io/open-data-openstreetmap/details-openstreetmap/details-interacting-with-the-community)) which can yield confusing results (read up on the [power=station fiasco](https://wiki.openstreetmap.org/wiki/Tag:power%3Dstation), or [highway=cycleway](https://wiki.openstreetmap.org/wiki/Tag:highway%3Dcycleway))

## Comparing GIS shapefiles and OSM data

|                                                                 |    GIS   |  OSM |
| --------------------------------------------------------------- | :------: | :--: |
| Free data updates                                               |     ❌    |   ✅  |
| Globally unique object IDs, attribute definitions               |     ❌    |   ✅  |
| Version control through community                               |     ❌    |   ✅  |
| Combining geometries in one format (points, lines, or polygons) |     ❌    |   ✅  |
| XML data format                                                 |     ❌    |   ✅  |
| Owner controls data                                             |     ✅    |   ❌  |
| Bottom-up (crowd controlled)                                    |     ❌    |   ✅  |
| Data license                                                    | Variable | ODbL |

## GIS data for OSM or vice versa

### You have geospatial data.

👉 [Here's more info on what type of data makes sense to add to OSM and how.](https://mapbox.gitbook.io/open-data-openstreetmap/technical-specifications/technical-tracing-over-or-importing-data)

### Interested in crowdsourced OSM data?

👉 Read on [here to learn about tools to extract the data](https://mapbox.gitbook.io/open-data-openstreetmap/technical-specifications/technical-tools-for-osm) you need from the global OpenStreetMap database.
