# Technical specifications

In this section we detail what GIS data is, how it differs to OpenStreetMap data and how this data can be downloaded for further analysis, converted and manipulated.

## What is GIS data?

> A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present spatial or geographic data.

([*Wikipedia*](https://en.wikipedia.org/wiki/Geographic_information_system))

GIS data represents real world objects (roads, buildings, trees, land use, borders, topographical data such as elevation...) as points, lines, and polygon references on a map with additional attributes.

The de facto GIS industry exchange format is the ESRI Shapefile, consisting of geometric shapes (either points, lines, or polygons), described as collections of coordinates, and attributes.

For detailed information on Shapefiles visit [Learn OSM](http://learnosm.org/en/osm-data/file-formats/#shapefiles).

## OpenStreetMap data model

The conceptual model used in OpenStreetMap to describe [spatial features](https://wiki.openstreetmap.org/wiki/Elements) relies on three geometric primitives: *nodes*, *lines* and *relations* to represent points in space, linear or areal features (closed lines) and relations between elements respectively.

![](/files/-LSYohC7rWa98u4KA3Ap)

Each map element in OpenStreetMap has its attributes directly attached in form of so called [`tags`](http://wiki.openstreetmap.org/wiki/Tags). Read more about the [OpenStreetMap data model](https://www.mapbox.com/mapping/osm-data-model/) and in the [next section on differences between GIS and OSM](/open-data-openstreetmap/technical-specifications/technical-difference-between-osm-and-gis.md).


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