# UTM Coordinate System

UTM Coordinates is a **projected** coordinate system. It divides the Earth into 60 zones, each 6 degrees of longitude wide.

It is not a Geodetic Coordinate system

Beacuse UTM is a projected coordinate system. It doesnâ€™t use latitude and longitude. Geodetic system means that it measures a point relative to some ellipseâ€™s center.

UTM translates the 3D curved surface of the earth into a flat 2D map.

Within each zone, locations are described using Easting and Northing values, which are linear measurements in meters.

Easting measures distance east from the central meridian of the zone. Northing measures distance north (or south, in the southern hemisphere) from the Equator.

UTM coordinates are more convenient for distance calculations and mapping over small areas since they use a flat, rectangular grid.

### How this is done in ROS2?

We use `geographic_msgs/UTMPoint`

- This message represents a point in UTM coordinates, which includes fields for the UTM zone and band, easting, northing, and altitude.
**Usage**: Itâ€™s used when you need to work with or represent UTM coordinates directly.**Message definition**:

```
string utm_zone
uint8 utm_band
float64 easting
float64 northing
float64 altitude
```