#
Coordinate Systems and EPSG-Codes

**all services**

### Characteristic

### Short description | **Coordinate System**

A coordinate system is a system which uses one or more coordinates to uniquely determine the position of a point or other geometric element.

### Short description | **EPSG-Codes**

The EPSG Geodetic Parameter Dataset is a dataset of coordinate reference systems and coordinate transformations.

### Use

Visualizing spatial information is a basic function for the most PTV xServer Use Cases. Therefore this page explains the usage of EPSG-Codes to specify your coordinate system.

### Detailed Consideration

#### EPSG-Codes

The EPSG Geodetic Parameter Dataset is represented by a 4- to 5-digit code (e.g. EPSG:4326 = WGS84). The codes can be global, regional, national or local in application. By using EPSG-Codes there is no need for transformation formulas in the background. All codes of the EPSG Geodetic Parameter Dataset V8.6.0.0, maintained by the Geodesy Subcommittee of OGP, are supported.

You can search for EPSG-Codes and gain information about the area covered by a code at EPSG Geodetic Parameter Dataset.

#### EPSG-Codes and coordinate system

The following table shows the connection between the EPSG-Code and the referenced coordinate system.

Coordinate System | EPSG-Code | Description |
---|---|---|

World Geodetic System | EPSG:4326 | Longitude/latitude coordinates in decimal degrees [°] (WGS84). Example: X = 8.2505556, Y = 48.7627778. |

Web Mercator | EPSG:3857 | Google Web Mercator, Spherical Mercator, (WGS 84 / Pseudo-Mercator). Example: X = 918447.648154, Y= 6234705.18923. |

Proprietary PTV format | EPSG:76131 | PTV representation of coordinates according to the Mercator projection. Example: X = 917420, Y = 6227729. |

#### Usage

The used coordinate format can be specified in the RequestBase.coordinateFormat.

### Good to know

### Own coordinate inputs

Own coordinate inputs are internally rounded by xServer onto a "grid". The maximum distance of two adjacent points on this grid is 2 cm. Therefore coordinates in the response slightly differ from the entered original coordinates.

### Reuse of requests

When coordinates from the response of a first request are reused in a later second request it is important to make sure that the coordinates are taken over completely with all the decimal places in the second request. We then guarantee that xServer internally calculates with the same coordinates on both requests for the three mentioned coordinate systems above. This should also be true on all other coordinate systems, but is not verified by us.