Coordinate Systems

Summary

Coordinate systems control how SDX-Cloud localizes project data and links it to the correct real-world position. SDX-Cloud offers two setup paths: predefined coordinate systems and custom configurations. Review the selected systems carefully before you create the project.

Introduction

In SDX-Cloud, the coordinate system affects the absolute position and precision of the project. The correct setup depends on the project location, the required reference frame, and whether you use a predefined configuration or a custom setup with calibration files or manual EPSG codes.

Prerequisites

• You have the correct coordinate reference information for the project site, including the required EPSG codes and height system details.
• You know which target system should be used for the construction site.
• If using a calibration file, you have the .lok, .dc, .cal, or .gc3 file ready.
• If you are unsure which coordinate system to use, contact Sodex Support before you create the project.

Step-by-step instructions

1. Predefined coordinate system setup

1. Select the origin system that should be used as the global reference system for the project data.
2. Select the target system that should be used as the local Cartesian system for the construction site.
3. Confirm the EPSG code for each selected system so the configuration matches the intended reference systems.
4. Select the required vertical reference system from the available predefined height systems.
5. Wait for SDX-Cloud to validate the selected combination before you finalize the project.

Expected result: The selected source, target, and height systems form a valid configuration for the project.

2. Custom coordinate system setup

1. Use a calibration file (LOK, DC, CAL, or GC3) to localize the project. GC3 (Topcon) files are supported, and control points are parsed and displayed during validation.
2. Or enter an EPSG code manually and select the height system (ellipsoidal, geoid-based, offset, or inclined plane).
3. If the required EPSG code is not in the dropdown, enter it manually. This is expected for US state planes and other regional systems.
4. If the required geoid model is not available, contact Sodex Support or use the offset or inclined plane method.
5. If the required EPSG code is not listed, search for and select the correct code before you continue.

Expected result: The project is configured with the correct coordinate system and vertical reference setup.

3. Avoid datum-shift pitfalls

1. Compare whether a datum shift is applied in both the source and target coordinate systems.
2. If one system applies a datum shift and the other one does not, expect an offset in the transformed coordinates.
3. Review combinations such as WGS84 → ETRS89 carefully because this transformation can apply a datum shift.
4. If you want to stay in the same reference frame, combinations such as ETRS89 → ETRS89 or WGS84 → WGS84 are usually the safer choice.
5. If you are unsure which combination is correct, contact Sodex Support before creating the project.

4. Validate the setup before creating the project

1. Review the selected origin, target, and height systems one more time.
2. Make sure the selected systems match the project location and project requirements.
3. For predefined setups, resolve any validation errors before you continue.
4. For custom setups, confirm that the calibration file or EPSG code is correct and the required geoid model is available.
5. Create the project only after the configuration is verified.

Expected result: The project is created with the intended coordinate system and can be localized correctly.

Limits and notes

• The coordinate system cannot be changed after project creation.
• For predefined setups, SDX-Cloud validates the combination before project creation.
• For custom setups, validation depends on the files and codes provided.
• If a required geoid model is missing, contact Sodex Support.
• If an EPSG code is not listed, search for and select the correct one.
• If you are unsure about the correct coordinate system, contact Sodex Support before continuing.

Related articles

• Article: SDX-Cloud: Overview
• Article: Ground Control Points in SDX-Cloud
• Article: Setup Ground Control Points to enhance your project's accuracy