# Coordinate System

When talking about the layout of a graph, we have to agree on how coordinates of graph elements are to be stored and interpreted. For the ELK graph, this is how it works:

The coordinates of most elements are relative to their parent element. There are a few exceptions:

- Edge labels are relative to the coordinate system their edge is relative to.
- Source points, bend points, and target points of edges are relative to the edge’s containing node. Following the usual containment conventions (as implemented in `ElkGraphUtil`) results in what is displayed in the image above.

- Tool Developers
- Graph Data Structure
- Coordinate System
- Layout Options
- JSON Format
- ELK Text Format
- Using Algorithms Directly
- Using Plain Java Layout
- Using Eclipse Layout
- Connecting to ELK
- Advanced Configuration
- Layout View Support
- Dependency Injection
- Algorithm Developers
- Getting Eclipse Ready
- Creating a New Project
- ELK Metadata Language
- Automatic Builds
- Algorithm Implementation
- Structuring Algorithms
- Algorithm Debugging
- Random Graph Generation
- Unit Tests
- ELK Contributors
- Development Setup
- Development Workflow
- Installing With Oomph
- Building ELK