Overview
The Temane mapping work and the infrastructure-layer examples in the sibling workspace both point to a useful rule: transmission analysis works best when you think in segments, crossings, and adjacency, not in one undifferentiated route object.
Why it matters
- Linear infrastructure accumulates interactions across distance.
- One route can look acceptable overall while containing a handful of difficult segments.
- Segment-based review makes it easier to compare alternatives and explain them.
When to use
Use this method when:
- comparing route alternatives
- refining a preliminary transmission alignment
- screening grid interconnection corridors
- preparing field reviews for crossings and settlement adjacency
Inputs
- route centerline or provisional corridor
- roads and access layers
- water crossings and flood-prone terrain
- settlements, buildings, schools, clinics, and other receptors
- protected areas and biodiversity-priority layers
- terrain or slope context where relevant
Workflow and method
- Define the corridor and split it into review segments.
- Identify major crossings: roads, rivers, wetlands, existing utilities.
- Screen settlement and receptor adjacency.
- Review environmental overlays and habitat context.
- Tag each segment with issues, confidence, and follow-up needs.
- Compare route variants by segment profile rather than total length alone.
Example segment logic
| Segment question | Why it matters |
|---|---|
| How many major road crossings occur here? | Affects access, design complexity, and construction coordination |
| Does the segment tighten around settlements? | Signals social sensitivity and possible land-acquisition complexity |
| Are wetlands or waterways concentrated here? | Raises crossing and ecological review needs |
| Is the line tracking existing infrastructure or opening a new corridor? | Changes disturbance profile and stakeholder implications |
Live corridor context example
Tools and patterns
Useful layer families:
- transport hierarchy with surface or road class
- power lines and substations
- receptor screening layers
- hydrology and wetland context
- protected areas and KBAs
Useful outputs:
- segment tables
- crossing inventory
- constrained-length summary
- field verification map pack
Outputs
Expected outputs:
- a segmented corridor layer
- a crossings and constraints register
- map views highlighting difficult segments
- a short narrative comparing route options
Limitations
- Open settlement data may undercount small communities.
- Crossing complexity cannot be inferred from geometry alone.
- Terrain and land tenure issues may require separate inputs.
- A desktop screen cannot replace field reconnaissance.