Span Management

A span is a named collection of geographic coordinates (latitude/longitude pairs) that represents a segment of a high-voltage overhead line. All spans are private to the authenticated user who created them.

Creating a span

You can create a span in two ways:

From a CSV file (recommended)

Prepare a CSV file with at least two columns: lat and lon (decimal degrees, WGS 84). Additional columns are ignored. Example:
```
lat,lon
51.5074,-0.1278
51.5080,-0.1265
51.5090,-0.1250
```
Navigate to Spans → Upload.
Select your CSV file, enter a unique name, and optionally add a description.
Click Upload. The backend validates and stores up to 1000 coordinate points per span.

From JSON (API)

Send a POST /api/v1/spans/ request with a JSON body:

{
  "name": "MyLine-Section-A",
  "description": "Northern feeder between substations A and B",
  "coordinates": [
    {"lat": 51.5074, "lon": -0.1278},
    {"lat": 51.5080, "lon": -0.1265}
  ]
}

See API Reference for the full request/response schemas.

Viewing spans

The Spans page lists all spans belonging to the current user. Click a span name to open its detail view, which shows:

The span’s name and description.
An interactive map with the coordinates rendered as a polyline.
Buttons to request a forecast or delete the span.

Editing a span

From the span detail view, click Edit to update the name, description, or coordinate list. The PUT /api/v1/spans/{span_id} API endpoint accepts partial updates (only the fields you include are changed).

Deleting a span

From the span detail view, click Delete and confirm the prompt. This permanently removes the span and its coordinates from the database.

CSV format reference

Column	Required	Description
`lat`	Yes	Latitude in decimal degrees (WGS 84). Range: `–90` to `90`.
`lon`	Yes	Longitude in decimal degrees (WGS 84). Range: `–180` to `180`.

The header row must be present.
Column names are case-insensitive.
Rows with missing or non-numeric values are silently dropped.
The upload is rejected if fewer than two valid points remain after cleaning.
A maximum of 1000 points is stored per span.