# Path Analysis

Path Analysis simulates shortest paths between source and destination segments. It is separate from the `Analysis` module and supports manual source/destination input or OD table input.

## Path Types

```{figure} ../_static/images/guide/4.53.png
:alt: Path analysis modes

Metric, directional, and junction path modes.
```

Metric
: Shortest path by metric length. No additional parameter is required.

Directional
: Shortest path by directional changes. Set `Angle Threshold`.

Junction
: Shortest path by junction counts. Set `Junction Degree`.

## Optional Path Attributes

```{figure} ../_static/images/guide/4.54.png
:alt: Path analysis options

Path option panel.
```

Options can compute:

- accumulated directional changes
- accumulated junction counts
- accumulated weighted attributes from selected numeric fields

Keep option parameters consistent with the selected path mode to avoid ambiguous interpretation.

## Source And Destination Input

Manual input
: Enter segment IDs in `From ID` and `TO ID`, or select segments in the map and transfer their IDs into the fields.

OD table input
: Use a CSV or TXT file with two columns. The first column is the origin segment ID, and the second column is the destination segment ID. Column names are not required.

## Results

```{figure} ../_static/images/guide/4.55.png
:alt: Path result

Manual path-analysis result.
```

Manual input returns temporary summary data and draws a `Path Analysis` layer. OD table input does not draw every path. Instead, it writes `Path count` to the network and creates a CSV with distance and path composition for each OD pair.