# Welcome to MarcheALOmbre’s documentation!

Contents:

- Technical Documentation
  - marche_a_lombre package

## Overview

Marche à l’ombre calculates the shady and sunny portions of a given hiking trail in France, using time of departure, the calculated solar positions per trail point and terrain/surface elevation data

The plugin uses:

- IGN LiDAR HD elevation data (MNS/MNT)

- Sun position calculations based on datetime and location

## Features

- Dynamic layer retrieval from IGNs Web Map Service (https://data.geopf.fr/wms*r?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetCapabilities)

- Adjustable hiking speed and picnic break

- Reversal of trail

- Buffered calculation (calculation also 5m to the right and left of the trail to visualize shadow next to trail)

- Vector output with color-coded trail segments

- Statistics output (percentage sunny, etc.)

## Requirements

- QGIS 3.0 or later

- Internet connection (to download elevation data from IGN)

- Python dependencies (included in QGIS):

  - numpy

  - gdal

- Python dependencies (optional and not included in QGIS):

  - pvlib (If not installed, a manual solar position calculation is used)

## Installation

### From QGIS Plugin Repository

1. Open QGIS

2. Go to Plugins → Manage and Install Plugins

3. Search for “Marche à l’ombre”

4. Click Install

### Manual Installation

1. Download repository (https://github.com/yolanda225/qgis-marche-a-lombre)

2. Compress to ZIP-file

3. Open QGIS and go to Plugins → Manage and Install Plugins

4. Select Install from ZIP

## Usage

### Basic Workflow

1. Dowload a GPX hiking trail (e.g. from Visorando)

2. Load the GPX layer in QGIS

3. Open the plugin and configure parameters

4. Click Run

### Parameters

Input layer

  Vector line layer representing your hiking trail (tracks)

Departure Date and Time

  The date and time when you start your hike (Local Time): used to calculate solar position throughout the trail

Average Hiking Speed (km/h)

  Your expected hiking speed (default: 5.0 km/h)

Adjust hiking speed for slope

  Adjust your hiking speed using Tobler’s hiking function

Picnic Break Location (optional)

  Click on the map to set a break point (button to the right of the input box)

Picnic Duration (minutes) (optional)

  How long your break will last (default: 60 minutes)

Reverse Trail Direction

  Walk from finish to start instead of start to finish

Calculate with Buffer

  Calculate for center, left 5m, and right 5m of trail to visualize shadow next to trail

### Outputs

The plugin generates:

- MNS: High-resolution surface model around trail

- Low Resolution MNS: Larger surface model for long shadows

- Densified Trail Points: Color-coded points showing sun/shadow status

  - 🟡 Gold arrows = Sun

  - 🔵 Blue arrows = Shadow

- Statistics Table (CSV): Summary of time in sun vs shadow

## Coverage

Works for trails in:

- France Métropole

- Guadeloupe

- Réunion

- Support for possible future IGN surface elevation data of Overseas France is integrated

## Troubleshooting

Bad request /Failed to dowload data

  Might be an issue on the servers side, try again.

“No candidates found” error

  The trail may be outside supported regions or no data is available (France and French territories).

## License

GPL v2 or later

## Author

Yolanda Seifert

## Support

- GitHub Issues: https://github.com/yolanda225/qgis-marche-a-lombre/issues

- Repository: https://github.com/yolanda225/qgis-marche-a-lombre