Elan

Elan is a QGIS decision-support plugin for integrated urban water management by nature-based solutions.

Authors:

• Gabrielle Favreau, Pascal Molle, Nicolas Forquet REVERSAAL (INRAE)

• Sophie Aubier, Jacky Volpes Oslandia

Former contributors: Larissa Marcos, Marie-Chloé Rosse, Raphaël Delhome

License: GNU General Public License v2.0 or later

Minimum QGIS version required: 3.40.0

Last documentation update: February 9, 2026

Plugin version : 2025.12.918-beta

Attention

This project is currently under development.

Content

Documentation

• Introduction
  • One tool, two issues
  • Illustrative examples
    • Centralized/decentralized question: Petite Anse (Martinique)
    • Stormwater overflows question: Écully (Rhône)
  • Structure of the tool
  • A tool that combines different research projects
• Installation
  • Prerequisite
    • On Windows
    • On Linux
    • On Mac
  • Installing plugin
  • Installing external dependencies
    • Centralized/decentralized question: pysewer and wetlandoptimizer
    • Stormwater overflows question: pysheds
  • Installing the third-party QGIS plugins
    • Centralized/decentralized question: Data Plotly
• Obtaining and preparing geographic data
  • Inputs for the Sewer network module
    • In a French context (mainland and overseas territories)
    • In an international context
  • Using the Roads and Buildings, Population and Snap on roads modules
    • Roads and Buildings module
    • Population modules : Population (uniform distribution) et Population (areametric distribution)
      • Population (uniform distribution) module
      • Population (areametric distribution) module
    • Snap on roads module
  • Inputs for the Hydraulic module
• Creating a scenario for the centralized / decentralized question
  • Step 1: Pre-designing the sanitation sewer network (Sewer network Module)
    • Prerequisite
    • Using the module
  • Results exploration (Longitudinal sewer profile module)
    • Prerequisite
    • Using the module
    • Visualization
  • Step 2: Preliminary sizing of the WWTP(s) (Processes module)
    • Prerequisite
    • Using the module
  • Step 3: Pre-selecting a treatment train for each discharge point
    • Radar plot
    • Bar plot
  • Step 4: Creation of a scenario item (Create a scenario module)
    • Prerequisite
    • Using the module
• Creating a scenario for the stormwater overflows question
• Assessing scenarios
• Comparing scenarios

Interactive flowcharts

• Global workflow centralized / decentralized question
• Data preparation centralized / decentralized question
• Creation of a scenario centralized / decentralized question

Tutorials

• Petite Anse example
  • Obtaining and preparing geographic data
    • Prerequisite: Display a base map (here OpenStreetMap)
    • Step 1: Get the Digital Elevation Model (DEM)
    • Step 2: Specify possible discharge points (WWTP)
    • Step 3: Retrieve roads and buildings - using the IGN plugin (option 1)
    • Step 3: Retrieve roads and buildings - using Elan (option 2)
    • Step 4: Distribute population among buildings and reduce polygons to their centroids
  • Create a scenario
    • Step 1: Pre-designing the sanitation sewer network (Sewer network Module)
    • Results exploration (Longitudinal sewer profile module)
    • Step 2: Preliminary sizing of the WWTP(s) (Processes module)
    • Step 3: Pre-selecting a treatment train for the discharge point
    • Step 4: Creation of a scenario item (Create a scenario module)
    • Exercise: Creating a second scenario for Petite-Anse