jravani · Oct 2, 2026 · Oct 2, 2026
diff --git a/ATTRIBUTIONS.md b/ATTRIBUTIONS.md
@@ -10,12 +10,13 @@ This project incorporates data and methodology from the following third-party so
 **Source:** TABULA (Typology Approach for Building Stock Energy Assessment)  
 **Author:** Institut Wohnen und Umwelt (IWU), Darmstadt, Germany  
 **Project:** Intelligent Energy Europe Programme, IEE/09/739/SI2.558245  
-**License:** Creative Commons Attribution 4.0 International (CC BY 4.0)  
+**Credit:** IEE Projects TABULA + EPISCOPE (www.episcope.eu)  
+**Terms of use:** [TABULA usage rules for third parties](https://episcope.eu/communication/download/). Use in research projects, theses and software applications is permitted on a non-exclusive basis, on condition that "IEE Projects TABULA + EPISCOPE (www.episcope.eu)" is visibly mentioned as the source. These are not an open licence such as Creative Commons, and the MIT licence of this repository does not cover the TABULA data.  
 **Link:** [building-typology.eu](https://webtool.building-typology.eu/)
 
 > Loga, T., Stein, B., Diefenbach, N., Born, R. (2016): *Deutsche Wohngebäudetypologie. Beispielhafte Maßnahmen zur Verbesserung der Energieeffizienz von typischen Wohngebäuden.* 2nd edition. Institut Wohnen und Umwelt, Darmstadt.
 
-`data/tabula-calculator-lite.xlsx` is a trimmed derivative of the original workbook above (unused sheets removed, the original `Info`/attribution sheet kept intact), published under the same CC BY 4.0 terms — see `data/README.md` for what was removed and why.
+`data/tabula-calculator-lite.xlsx` is a trimmed derivative of the original workbook above (unused sheets removed, the original `Info`/attribution sheet kept intact), distributed under the same TABULA usage rules. See `data/README.md` for what was removed and why. Anyone redistributing either workbook, or data derived from it, must carry the same credit.
 
 ---
 

diff --git a/README.md b/README.md
@@ -63,7 +63,7 @@ python -m venv .venv
 
 ## License
 
-MIT License — Copyright 2026 BigGeoData & Spatial AI, Technische Hochschule Deggendorf. See [LICENSE](LICENSE) for the full text.
+MIT License. Copyright 2026 BigGeoData & Spatial AI, Technische Hochschule Deggendorf. See [LICENSE](LICENSE) for the full text. The licence covers the code. The TABULA workbooks in `data/` are distributed under the TABULA usage rules; see [ATTRIBUTIONS.md](ATTRIBUTIONS.md).
 
 Found a security issue? See [SECURITY.md](SECURITY.md) for how to report it privately.
 
@@ -73,4 +73,4 @@ Developed in the context of the RENvolveIT research project (<https://projekte.f
 
 <img src="docs/assets/sponsors/CETP-logo.svg" alt="CETPartnership" width="144" height="72">&nbsp;&nbsp;&nbsp;<img src="docs/assets/sponsors/EN_Co-fundedbytheEU_RGB_POS.png" alt="EU" width="180" height="40">
 
-**TABULA & EPISCOPE (IEE Projects):** building-characteristic data ([episcope.eu](https://episcope.eu/iee-project/tabula/), accessed 08.07.2026)
+Building-characteristic data source: **IEE Projects TABULA + EPISCOPE (www.episcope.eu)**, used under the [TABULA usage rules](https://episcope.eu/communication/download/) (accessed 08.07.2026).
diff --git a/data/README.md b/data/README.md
@@ -10,15 +10,16 @@ This directory contains the TABULA Webtool workbook used to seed the heat demand
 | **Source** | TABULA Webtool, [building-typology.eu](https://webtool.building-typology.eu/) |
 | **Author** | Institut Wohnen und Umwelt (IWU), Darmstadt, Germany |
 | **Project** | Intelligent Energy Europe, IEE/09/739/SI2.558245 |
-| **License** | [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) |
+| **Credit** | IEE Projects TABULA + EPISCOPE (www.episcope.eu) |
+| **Terms of use** | [TABULA usage rules](https://episcope.eu/communication/download/): non-exclusive use, with the credit above visibly mentioned as the source |
 
 The workbook contains per-country building typology data (U-values, areas, infiltration rates, climate parameters) and reference heating demand values (`q_h_nd`) used to validate the calculation pipeline within ±2.5%.
 
 **Citation:**
 
 > Loga, T., Stein, B., Diefenbach, N., Born, R. (2016): *Deutsche Wohngebäudetypologie. Beispielhafte Maßnahmen zur Verbesserung der Energieeffizienz von typischen Wohngebäuden.* 2nd edition. Institut Wohnen und Umwelt, Darmstadt.
 
-This file is distributed under the same CC BY 4.0 terms as the original TABULA dataset. See [`ATTRIBUTIONS.md`](../ATTRIBUTIONS.md) for the full attribution statement.
+This file is distributed under the TABULA usage rules, not under the MIT licence of this repository. See [`ATTRIBUTIONS.md`](../ATTRIBUTIONS.md) for the full attribution statement.
 
 ## tabula-calculator-lite.xlsx
 
@@ -31,7 +32,7 @@ Sheets kept:
 
 The result is **11 MB**, down from **28 MB**. The removed sheets were roughly two-thirds of the file, including `Calc.Set.System`, which alone was larger than the sheet in use.
 
-This is a derivative of TABULA Webtool data and remains under the same **CC BY 4.0** licence as the original; see the attribution above and in [`ATTRIBUTIONS.md`](../ATTRIBUTIONS.md). `environment/ignis-db.dockerfile` bakes it into the `ignis-build-db` image. The data is static reference data, read once to seed Postgres and never modified afterwards, so shipping it inside the image rather than mounting it at runtime makes a given image tag reproducible.
+This is a derivative of TABULA Webtool data and is distributed under the same TABULA usage rules as the original; see the attribution above and in [`ATTRIBUTIONS.md`](../ATTRIBUTIONS.md). `environment/ignis-db.dockerfile` bakes it into the `ignis-build-db` image. The data is static reference data, read once to seed Postgres and never modified afterwards, so shipping it inside the image rather than mounting it at runtime makes a given image tag reproducible.
 
 ## Usage
 

diff --git a/docs/index.md b/docs/index.md
@@ -7,7 +7,7 @@ audience: developer
 
 [![CI](https://github.com/thd-spatial-ai/ignis/actions/workflows/ci.yml/badge.svg)](https://github.com/thd-spatial-ai/ignis/actions/workflows/ci.yml)&nbsp;&nbsp;&nbsp;[![MkDocs](https://github.com/thd-spatial-ai/ignis/actions/workflows/docs.yml/badge.svg)](https://thd-spatial-ai.github.io/ignis)&nbsp;&nbsp;&nbsp;[![codecov](https://codecov.io/gh/THD-Spatial-AI/ignis/graph/badge.svg?token=CTUZED1ELJ)](https://codecov.io/gh/THD-Spatial-AI/ignis)&nbsp;&nbsp;&nbsp;[![GitHub release](https://img.shields.io/github/v/release/thd-spatial-ai/ignis?include_prereleases&label=release&logo=github)](https://github.com/thd-spatial-ai/ignis/releases)
 
-Go microservice implementing the ISO 13790 annual heating energy demand calculation pipeline, validated against the [TABULA](https://episcope.eu/building-typology/tabula-webtool/) European building typology database.
+Go microservice implementing the ISO 13790 annual heating energy demand calculation pipeline, validated against the [TABULA](https://episcope.eu/building-typology/tabula-webtool/) European building typology database. Data source: IEE Projects TABULA + EPISCOPE (www.episcope.eu).
 
 ignis is designed as an internal microservice. Given a TABULA building variant code, it returns the annual heating energy demand in kWh/(m²·a) via a simple REST API.
 

diff --git a/docs/open-source-checklist.md b/docs/open-source-checklist.md
@@ -90,7 +90,7 @@ If your project uses third-party components, assets, or generated code that requ
 - [x] `ATTRIBUTIONS.md` file created in repository root
 - [x] TABULA building typology data (IWU) listed
 - [x] Source platform or author identified
-- [x] License type specified: CC BY 4.0
+- [x] Terms of use specified: TABULA usage rules, credit "IEE Projects TABULA + EPISCOPE (www.episcope.eu)"
 - [x] Links to original sources included
 - [x] Go dependencies noted