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TopoChronia is a free open source plugin for QGIS that converts plate tectonics input features into fully quantified maps of the Earth past topography (palaeotopography) and geography (palaeogeography), using the PANALESIS plate tectonic model.
TopoChronia uses a unique approach to create a synthetic topography for selected geological settings described in PANALESIS, including mid-oceanic ridges, isochrons, passive margins, active margins, cratons, hot-spots, abandoned arcs, continents, rifts, basins and other margins.
Input features (lines) are converted into an irregular grid of nodes with elevation values, from which a Digital Elevation Model (DEM) is interpolated using the QGIS Triangulated Irregular Network (TIN). The oceanic volume of this DEM is then compared to the present-day volume, in order to assess the difference of sea-level.
TopoChronia runs as a QGIS plugin. It can be used on QGIS version 3.36 or higher, and was developed with Python 3.12.3. TopoChronia requires GEOS v3.10 or higher for some vector operations, make sure to check your version of GEOS in the "About" section of QGIS.
A complete documentation including a step-by-step tutorial is available at https://topo-chronia.readthedocs.io/en/latest/#
To install the plugin:
- Manual installation:
- The zipped plugin is accessible on the releases page, under "Assets", click on "topo_chronia.zip" to start the download.
- Open QGIS → Plugins → Manage and Install Plugins → Install from .zip
- Select the downloaded .zip folder and click on "Install".
Apart from native QGIS python libraries, the plugin also requires the pandas Python package, that is oftentimes not
included with QGIS. If a message box appears to ask for manual installation, just clickon "ok". A full guide on how to install pandas inside QGIS is provided at:
https://topo-chronia.readthedocs.io/en/latest/#installation
For more information about required packages and versions, check the requirements.txt.
External libraries geopy and geographiclib are also required and already included in ext_libraries.
Once installed, the plugin should be listed under the "Plugin", and there should be three icons appearing on the QGIS toolbar as in the picture below:
Each of these icons allows to access the three main phases required by TopoChronia to process plate tectonics features from PANALESIS into palaeotopographic and palaeogeographic maps:
- Phase 0: Check Configuration
- Phase I: Create Node Grid
- Phase II: Interpolate Raster
More details about each phase are provided in the "Functionalities" section below.
For higher modularity, TopoChronia is divided into three main phases:
This first phase checks that all files required for processing are loaded in QGIS and fulfill requirements (geometry, fields, values).
TopoChronia requires the following input files from PANALESIS:
- Plate Model (PM): Lines describing the model features (see more details below).
- Plate Polygons (PP): Polygons describing the tectonic plates
- Continent-Ocean Boundary (COB): Polygons describing the boundary between continental and oceanic crust
- Geodesic Grid: Grid of points equally distant from one another.
- Accretion Rates: Table with plate velocities and accretion rates for each of the PANALESIS ages.
If all input files pass the check, this initial phase yields two outputs:
- A list of common reconstruction ages to all input files to base further processing.
- A dictionary of all input files location used later in the processing.
Should any check fail, the user will be informed about the issues. For fields that are not found, if the issue is linked to the field names, a dialog will open and allow the user to assign the correct field and change its name.
Please note that if you wish to change the input files, you need to do all checks again.
Once the checks are passed, the nodes conversion phase can start. The user can select one or more reconstruction age(s). The processing steps are the following:
- Prepare data: All PP and COB are aggregated for the reconstruction age.
- Convert features: All settings are converted from the PM (lines) into points with synthetic topographic values.
- Merge nodes: Nodes from all settings are merged into a single nodes file.
- Clean nodes: To avoid clash between different settings at the same location, nodes are cleaned.
The picture above shows an example of the nodes distribution for the present-day PANALESIS reconstruction.
The final phase consists of interpolating a raster from the clean nodes layer. We use the QGIS Triangulated Network (TIN) as it is the best open-source method to render topography and estimate oceans volumes (Franziskakis et al., submitted).
This last phase is also divided into the following steps:
- Interpolate raster: perform the initial interpolation with synthetic topographic values.
- Correct water load: calculates oceanic volume, and performs corrections using the present-day volume as a reference. Adjust sea-level based on corrections.
- Interpolate final raster: Apply sea-level correction to nodes elevation values and interpolate a final raster with the corrected values.
A complete documentation including a step-by-step tutorial is available at https://topo-chronia.readthedocs.io/en/latest/#
For more information about the PANALESIS model, please check out the following papers:
- Vérard, C., Hochard, C., Baumgartner, P. O., Stampfli, G. M., & Liu, M. (2015). 3D palaeogeographic reconstructions of the Phanerozoic versus sea-level and Sr-ratio variations. Journal of Palaeogeography, 4(1), Article 1. https://doi.org/10.3724/SP.J.1261.2015.00068
- Vérard, C. (2019). Panalesis: Towards global synthetic palaeogeographies using integration and coupling of manifold models. Geological Magazine, 156(2), Article 2. https://doi.org/10.1017/S0016756817001042
Also, see more recent presentations about the PANALESIS transition to open-source and FAIR compliance:
- Franziskakis, F. (2024, March 8). Reconstructing the Earth in Deep-Time: A New and Open Framework for the PANALESIS Model. European Geosciences Union (EGU) General Assembly 2024, Vienna, Austria. Zenodo. https://doi.org/10.5281/zenodo.13906863
- Franziskakis, F. (2024, December 17). Quantified Palaeotopographic and Palaeogeographic Global Maps for the Phanerozoic using the PANALESIS Plate Tectonic Model. 22nd Swiss Geoscience Meeting, Basel, Switzerland. Zenodo. https://doi.org/10.5281/zenodo.14505269
Automated tests can be done, once the plugin has been installed. Open the QGIS Python Console and type:
from topo_chronia.tests.test_runner import run_testFirst, you can perform a basic test to check if the plugin can be called and write in the console:
run_test("base_test")The output should be:
TopoChronia correctly installed and functions can be called.
Operating System: ...
geopy correctly installed, imported geopy.distance.geodesic, geop.distance.great_circle and geopy.point.Point
Second, a test can be done to load sample data (portion of the input data at 444 Ma)
run_test("load_sample_data")The output should be sample intput layers loaded in the Qgis Project
(Orange polygon = plate, purple polygon = continent-ocean boundary, red lines = plate model, green dots = geodesic grid)
Third, a full processing test is done to create the node grid based on the sample data.
run_test("process_sample_data")The output should be:
Processing Lines Selection...
Lines Selection: Success!
Processing Ridges...
Ridges Processing: Success!
Processing Isochrons...
Isochrons Processing: Success!
Processing Lower Subductions...
Lower Subductions Processing: Success!
Processing Abandoned Arcs...
Abandoned Arcs Processing: Success!
Processing Passive Margin Wedges...
Passive Margin Wedges Processing: Success!
Processing Continents...
Continents Processing: Success!
Processing Cratons...
Cratons Processing: Success!
Processing Other Margins...
Other Margins Processing: Success!
Processing Passive Margin Continents...
Passive Margin Continents Processing: Success!
Processing Rifts...
Rifts Processing: Success!
Processing Upper Subduction...
Upper Subducitons Processing: Success!
Processing Collisions...
Collisions Processing: Success!
Processing Hot-Spots...
Hot-Spots Processing: Success!
Merging Nodes...
Nodes Merging: Success!
Cleaning Nodes (1/2)...
Nodes vs Nodes Cleaning: Success!
Cleaning Nodes (2/2)...
Nodes inside Hot-Spots Cleaning: Success!
Adding cleaned nodes layer to map...
NB: Some functions (such as vector geometry fixing) require GEOS v3.10 or higher to work. If the function cannot be executed, some geometries will be left unchecked. In the end, you should see the nodes:
(Same symbology as above, with added new nodes in blue)
Contributions are welcome! To contribute:
- Fork the repository
- Make changes
- Submit a pull request
Or raise an issue here. For every issue, please mention the QGIS and Python versions you are using as well as your OS.
Florian Franziskakis
florian.franziskakis@unige.ch
enviroSPACE group, Institute for Environmental Sciences, University of Geneva
Christian Vérard
Earth Surface Dynamics group, Department of Earth Sciences, University of Geneva
Sébastien Castelltort
Earth Surface Dynamics group, Department of Earth Sciences, University of Geneva
Grégory Giuliani
enviroSPACE group, Institute for Environmental Sciences, University of Geneva
This plugin is licensed under the GNU General Public License, version 2 or later (GPLv2+). You can view the full license text in the LICENSE.txt.
TopoChronia my be reference using the following paper:
Franziskakis, F., Vérard, C., Castelltort, S., & Giuliani, G. (2026). TopoChronia: A QGIS plugin for the creation of fully quantified palaeogeographic maps. Journal of Open Source Software, 11(118), 8812. https://doi.org/10.21105/joss.08812
We acknowledge financial support from the Swiss National Science Foundation (SNSF) under Sinergia grant #213539: Long-term evolution of the Earth from the base of the mantle to the top of the atmosphere: Understanding the mechanisms leading to ‘greenhouse’ and ‘icehouse’ regimes.