La campagne géodésique des Pyrénées (1825-1827)
Abstract
In 1817, France decided to create a new map to replace Cassini’s 18th-century map. This required a network of geodetic points measured throughout the country. The Pyrenees geodetic campaign (1825-1827) measured a chain of triangles along the Spanish border, establishing forty-two first-order points, twenty-four of which remain in use by France’s IGN (National Geographic Institute) today.Four engineer-geographers led the campaign: Jean-Baptiste Corabœuf (party chief), Pierre Peytier, Paul-Michel Hossard, and Jacques-Prosper Testu. The work was divided into three years: 1825 for reconnaissance and the construction of the sites, 1826-1827 for measurements using Gambey theodolites. The Central Pyrenees presented considerable challenges with several summits requiring mountaineering expertise, and teams endured harsh weather conditions during extended high-altitude camps.The Pyrenees parallel is tied to the east to the Perpignan baseline created by Delambre et Méchain for their Meridian of 1792-1798 and to another baseline near Dax baseline in the west. Diplomatic complications arose when Spain refused access to its territory, forcing adjustments to the planned network.Modern analysis reveals remarkable precision: comparing 1826 coordinates with current IGN data shows an average discrepancy of only 10 centimeters for the twenty-four common points. The Perpignan baseline accuracy is evaluated by our calculations at 2 ppm.This bicentennial network demonstrates that the long-term sustainability of arrays of geodetic points, require rigorous protocols for design, materialization, conservation, and comprehensive documentation. Those lessons that remain relevant for contemporary geodetic networks serving tectonic studies requiring multi-century observations.
Related
- La campagne Nawdic sur les tempêtes hivernales
- Recherches archéologiques franco-albanaises de Dyrrachium : résultats de la campagne de 2022
- Complémentarités entre approches écologique et agronomique pour une gestion agroécologique des prairies permanentes de Midi Pyrénées
- The PIRAGUA_indicators dataset: Streamflow indices of the Pyrenees rivers (1950–2019)
- Snowmelt timing constrains green-up but not peak productivity in alpine grasslands of the western Pyrenees
BibTeX
@article{briole2026campagne,
title = {{La campagne géodésique des Pyrénées (1825-1827)}},
author = {Pierre Briole},
journal = {Revue XYZ},
year = {2026},
month = oct,
url = {https://hal.science/hal-05692023v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - La campagne géodésique des Pyrénées (1825-1827)
AU - Pierre Briole
PY - 2026
DA - 2026/10/29
JO - Revue XYZ
UR - https://hal.science/hal-05692023v1
AB - In 1817, France decided to create a new map to replace Cassini’s 18th-century map. This required a network of geodetic points measured throughout the country. The Pyrenees geodetic campaign (1825-1827) measured a chain of triangles along the Spanish border, establishing forty-two first-order points, twenty-four of which remain in use by France’s IGN (National Geographic Institute) today.Four engineer-geographers led the campaign: Jean-Baptiste Corabœuf (party chief), Pierre Peytier, Paul-Michel Hossard, and Jacques-Prosper Testu. The work was divided into three years: 1825 for reconnaissance and the construction of the sites, 1826-1827 for measurements using Gambey theodolites. The Central Pyrenees presented considerable challenges with several summits requiring mountaineering expertise, and teams endured harsh weather conditions during extended high-altitude camps.The Pyrenees parallel is tied to the east to the Perpignan baseline created by Delambre et Méchain for their Meridian of 1792-1798 and to another baseline near Dax baseline in the west. Diplomatic complications arose when Spain refused access to its territory, forcing adjustments to the planned network.Modern analysis reveals remarkable precision: comparing 1826 coordinates with current IGN data shows an average discrepancy of only 10 centimeters for the twenty-four common points. The Perpignan baseline accuracy is evaluated by our calculations at 2 ppm.This bicentennial network demonstrates that the long-term sustainability of arrays of geodetic points, require rigorous protocols for design, materialization, conservation, and comprehensive documentation. Those lessons that remain relevant for contemporary geodetic networks serving tectonic studies requiring multi-century observations.
SN - 0290-9057
SN - 1923-0907
ER -