Guillaume-Henri Dufour is one of the most outstanding personalities of the 19th century. He was born on Sept. 15, 1787 in Constance and died on July 14, 1875 in Les Eaux-Vives (today a suburb of Geneva). When Dufour was two years old his family moved to Geneva where he went to school at the "Collège" and later on studied humanities and physics at the academy. From 1807 to 1809 he studied at the Polytechnical Institute in Paris and from 1809 to 1810 he attended the "Ecole supérieure d'application du génie" in Metz. Beginning in 1811 Dufour served in the military for the French army, mainly constructing fortifications on the island of Corfu. He quit the service in 1817 and returned to Geneva. During the same year he married Suzanne Bonneton with whom he had four daughters: Annette (1820), Louise (1823), Elisabeth (1828) und Amélie (1835).
From 1817 to 1850 Dufour was the official civil engineer for the Canton of Geneva. There are still many examples of his function in the form of suspension bridges, the reconstruction of the waterfront promenade or establishing the cantonal cadaster. Furthermore, he supported the construction of the railway line Lyon – Geneva, promoted the acquisition of the first steam boats on the Lake of Geneva, as well as advocating the introduction of gas lighting in the city of Geneva. Also in 1817, Dufour was integrated in the newly created Swiss armed forces where he took part as co-founder of the military academy in Thun. Here he held office as military instructor and teacher until 1831, among others of Louis-Napoleon Bonaparte, the future Napoleon III, with whom he shared a friendship for the rest of his life.
In 1832 he was appointed Quartermaster-General of Switzerland (Chief of staff) and was thus commissioned with organizing the defense of Switzerland in case of war, and hence also in charge of the entire Swiss fortifications. In this capacity he was to oversee the preliminary work for the Topographische Karte der Schweiz 1:100,000. The trigonometric surveys already began ten years earlier, however, progress was hindered by various circumstances, most notably the lack of financial support. In 1838 Dufour was able to hire the draftsman Johann Jakob Goll and the Polish engineer Alexandre Stryjenski on a permanent basis and set up the Bureau topographique fédéral in Carouge by Geneva – the official founding of today's Federal Office of Topography swisstopo. During the same year he supervised the publication of the Carte topographique du Canton de Genève 1:25,000 which is regarded as the model for all further cartographic works.
With respect to the baseline observations in the Grosses Moos between Walperswil and Sugiez (in 1791, 1797 and 1834), a so-called primordial triangulation was carried out across the Alps and successfully finished in 1837. The topographic surveys initiated by Dufour were conducted by the cantons beginning in 1839. These surveys led to the Topographische Karte der Schweiz 1:100,000 (mono-color copper engraving), which was printed in twenty-five sheets between 1845 (sheet XVI) and 1865 (sheet XIII). The map was designed with respect to Flamsteed's modified projection and is based on a map sheet division which is still valid for today's national maps. The old observatory in Bern is the point of origin of the Swiss national triangulation, and as the vertical reference point the height of the Chasseral – initially determinated (or: measured??) by French surveyors – was taken (or: used??). For terrain representation, Dufour used shaded hachures and rock engravings with arbitrary lighting from the northwest to enhance details. The surveying work and especially the cartographic representation reflect Dufour's education and training in France. The Dufour map won a gold medal at the Exposition Universelle in Paris in 1855. Numerous other awards at international exhibitions followed. In 1863, the highest mountain peak in Switzerland, the Höchste Spitze, was renamed Dufour Spitze, which required a correction and an immediate reprint of sheet XXIII (first edition 1862).
In the meantime Dufour also carried out different military tasks involving matters of defense and mediation, for example in Basel, Geneva and Neuchâtel. On October 21, 1847, he was appointed Commander of the federal troops by the Tagsatzung (parliament). As general he was to dissolve the so-called Sonderbund. After leading a clever and almost bloodless field campaign lasting about three weeks, the rebel cantons surrendered. He regularly pledged his troops to abide by the strict humanitarian principles. During the revolution in the Grand Duchy of Baden in 1849, and in connection to the French-Sardinian war against Austria in 1859, Dufour again took command of the Swiss Army in order to ward off any conceivable attacks on Switzerland.
In addition to his functions as engineer and officer, Dufour was politically active in Geneva as well as on the federal level. In Geneva he was elected to the representative council in 1819 where he stood in for the Liberals. On the national level he was a member of parliament as representative for the Bernese Seeland from 1848 to 1851 and for the Canton of Geneva from 1854 to 1857. From 1862 to 1866 he even represented Geneva in the upper chamber of parliament. In 1863 he was one of the five co-founders of the Comité international de secours aux militaires blessés, the subsequent International Committee of the Red Cross (ICRC) over which he presided in its first year.
Guillaume-Henri Dufour wrote the Lehrbuch der Taktik (textbook of tactics) (1842, French in 1840) as well as publications on fortifications and different military-historical studies. His activity as engineer and scientist was exceptionally diverse: among other subjects he dealt with geometry, map projections, statics in bridge construction, resistance of solid bodies, applied mechanics, surveying, hydraulics, water level measurements and gnomons.
His Topographische Karte der Schweiz 1:100,000 is internationally regarded as a pioneering achievement. Dufour's exemplary and detailed instructions allowed several cantons to use his topographic surveys and publish them as large-scaled cantonal maps.