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ABSTRACT
This paper analyses the development of a triangulation network in the time of Napoleon I, when, due to imperial expansion, the extension of the existing triangulation network was necessary to extend Cassini's original map of France to the newly conquered territories of the French Empire. For this purpose, triangulators had to connect the already existing regional networks with the basic French network, as well as establish completely new ones in regions where they had not existed until then. Connecting various networks into a single chain was not only aimed at improving the accuracy of maps; it was also a clear reflection of a new understanding of territorial sovereignty. This paper examines which networks were established within modern-day northern Italy and maritime Croatia, and how they were mutually harmonized and interconnected, as well as what kind of repercussions this had on the development of mapping and map standardization.
Disclosure Statement
No potential conflict of interest was reported by the author(s).
Notes
1 In the period between 1791–1795, France gained the following acquisitions: the Comtat Venaissin (1791), the Duchy of Savoy (1792), the County of Nice, the County of Montbéliard, and the Principality of Salm-Salm (1793), the Austrian Netherlands, and the Prince-Bishopric of Liège (1795).
2 Austria ceded to France its holdings in Belgium and along the left bank of the Rhine River, from Basel to Andernach, including Mainz. The Cisalpine and Ligurian Republics in northern Italy were established under French influence. Formerly under Venetian rule, the Ionian islands were also handed over to France. In compensation for the loss of their possessions in Lombardy, Napoleon gave Austria the Venetian territory east of the Adige River, including Istria, Dalmatia, and the city of Venice, thus marking the end of the existence of the Republic of Venice.
3 Originally, the Kingdom consisted of the territories of the former Duchies of Milan, Mantua, and Modena, as well as of the western part of the Republic of Venice, part of the Papal States in Romagna, and the Department of Agogna, centered in Novara. Following Napoleon’s victorious campaign of 1805, which culminated in the Battle of Austerlitz/Slavkov, the subsequent Treaty of Pressburg/Bratislava (26th December 1805) required from Austria to surrender all lands it had recently acquired from the Republic of Venice (Veneto, Istria, Dalmatia) that were now to become part of the Kingdom of Italy under French rule. Moreover, Austria was forced to cede northern Tyrol to the French client state of Bavaria.
4 The Confederation of the Rhine, which first included Bavaria, Württemberg, and Frankfurt (1807), was subsequently extended to include Würzburg, Thuringia, Saxony, Westphalia, and Mecklenburg-Schwerin (1810).
5 Cassini’s triangulation of France was initially based on primary chains but was soon supplemented with secondary and tertiary triangulation. For the state of the triangulation in 1744, see Nouvelle carte qui comprend les principaux triangles qui servent de fondement à la description géométrique de la France Par Mess.rs Maraldi et Cassini de Thury, de l'Académie Royale des Sciences. Année 1744. Paris: s.n., 1744. 1 map; 57 × 63 cm. Library of Congress, Map Division, G5831.B3 1744 .M3.
6 César-François Cassini, also known as Cassini III, died in 1784, leaving his work unfinished. His son, Jean-Dominique Cassini (1748–1845), known as Cassini IV, finished the work of his father. Carte géométrique de la France César-François Cassini de Thury, Jacques-Dominique, comte de Cassini, 1:86,400. Paris: 1789. Manuscript map in 184 sheets with Paris as a prime meridian. After being out of public use since 1793, most of the map sheets were published as a new edition in 1815. For more data on the map, see Pelletier, Citation1990. The sheets of Cassini's 1784 maps are available at https://www.geoportail.gouv.fr/carte.
7 César-François Cassini de Thury, La méridienne de l’Observatoire Royal de Paris (Paris: Hippolyte-Louis Guerin & Jacques Guerin, Citation1744); Description géométrique de la terre (Paris: Citation1775); and Description géométrique de la France (J.-Ch. Desaint, Citation1784), which was completed by his son, Cassini IV.
8 It should be noted that Cassini’s triangulation-based survey that inspired surveys of other realms was not copied verbatim. In methodological sense, the measurement of the Austrian Empire (Josephine Survey) did not refer to a combination of astronomical and geodetic measurements as recommended by Cassini and later by Liesganing. In order to save time and money, the Austrian Quartiermaster Staff Engineers prioritized geodetic operations, ignoring astronomic measurements. Furthermore, the Austrian survey lacked a triangulation network through the entire territory. Instead, the most appropriate time-conserving methods were used to construct a geometric framework for each province, including drawing on older base maps and undertaking only partial triangulations (Tebel, Citation2019: 705). Last but not least, Cassini’s map was published while Josephine topographic map stayed in manuscript, as it was considered secret until mid-nineteenth century.
9 See Carte des Triangles qui ont servis à déterminer la Position de plusieurs Lieux aux environs de Vienne : en supposant la distance de Vienne à Kalenberg (1761). Österreichische Nationalbibliothek (ÖNB), Kartensammlung, C.11.2.
10 The Cassini map would be highly utilized by the new French authorities and used as a base for a number of subsequent state maps. One of the most important examples is the Atlas national de la France (1790–1811), prepared by Pierre Grégoire Chanlaire based on updated and corrected Cassini's maps.
11 Carte des provinces de France traversées par la Méridienne de Paris 1:285,000 environ. Manuscript map in eight sheets; 66.5 × 50 cm each. Bibliothèque nationale de France (BNF), Cartes et plans FRBNF11979394.
12 This claim of scientific superiority was affirmed in the Mémorial topographique et militaire, which began to appear in 1802, when the Topographical Commission was called upon to discuss the start of construction of the future map of France at 1:80,000. (Dépôt de la guerre, 1802–1803).
13 Réseau de triangulation de l'Italie du Nord, depuis Nice, Embrun et Briançon jusqu'à Vérone et Rimini. 1:1,650,000 env / [Par] Barbié du Bocage. [S.l.] : [s.n.], 8bre 1781. Manuscript map; 59×50 cm. Bibliothèque nationale de France (BNF), département Cartes et plans, GE D-17272.
14 Nuova carta geografica dello Stato Ecclesiastico delineata dal P. Cristoforo Maire, d.a. C.a. di Gesù sulle comuni Osservazioni sue e del P. Ruggiero Giuseppe Boscovich della medesima Compagnia Maire, Christopher e Boscovich, Ruggiero. 1:375,000 Rome nella Calcografia della R.C.A. 1755.
15 Following the victorious campaign of Napoleon Bonaparte in northern Italy in 1796, the Habsburg Monarchy ceded the Duchy of Milan to the French Republic under the Treaty of Campo Formio in 1797. However, by 1796, in the territories of the Duchy of Milan, the French established, as a vassal state, the Transpadana Republic, which merged with the Cispadana Republic in 1797 to form the Cisalpine Republic, of which Milan became the capital.
16 Carta topografica del Milanese e del Mantovano basata sulle misure effettuate dagli astronomi di Brera fra il 1788 e il 1791, 10 sheets. IGM, sign. ID-1-22.
17 Oriani argued that the map of Lombardy and triangulation network he developed could easily be connected with Cassini’s map of France (Combi, Citation1930).
18 La Gran Carta del Padovano di G.A. Rizzi Zannoni della reale Società’ delle Scienze e Belle-Lettere di Gottinga 1:20,000. Map in 12 sheets, IGM, sign. Bianconi n. 136. Only four sheets were published by 1781.
19 Only a reduction at 1:234,000 was published in Vienna in 1806. It was titled Il ducato di Venezia astronomicamente e trigonometricamente (Rossi, Citation2005).
20 Carte de la partie de la Vénétie comprise entre la partie de la République cisalpine située sur la rive gauche du Pô disegnata nel 1 :86,400, 1801, Vincennes, Service historique de la Défense M 13 B IV 102.
21 Carte générale de la République italienne entre l'Adige et l'Adda. Vincennes, Service historique de la Défense GR 3 M 375-GR 3 M 377. Printed edition published in 1803: Carte de la république Italienne, constituée par la consulta à Lyon, le pluviôse an X (26 janvier 1802), divisée en 12 départements, avec la république ligurienne et toutes les parties adjacentes par C.-F. Delamarche, (Paris). [s.n.], 1803. Map in colour; 100×64 cm. BNF, département Cartes et plans, GE C-1912.
22 Zach's map was a base for the Carta topografica del Regno Lombardo-Veneto construita sopra misure astronomico-trigonometriche ed incisa a Milano dell’ Istituto Geografico Militare dell’s I.R. Stato Maggiore Generale Austriaco, 1833. Scale 1:84,600 (Rossi, Citation2007a: 409–430).
23 Canevas trigonometrique de Fiume a Turin et du Mont du Chat a L’Ocean J. Brignon Ing. de l'Etat M.r Général. S.l, c. 1811. Manuscript in colour; 82×49 cm. IGM: Florence, B0008487.
24 Established under an Austrian imperial decree by which the Habsburg Empire, starting on 1st December 1786, adopted the ‘transalpine time’, or the ‘French time’, which started the new day with the Solar noon. As Austria was ruling Lombardy at the time, astronomers of the Brera Astronomical Observatory were given the task of building a meridian line inside Milan cathedral. The meridian line is still visible on the floor of the cathedral, crossing the width of the church very close to the main entrance: it is a brass band inlaid in the floor and oriented from the south to north. At the northern end, the line continues on the wall for about 3 metres (9.84 ft), because the floor was not long enough. A hole in the roof near the south wall, at 24 metres (78.7ft) in height, allows the sunlight to come in and illuminate the brass line.
25 Carte topographique d'une partie du Piémont, entre Mondovì et Savone, levée de 1804 à 1807, Vincennes, Service historique de la Défense L.III.433; Carte Topographique de la portion des états ex Vénitiens comprise entre Piave et Isonzo. Scale 1:100,000, 1809, Vincennes, Service historique de la Défense M 13 B IV 107; Carte topographique de la portion des états ex-vénitiens comprise entre la Piave et l’Adige. 1808–1811. Scale 1:100,000, Vincennes, Service historique de la Défense M 13 B IV 108.
26 The works of French and Italian engineers in the Venetian territories gave rise to the Carte topographique de la portion des états ex-vénitiens comprise entre la Piave et l'Isonzo; and to the Carte topographique de la portion des états ex-vénitiens comprise entre la Piave et l'Adige, compiled between 1808 and 1811 under direction of General Brossier, head of the Topographical Office of Italy. Topographical surveys were conducted directly at 1:100,000, starting from the coasts. The engineers relied on the reduction of the map of the Duchy of Venice by Baron Anton von Zach, published in 1806 at a reduced scale of 1:236,000 (Frasca, Citation2020: 105–107).
27 From around the mid-eighteenth century, measurements by French cartographers reached Switzerland in several waves. The last wave between 1803 and 1813, under the rule of Napoleon, was particularly significant. In 1804, a 19-kilometre stretch was measured near Ensisheim, between Sausheim and Oberhergheim, as a baseline for the French triangulation network (Ricenbacher, Citation2011: 313).
28 Carte von Istrien aufgenommen vom k.k. Generalquartiermeisterstab in August 1797. Scale 1:57,600. Manuscript map in 7 sheets. War Archive in Vienna, Map Collection, B.IX.a.331.
29 Original Aufnahme Karte von Istrien, 13 sheets, 1:28,000. War Archive in Vienna, Map Collection, B.IX.a.333.
30 Besides topographic mapping, Napoleon ordered a hydrographic survey of the Adriatic, which was conducted by the French hydrographer François Beautemps-Beaupré in 1806–1809 (Altić, Citation2012: 17–24).
31 In contrast to Istria, which was covered by the triangulation, the Austrian General Staff did not manage to develop a triangulation network in Dalmatia, or conduct a detailed topographic survey in the period of 1797–1805.
32 There is an extensive note about the source maps that were used as a base: a map of Dalmatia by Captain Francesco Zavoreo at a scale of 1:140,000 (1797), the old Venetian land register (the mid-18th century), a map of the Zadar, Ugljan, and Pašman regions, 1:50,000 (1806), maps of the Zrmanja, Krka, Cetina and Neretva rivers, maps of Brazza (Brač), Lesina (Hvar) and Solta (Šolta) islands, an 1:115,200 Austrian topographic map of the Republic of Ragusa (1804), an 1:20,000 map of the surroundings of Dubrovnik (1806), a map of Albania at a scale of 1:80,000 and a map of the surroundings of Budva, made at a scale of 1:20,000.
33 Carte militaire et marine de la Dalmatie comprenant la Dalmatie Ex-Venetienne, la République de Raguse, les Bouches de Cattaro et les iles adjacentes. Reconnoisance militaire execute en 1806 par les Ingénieurs-Geographes français et italiens, 1:80,000, 48 gez. Blatt. 1806–1807. War Archive in Vienna, Map Collection, B.IX.a.454. Detailed memoirs testify to the reconnaissance of Dalmatia (Memoire a joindre a la reconnaissance militaire de la Dalmatie. Par Lassaret, ing. geog., 1806. War archive in Vienna, Map Collection, K.VII.i.18.
34 It was used as source for a printed map at a reduced scale: Carta dell Province Illiriche co'loro diversi stabilimenti e con una parte degli Stati limitrofi. Compilata per ordine Superiore nel Deposito della guerra del Regno d'Italia. 1:500,000. 1813. Map in seven sheets. B.IX.a.49.
35 The staff for the section of Istria consisted of Rousseau, Coraboeuf, Cicille, Pasquier, Lerouge, Tugot, Prato, Denayer, Chauvet, Benedetti, Castellino, Véron, Clement, Sion and Martel.
36 Its triangles, 400 in number, started at Sermione, on Lake Garda, passed through Solferino, Mantua, and Verona, followed the Adige, and then the canal and the Po River to its mouth. Then they took the coast of the Adriatic as far as Zadar, extending the triangulation network over Austrian Istria and the Quarnaro, and then to the coasts of Croatia and Fiume. They returned along the border of Tyrol and Monte Baldo as far as Sermione. The Depot allocated to this operation a sum of 15,000 francs (Berthaut, Citation1902: II, 373–377).
37 Carte topographique des Iles du Quarnero et de la Dalmatie entre Fiume et Zara. Assujettie aux Observations Geodesiques et levee Geometriquement par les ingénieurs géographes français et italiens. 1:50,000, 1811. B.IX.a.484-1.
38 Napoleon did not stop at topographic maps; he pursued further policies of territorialization and rationalization of his rule, such as the 1804 land property survey, in order to implement a uniform land tax. Cadastral mapping was also triangulation-based.
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Notes on contributors
Mirela Altić
Mirela Altić is Chief Research Fellow at the Institute of Social Sciences and Full Professor in the Department of History, University of Zagreb, where she has been teaching history students how to use maps as a historical resource for over 20 years. She specializes in the social history of maps, cross-cultural knowledge exchange and early modern encounter. She is the author of 22 books, numerous scholarly papers and a contributor to The History of Cartography Project. Besides her interest in Central European map history, over the last decade she has published extensively on Jesuit cartography and missionary contribution to the history of mapmaking and exploration in general. Her latest book, Encounters in the New World: Jesuit Cartography of the Americas was published by The University of Chicago Press in July 2022. Currently, she is Vice Chair of the ICA Commission on the History of Cartography, immediate past President of the Society for the History of Discoveries, and a Trustee of the International Society for the History of the Map.