MAPPING CHANGES OF RIO DE JANEIRO CITY BRAZIL: MAP PROJECTIONS AND GEODETIC SYSTEMS USED

P.M.L. Menezes, M.C. Fernandes

Federal University of Rio de Janeiro, Geography Department, Rio de Janeiro, Brazil

pmenezes@acd.ufrj.br

 

The aim of this paper is to present an evolution of the mapping techniques applied to the Rio de Janeiro City (Brazil), related to the several map projections and geodetic systems associated, from the first precision mapping studies, until today.

The paper begins with the middle of 19th century, when two triangulation implantation were attempted, in order to elaborate a precise topographical map Imperial Capital. The first involved a cadastral definition of the city and the second was part of the General Commission of Brazilian Empire Map. Neither one had much success, and was just implemented a small network, without the necessary precision.

In 1890, after the proclamation of the Republic, the Municipal Government of Rio de Janeiro City, created the Commission of the Cadastral Map, which took advantage of the previous project and established a first order network, to serve and to support the proposed cadastre. This work was extended until the beginning of the 20th century, when the General Map of Brazil Commission was created. This Commission defined a poliedric projection (gnomonic), with charts of 10' x 10'. The tangent point was established at a point belonging to the network triangulation, located at Astronomical Observatory of Morro Santo Antonio, located in the center of the City.

Finally in 1922, the first photogrammetric mapping at Brazil was concluded, by the two 1: 50000 charts of the municipal district of Rio de Janeiro. The Clarke ellipsoid was used as base of the geodetic system.

In 1932, the Geographical Army Service adopted the Gauss-Krüger system, associated with the same Clarke ellipsoid. From 1942, the format of the charts was modified to the dimensions of 15 ' by 15'.

At that time the Gauss-Tardi system was adopted, associated to the Hayford ellipsoid, guided by the National Observatory. In 1957, according to UGGI recommendations, the UTM map projection system was adopted, which is still in use until today.

From that time just on some minor changes have been made, related to the used geodetic systems, such as: Córrego Alegre, SAD-69 and nowadays SIRGAS 2000.

The paper will present all of the compatible structuring undertaken to conciliate the different projective and geodetic systems and their transformations, shown by way of the transformation models proposed and applied to the maps of Rio de Janeiro City.