A secção photographica ou artistica da Direcção Geral dos Trabalhos Geodesicos no dia 1 de dezembro de 1876 : noticia
A Portuguese report from 1876 by José Julio Rodrigues, issued by Lisbon's Academia Real das Sciencias for the Direcção Geral dos Trabalhos Geodésicos, describing the photographic section of the national survey office. Its pictures are rotated survey maps at 1:50,000 and 1:100,000 scales, with dense contour hatching, road and river networks, and handwritten place names in fine line, showing how photographic reduction was used to produce topographic sheets a designer could draw on for diagrammatic map forms.
