5.A.ix. Maps for Part of Brazil

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Primary Developer:		Instituto Brasiliero de Geografia e Estatistica
Title:		Maps for the International Map of the World on the Millionth Scale
Publication Date:		Various, 1970s and 1980s.
Bibliographic Citation:		Instituto Brasiliero de Geografia e Estatistica (IBGE), various dates. Carta Internacional do Mundo, ao Milionesimo. Instituto Brasiliero de Geografia e Estatistica, Rio de Janeiro, Brazil. (Physical, including topographic, maps of the world on a scale of 1:1,000,000; sheets covering Brazil.)
Post-processing:		Geographical Survey Institute (GSI, Japan), and U.S. Geological Survey (USGS) for GTOPO30.
Bibliographic Citation for Post-processed DEM:	*	IBGE, GSI, and USGS, 1997. 30"-gridded DEMs from IBGE Maps. USGS, EROS Data Center, Sioux Falls, South Dakota.
Source/Lineage Category:		16

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* Primary reference citation for this source

The International Map of the World (IMW) on the Millionth Scale project was created in 1913, when a number of national and other cartographic agencies joined to form the Central Bureau of the IMW. In 1953, IMW activities were transferred to the Secretariat of the United Nations (UNO, 1973).

The IMW project sets standards for presentation of such maps, to increase uniformity of content and presentation. Actual maps are produced by many public (and a few private) organizations. The maps used in this instance were produced by Instituto Brasiliero de Geografia e Estatistica (IBGE), the Brazilian Institute of Geography and Statistics, which has a program for 10-yearly updates to maps in this series. This forms Brazil's 1:1,000,000 topographic map series, designed to be compatible with IMW standards.

Paper maps from this series were adapted for digitizing, then digitized by the Geographical Survey Institute of Japan to provide source data for the Amazon basin and adjacent areas. The maps used for this project had a 100-meter contour interval. USGS used ANUDEM-based contour-to-grid techniques to create DEMs from these digitized map areas. That procedure is described in Section 5.A.vii.

Cell-center registration; contour-to-grid value computed. Graphic describing georeferencing and sampling for IMV map conversion.

Plate 28. Click on the image to view larger size.

Plate 28 shows sharp spikes and broader peaks occurring at 100m increments below 1000m. There is also a separate spike at 1200m, spikes at 500m increments to 3000m, and at 1000m increments above 3000m, suggesting these are contour values in the original source maps. The histogram shows a proportionately large amount of coverage around 4000m elevation.