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Type: Artigo de periódico
Title: Implementation Of Programs And Routines For Conversion, Edition And Production Of Numeric Models For Gis [implementação De Programas E Rotinas Para Conversão, Edição E Produção De Mnts Para Sigs]
Author: Nanni M.R.
Comunello E.
Nanni E.L.
Abstract: The data transfer among different software is not always possible. Even so its possible, sometimes it's in the form that not satisfy the user. In the use of geographic information systems (GIS), there is the need of data exchange maintained by different systems. This exchange has, among several objectives, the reduction of creation costs of digital data with standardization and dissemination of databases. According to literature, in spite of the existence of patterns for data exchange, the development of specific solutions for the data conversion among different systems is more common, mainly when the adoption of exchange patterns can increase the complexity of the task and, consequently, its costs. In the GIS, one of the usual transfers refers to files of digital elevation models (DEM), that represent the variation of a certain characteristic associated to each point of a portion of the terrestrial surface. The most used characteristics for models are: altimetric, batimetric, temperature, and the concentration of geophysical and geochemical texts. The SGI/INPE is a georreferenced database that was developed for personal computers provides great entrance facility and manipulation of DEM, generation of regular grids, neighborhood operations, creation of clinographic, and aspects maps. The SGI joins the data in projects according to suitable approach to a geographical area and a certain projection. The information plans (Pls), or layers are incorpored in these projects, and they present a similar nature of data. The plans are established in agreement with the necessity of users. Each Pl can store a series of graphic objects that can be grouped according to themes, or pre-defined classes. The graphic attributes and the classes of those objects are stored with the space information that describes their geometry. The number of users interested in digitilizing maps has substantially increased. It was due, principally, to the growing demand, and popularity of the CAD programs (Computer Aided Design), and GIS. The transfer of DXF data from CAD systems to SGI/INPE has been a problem. When the data are imported to the system, the values of the quota are lost in the process, and the lines are imported which Z values equal zero. Therefore, when the data are imported to information plan of DEM type, the system cannot produce elevation models. Another problem presented by SGI is related with the edition of isolines. Besides other limitations, the system does not allow the occurrence of this operation in the same way when its works with arches. Tasks such as adjustment of lines, cuttins, suppression, or partial digitilization are not possible. In some cases, due to the inexperience of the operator or studied area particularities, the digitalized or imported isolines for the generation of the DEM are, some times, interrupted or superposed. In this way when plotters print them, the final art of production of planialtimetric maps is affected. Using the experience of other works the other alternative procedures and the production of support programs was tried to avoid these problems. Three programs were produced to facilitate the interfacing of DXF data to SGI and SGI to other software, and routines for isolines edition. The DXF files were imported to the SGI system, for the production of clinographic maps, according to the scheme presented in figure 1. The results were good. The developed programs allow sharing data between other systems.
Rights: fechado
Identifier DOI: 
Date Issue: 1998
Appears in Collections:Unicamp - Artigos e Outros Documentos

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