Avaliação da acurácia do mapeamento de rios de primeira ordem em cartas topográficas no Sudoeste do Paraná

Abstract

The drainage network mapping presents methodological limitations that restrict its use in environmental studies, compromising the work based on it. In this way, the work sought to assessment the mapping accuracy of the first-order rivers on topographic maps of Francisco Beltrão, of the Santana River, of Marmeleiro and of Renascença, both in the scale 1:25.000 and located in the southwest state of Paraná (SO/PR). For this, the presence and type of flow of 80 first-order rivers were verified in the field during the dry season and compared with the records on topographic maps. For completeness accuracy, only errors of omission were verified: of the 40 permanent rivers evaluated, only 2 (5%) that had an extension greater than 250 meters were not mapped and of the 40 temporary rivers, the omission of rivers greater than 250 meters rose to 6 (15%). In this case, it demonstrates that the techniques used in mapping first-order rivers were more effective for permanent rivers. Regarding the thematic accuracy, all 21 rivers mapped as temporary (52.5%) were correctly assigned the flow typology and, of the 36 rivers mapped and identified in the field as permanent (90%), only 1 river had its own correctly identified flow. An overall accuracy of 46.25% was verified and that the problems reported in the cartographic bases used by several authors also occurred in the topographic maps studied. The research results serve as a warning for future work to carry out their validation before use, regardless of the work scale.