Urban and non-urban settlements in many regions are usually located on the lands bordering shores, rivers, canals or streams. However, housing complexes, landfills, and areas for agriculture and mining are often assig...Urban and non-urban settlements in many regions are usually located on the lands bordering shores, rivers, canals or streams. However, housing complexes, landfills, and areas for agriculture and mining are often assigned to locations without sufficiently detailed hydrographic information about subsequent potential if not actual flow and flooding impacts. Yet, for sustainable community planning with emphasis on harmonizing social, economic, environmental and institutional aspects, such information is essential. This article demonstrates how this need can in part be accommodated by way of digital elevation and wet-area modelling and mapping using the upper component of the Choapa watershed in Chile as a case study. The terrain of this area has sharply incised valleys, with communities, fields and roads strung narrowly along the Choapa River and its tributaries. Above these locations along the Estero de Los Pelambres near the Chile-Argentina border are major mining and mineral refining activities. This article provides modelling and mapping details about the wet-to-moist area zonation along the upper Choapa River valleys, and addresses some of the mining-induced changes from 2000 to 2010.展开更多
Improving the accuracy of digital elevation is essential for reducing hydro-topographic derivation errors pertaining to, e.g., flow direction, basin borders, channel networks, depressions, flood forecasting, and soil ...Improving the accuracy of digital elevation is essential for reducing hydro-topographic derivation errors pertaining to, e.g., flow direction, basin borders, channel networks, depressions, flood forecasting, and soil drainage. This article demonstrates how a gain in this accuracy is improved through digital elevation model (DEM) fusion, and using LiDAR-derived elevation layers for conformance testing and validation. This demonstration is done for the Province of New Brunswick (NB, Canada), using five province-wide DEM sources (SRTM 90 m;SRTM 30 m;ASTER 30 m;CDED 22 m;NB-DEM 10 m) and a five-stage process that guides the re-projection of these DEMs while minimizing their elevational differences relative to LiDAR-captured bare-earth DEMs, through calibration and validation. This effort decreased the resulting non-LiDAR to LiDAR elevation differences by a factor of two, reduced the minimum distance conformance between the non-LiDAR and LiDAR-derived flow channels to ± 10 m at 8.5 times out of 10, and dropped the non-LiDAR wet-area percentages of false positives from 59% to 49%, and of false negatives from 14% to 7%. While these reductions are modest, they are nevertheless not only consistent with already existing hydrographic data layers informing about stream and wet-area locations, they also extend these data layers across the province by comprehensively locating previously unmapped flow channels and wet areas.展开更多
文摘Urban and non-urban settlements in many regions are usually located on the lands bordering shores, rivers, canals or streams. However, housing complexes, landfills, and areas for agriculture and mining are often assigned to locations without sufficiently detailed hydrographic information about subsequent potential if not actual flow and flooding impacts. Yet, for sustainable community planning with emphasis on harmonizing social, economic, environmental and institutional aspects, such information is essential. This article demonstrates how this need can in part be accommodated by way of digital elevation and wet-area modelling and mapping using the upper component of the Choapa watershed in Chile as a case study. The terrain of this area has sharply incised valleys, with communities, fields and roads strung narrowly along the Choapa River and its tributaries. Above these locations along the Estero de Los Pelambres near the Chile-Argentina border are major mining and mineral refining activities. This article provides modelling and mapping details about the wet-to-moist area zonation along the upper Choapa River valleys, and addresses some of the mining-induced changes from 2000 to 2010.
文摘Improving the accuracy of digital elevation is essential for reducing hydro-topographic derivation errors pertaining to, e.g., flow direction, basin borders, channel networks, depressions, flood forecasting, and soil drainage. This article demonstrates how a gain in this accuracy is improved through digital elevation model (DEM) fusion, and using LiDAR-derived elevation layers for conformance testing and validation. This demonstration is done for the Province of New Brunswick (NB, Canada), using five province-wide DEM sources (SRTM 90 m;SRTM 30 m;ASTER 30 m;CDED 22 m;NB-DEM 10 m) and a five-stage process that guides the re-projection of these DEMs while minimizing their elevational differences relative to LiDAR-captured bare-earth DEMs, through calibration and validation. This effort decreased the resulting non-LiDAR to LiDAR elevation differences by a factor of two, reduced the minimum distance conformance between the non-LiDAR and LiDAR-derived flow channels to ± 10 m at 8.5 times out of 10, and dropped the non-LiDAR wet-area percentages of false positives from 59% to 49%, and of false negatives from 14% to 7%. While these reductions are modest, they are nevertheless not only consistent with already existing hydrographic data layers informing about stream and wet-area locations, they also extend these data layers across the province by comprehensively locating previously unmapped flow channels and wet areas.
