منهجية خرائطية مقترحة لاستخراج شبكات مجاري مائية من نماذج الارتفاع الرقمية

Abstract EN

GIS and other spatial systems users are commonly have to perform numerous experiments to extract proper drainage network maps from digital elevation models (DEMs).

although this mechanism may be sufficient for the desired goal, these produced maps are not necessarily appropriate from a purely cartographic perspective.

that is, to produce a cartographically acceptable map, there must be an agreement between the DEM's characteristics and the map scale.

in the absence of this requirement, as being a cartographic standard, the drainage network may be either too detailed or too generalized when represented at a specific map scale.

as such, this study mainly focuses on extracting drainage networks from DEMs in adherence with map scale requirements.

a three-stage methodology was followed: data preparation, examining relevant cartographic criterions and /or standards regarding drainage networks representation, and finally applying an empirical proposed criterion on test DEMs through calibrating the flow accumulation threshold values to extract the drainage networks maps.

based on the second and the third stages results, the study found that the shortest stream was an appropriate criterion, with the value of (0.5 cm) on the map at a given scale as being the most appropriate, as the output networks appeared inconsistency and agreement with different map scales.

the study recommends usage of this value as a preliminary value.

however, in order to provide a widely accepted value, further experiments on different DEMs at different resolutions and for different topographic details are needed.