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USING GIS IN GEOMORPHOLICAL STUDIES. Background. Need for dealing with massive data. GIS: Visualize and analysis of spatial data. GIS can assist in carrying out geomorpholocial study in easier and more accurate manner. Objective.
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Background • Need for dealing with massive data. • GIS: • Visualize and analysis of spatial data. • GIS can assist in carrying out geomorpholocial study in easier and more accurate manner.
Objective To develop a GIS-based systematic approach for conducting a geomorphological study and its relevant analysis procedures. • Methodology: • Assessing existing manual approaches. • Identifying the main steps of building GIS for geomorphological studies. • Highlighting the main advantages of GIS-based approach compared to manual ones.
Manual approach • Data collection: • Topographic maps • Aerial photographs • A filed survey • Build a number of base maps: • Geological map • Drainage map (Network) • Contour map • Data calculation and tabulation. • Data analysis. • Producing final maps and graphs.
Definition required data Maps GIS-BasedApproach Data collection from secondary source of data Previous studies Field survey AutoCad Map digitizing Transformation of AutoCad drawing files Construct topology ArcInfo No errors Check errors Errors Correct errors Spatial data editing Map registration Data entry Building Data base ArcView Data analysis Data analysis and output Data visualization and output
Maps Geologic map Topographic map
Analysis capabilities • Inquiry functions. • Table • View (Map) • Surface analysis: • Building DEM • Creating contour map • Carrying out most morphometric analysis • Overlap functions: • Interrelationships between various factors.
DEM and Contour Map DEM Contour Map
Morphometric analysis Network Overlap Identify streams of the selected basin Watershed Select a basin Inquiry Number and length of streams 1st, 2nd, 3rd, 4th order Editing attribute table of watershed Frequency = Drainage density = (stream length/ drainage basin area) Stream bifurcation=
Manual Vs. GIS-based approach • Moreover, GIS-based approach has more advantages: • High analytical capabilities. • Producing maps and charts. • Providing database for further research and application
Conclusion • GIS is not a system for producing maps. • The analytical capabilities is the most important characteristics of GIS • The great potentials of GIS-based approach to be applied in geomorphological studies. • The efficiency of the suggested approach requires: • Capacity buildings activities • Training • Networking • More arguments on morphometric analysis