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SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 LANDFORM MAPPING FOR ENVIRONMENTAL APPLICATIONS: INTEGRATION OF VISUAL IMAGE INTERPRETATION.

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Presentation on theme: "SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 LANDFORM MAPPING FOR ENVIRONMENTAL APPLICATIONS: INTEGRATION OF VISUAL IMAGE INTERPRETATION."— Presentation transcript:

1 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 LANDFORM MAPPING FOR ENVIRONMENTAL APPLICATIONS: INTEGRATION OF VISUAL IMAGE INTERPRETATION AND DIGITAL TERRAIN ANALYSIS Paolo Paron & Ronald Vargas Rojas FAO SWALIM - Nairobi

2 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHAT are Landforms? WHY mapping Landforms? HOW to map Landforms? Previous Landform Mapping in Somalia SWALIM Landform Mapping Approach Results Further Uses of Landform Maps Conclusions

3 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHAT are landforms ? From the ground:

4 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHAT are landforms ? From a human abstraction/conceptual model:

5 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHAT are landforms ? Concise Oxford Dictionary: landform · n. a natural feature of the earth’s surface. landscape · n. 1 all the visible features of an area of land. Encyclopedia of Geomorphology (Fairbridge,1968): Landscapes may be defined as a stretch of country as seen from a particular vantage poit. The landscape is made up of rocks with its mantle of weathered material and soil, together with any vegetation cover and any streams, rivers, lakes, snow or ice that may be present. There is NO scientific standard for Landform definition/description IUSS (www.soils.org/sssagloss): A collection of related landforms; usually the land surface which the eye can comprehend in a single viewwww.soils.org/sssagloss Geopedologic approach (Zinck, 1998): a large portion of land characterized either by a repetition of similar relief-types or an association of dissimilar types. Many authors and works mentioned the landscape, however, very few defined the term. Hugget & Cheesman (2002): is the lie of the land, or the general configuraton of the land surface, including its relief and the location of its features, natural and human-made. It is also the lie of the sea floor and may be used in describing submarine relief features. Scientific definition → mapping/boundaries

6 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHY mapping landforms ? Relief/Landform/Physiography controls almost all processes, both natural and human, in our environment. Examples: insolation & climate of a specific location; soil formation; natural hazards (flooding extension, landsliding, coastal erosion, etc); agricultural practices; land use; infrastructures; etc

7 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHY mapping landforms ? From the Soil (and Land Assessment) point of view: Soils and Landforms are strictly correlated s=f(cl, o, R, p, t, …) & Catena concept From the hydrologic point of view: Helps in identifying the extent of floodplains Helps in identifying long/medium-term river dynamics

8 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 WHY mapping landforms ? Mapping landforms (and lithology) is THE base for investigation on all other natural resources and…it has an economic value.

9 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 HOW to map landforms ? Methodology Theoretical background: landform mapping theory -for land evaluation- goes back to the ’60s/’70s (IGU, USSR, CSIRO Australia, MEXE Oxford, ITC)……… ……..and it is almost unchanged so far. REMOTE SENSING is a key element in landform mapping → comprehensive and holistic view of a large portion of land

10 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 HOW to map landforms ? “Traditional” aerial photography interpretation Actual river Esondation paths Abandoned meander Meander belt

11 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 HOW to map landforms ? “Traditional” aerial photography interpretation Advantages Disadvantages Detailed Accurate (if stereo) Relief information Subjective Time consuming Very expensive Not integrated with other datasets

12 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 HOW to map landforms “Modern” image interpretation Multispectral, multiscalar, multitemporal images (aerial/space born) at very high resolution Digital Elevation Models & Derived Products Overlay/integration of different datasets into a GIS …still needs photointerpreter experience

13 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 SOMALIA physical environment

14 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 SOMALIA physical environment

15 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 SOMALIA physical environment Northern AOI: Desert to Semiarid climate Elevations from 0 to > 2000 m a.s.l. Coastal plain, Mountains, Plateau Southern AOI: Desert to Dry, Sub-Humid climate Elevations from 0 to > 1600 m a.s.l. Coastal dune system, River valleys and wide alluvial plain, Hills

16 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Previous landform maps The previous, most recent (1998) landform map for Somalia derives from FAO Africover. Realized from Printed Satellite Images (1: ). Methodology: ITC – LCCS (integrated with topo maps)

17 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Landform Mapping Methodology: Hierarchical landform legend (ITC Geopedologic & LCCS) + Morphogenetic analysis (Fluvial, Structural, etc) + Visual image interpretation (subjective and not quantitative) & Morphometric parametrization of the land surface (objective but not necessarly meaningful) = Somalia Integrated Hierarchical Landform Mapping Approach

18 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Our approach: SIHLMA Stage 1: Pre-field → data collection, study of methodology, preliminary legend formulation, data analysis, field survey preparation Stage 2: Field survey → data collection Stage 3: Post-field → field data input & analysis, finalization of the legend, integration with DTA, report writing. Scale of final maps: 1:100,000 – 1:50,000

19 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007

20 SIHLMA Legend 1. Landscape: 6 main groups (Mountain, Hilland, Piedmont, Plateau, Plain, Valley) 19 sub-groups 2. Relief: 7 morphogenetic processes (Coastal, Eolian, Fluvial, Gravitative, Lacustrine, Structural, Anthropic), 46 subgroups 3. Landform: 2 morphogenetic processes (Fluvial, “slope”, 18 subgroups

21 Examples of SIHLMA SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007

22 Legend builder Selected polygon Drop-down menu with all and only the possible codes

23 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Field forms & survey

24 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Outputs

25 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Outputs

26 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Further uses of landform maps Natural resources + Land degradation + Hydrology + Natural hazards + Etc

27 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Conclusions The application of landform maps for digital soil mapping and for land use and land degradation studies has shown promising results It is hoped that an extension of the landform mapping to the whole country will benefit from this previous experience Implementation of an easy to use methodological & practical toolbox allowing a precise mapping of landforms

28 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 T h a n k s f o r y o u r a t t e n t i o n


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