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

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Presentation on theme: "SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007"— 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 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Paolo Paron & Ronald Vargas Rojas FAO SWALIM - Nairobi

2 Previous Landform Mapping in Somalia SWALIM Landform Mapping Approach
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 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007

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

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

5 WHAT are landforms ? Scientific definition → mapping/boundaries IUSS (www.soils.org/sssagloss): A collection of related landforms; usually the land surface which the eye can comprehend in a single view 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. 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. SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 There is NO scientific standard for Landform definition/description

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. SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 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 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 From the hydrologic point of view: Helps in identifying the extent of floodplains Helps in identifying long/medium-term river dynamics

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

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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. SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 REMOTE SENSING is a key element in landform mapping → comprehensive and holistic view of a large portion of land

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

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

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

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

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

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

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

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

18 Our approach: SIHLMA Scale of final maps: 1:100,000 – 1:50,000
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. SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007

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20 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007
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 SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 3. Landform: 2 morphogenetic processes (Fluvial, “slope”, 18 subgroups

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

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Legend builder Selected polygon SWALIM RS & Environmental Change Workshop – 12th and 13th June 2007 Drop-down menu with all and only the possible codes

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

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

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

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

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

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


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