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Legend vs. classification scheme, the challenge for GLC 2000

Legend vs. classification scheme, the challenge for GLC 2000. H.-J. Stibig. GLC2000 Workshop: Legend. Main topics. legend for the GLC2000 product approach to be chosen for land cover classification how do we classify global land cover? which land cover classes should be included?

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Legend vs. classification scheme, the challenge for GLC 2000

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  1. Legend vs. classification scheme, the challenge for GLC 2000 H.-J. Stibig

  2. GLC2000 Workshop: Legend Main topics • legend for the GLC2000 product • approach to be chosen for land cover classification • how do we classify global land cover? • which land cover classes should be included? • what ‘legend’ do we finally need? • Use of the data set should not be restricted to global level: • how to achieve a homogenous classification of land cover at the global level • providing relevant information as far as possible also for the regional and the national level

  3. GLC2000 Workshop: Legend land cover information is required a) for different purposes b) at different geographical (management and planning ) levels • e.g. for • assessment of land resources • forest inventories • hydrological models • vegetation - atmosphere • interaction models • global • regional • sub-regional • local • thematic information needs can range • from few land cover classes (forest / non-forest) • to large number of classes • continuous range of values

  4. GLC2000 Workshop: Legend • Basic objective of GLC2000 project at global level • to map the distribution and the extent of main land cover classes • uniform and consistent data set • comparable across regions and countries • defined reference year: 2000 • compatibility to IGPB classes • Data set should provide a baseline • for assessment of land resources • for monitoring land cover change in a global context • input for global climate modeling • reference data for the implementation of international conventions • different information needs at global level

  5. GLC2000 Workshop: Legend aiming at a broader range of applications: • address theregional and sub-regionallevel • e.g. monitor processes: deforestation, desertification, .. • link to the national level where possible • number of large less, developed countries with outdated national databases where the GLC2000 could provide baseline information on land and vegetation cover GLC2000 should • provide land cover information to the best detail possible • allow to derive regional land cover classifications

  6. GLC2000 Workshop: Legend Example: regional needs for Africa

  7. Example: needs for arid sub-region (Africa)

  8. GLC2000 Workshop: Legend Example: (Sub-)Regional Needs Siberia

  9. GLC2000 Workshop: Legend different information impact on the definition of requirements a legend • Predefined legend • linked to defined purpose & limited value for other applications • forces the user to squeeze the vegetation types into a • predefined scheme

  10. GLC2000 Workshop: Legend • Limited number of broad global land cover classes: • limit possibilities of describing vegetation at • regional level • limit the range of possible applications • Large number of detailed regional land cover classes: • globally -> number of slightly different classes • risk of overlap if not well defined • (open forests vs. woodland, grassland vs. steppe) • difficulty of handling and interpreting a large number of • classes • risk of incompatibility of classes when grouping at global level

  11. GLC2000 Workshop: Legend • Problem of class names • a ) different regional use of class names • b ) different understanding in how to interpret specific classes • incompatibility between regions or data sets • ‘forest’ (IGBP): > 60% of tree cover • many of the Siberian forests with tree cover less than 60% would not be called ‘forest’ - does not correspond to regional understanding of forest • ‘forest’ (FAO): > 10% of tree cover • what is the information content of the class finally? • South American ‘Pampas’ • to ‘Steppe, Savannah or Grassland’?

  12. GLC2000 Workshop: Legend • Proposed : • Flexible classification system instead of a fixed legend • (FAO LCCS) • land cover types are described by adding up a series of land cover • classifiers and attributes • no predefined class names and legend • compatibility at higher level and the final legend are achieved by • grouping according to a selection of these classifiers and attributes

  13. GLC2000 Workshop: Legend

  14. GLC2000 Workshop: Legend Building a legend with ‘forest’ > 40% tree cover - ( = FAO ‘dense forest’) Forest > 40%

  15. GLC2000 Workshop: Legend Building a legend with ‘vegetation cover with woody component’ Woody vegetation

  16. GLC2000 Workshop: Legend Building a legend with class ‘impact of agriculture’ Agricultural Impact

  17. GLC2000 Workshop: Legend Advantages • classification of land cover can be done at different geographical level at • different detail, depending on the information available: • regional subclasses • adding regional species information to a global forest class • legend can be formed by grouping of significant classifiers and attributes • according to a specific purpose • improved possibilities to harmonize classifications between regions • improved compatibility to existing data sets (->monitoring capabilities) • contribution to standardizing land cover classification • Prerequisite • minimum set of common classifiers and attributes to be present • in order to build the global classes

  18. GLC2000 Workshop: Legend Implications for mapping method • Remote sensing (SPOT VEGETATION): • spectral information: signatures of land cover classes • temporal information: seasonal variation of spectral signatures • Limitations in detail of land cover classification • parameters not assessable • coarse resolution • foresee integration of ancillary information (as a standard procedure ?) • Step 1: classification (digital) of a single date or multi-temporal data set • Step 2: adding ancillary information • digital data layers • manually defined ROI

  19. GLC2000 Workshop: Legend

  20. GLC2000 Workshop: Legend Stratification Layer: Eco-floristic zone

  21. T GLC2000 Workshop: Legend GLC2000 Workshop: Legend GLC2000 Workshop: Legend ROIs- manual stratification

  22. GLC2000 Workshop: Legend Points for discussion • feedback to the approach of a flexible classification system • based on classifiers • allowing regional flexibility in class definition • do we need to define a ‘Minimum Legend’ for the global level? • if yes: which land cover classes?

  23. GLC2000 Workshop Your feedback on the LCCS tool? Do LCCS definitions meet the regional needs for land cover classification? • LCCS specific / technical: • need to specify a minimal set of classifiers for building up a global legend? • need to define additional rules to avoid ambiguous definitions? • need to require certain attribute information , e.g. such as ‘climate’? • are the classifiers of LCCS in a format in order to allow operational re-grouping? • training course on LCCS required

  24. GLC2000 Workshop • Ancillary data • how to integrate ancillary information in the classification procedure? • need to specify as standard what kind of ancillary information to be • used : • classifications on e.g. ecofloristic zones, soils… • data sets of geo-physical parameters • Methods of mapping • need to define the mapping methodology

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