GOFC-GOLD Efforts in Harmonization and Validation of Land Cover Datasets Chris Schmullius & Martin Herold ESA GOFC-GOLD Landcover Implementation Project Office IGOL, Sept. 2004

GOFC GOLD introduction Multifaceted international strategy to bring the Earth’s land cover under continuous operational observation Vision to share data, information and knowledge, leading to informed action and decision support Network of participants implementing coordinated research for global monitoring of terrestrial resources, global assessments and the study of global change Establishing international standards and protocols especially with respect to issues like validation

GOFC GOLD’s role A Panel of the Global Terrestrial Observing System (GTOS) A long term process of building an improved match between Observations, Data Products and User Needs Space agencies Data “producer” Science community Data “users” FAO/UNEP etc. GOFC GOLD

Implementation priorities 2 nd GOFC GOLD land cover implementation team w/s, Jena, March 2004: Harmonization of global and regional land cover products Validation of global earth observation products Adequacy and advocacy of earth observation in serving international conventions Towards operational global observations of land Support of new IGOL-theme Strengthen international cooperations (e.g. regional networks)

Why harmonization? Land mapping uses different standards national maps, application specific, spectral classes Compatibility and comparability Within and between countries Within and between applications and disciplines From local to global scales Required for successful Improvement of mapping products Validation of global datasets Foster application: land change dynamics

Dataset heterogeneity Syntactic hetero.: e.g. logical data models Schematic hetero.: e.g. spatial reference system Semantic hetero.: e.g. cognitive conceptualizations Problems for harmonizing land cover semantics: Confusion between classification/legend (mixed units) Mix of land use/cover terms Internal unbalance/inconsistency

Framing Harmonization >> Union of similarities in existing definitions Harmonization - “Bottom up process”: from an existing divergence to a state of comparability/compatibility does not necessarily eliminate all inconsistencies Standardization - “Top down process”: introduces a new, common definition or standard standards should eliminate all inconsistencies

Harmonization strategy Originally strong push for single lc/lu legend Too much standardization reduces application relevance of lc/lu maps Standardizing terminology rather than categories W/S: FAO/UNEP 1994, GOFC GOLD 2004 (Jena/Rome) Implementation strategy : Two working groups: cover and use Find common language (LCCS) Need for case studies Impact on operational lc/lu data collection

Harmonization mechanisms Harmonization resources: Web-based resources (LCCS) Raise awareness and foster use of harmonized products Harmonization experiences for existing datasets: Develop legend translation protocols/case studies Compatibility/Comparability of datasets Harmonization in future mapping products: Standardized legend generation (GLOBCOVER) Consider inconsistencies in previous maps Harmonization and Validation of land cover products

FAO – Land cover classification system (LCCS) FAO standards common in harmonization Harmonization in UNCED’s Agenda 21 (Chapter 10), for which the FAO is task manager within the UN system LCCS: Pure Land Cover classification system Not based on predefined list of names, rather set of simple elements (classifiers) High flexibility (ability to describe/classify L.C. features at any scale or level of detail) Systematic class definition and description for the user to build up its own legend Cartographic rules fully standardized and embedded system

LCCS Status and Use LCCS-2: Software completed and ready for download September 2004 Manual available September 2004, translations in French, Spanish and Arabic scheduled in the year 2005 GOFC GOLD endorses LCCS Feedback to improve LCCS Translation of legends Rome w/s)

IGBP legend translation Rome workshop translations: IGBP DIS MODIS LC MODIS Cont.Flds. CORINE GLC2000 -> already in LCCS MODIS LC LCCS Software Workshop discussions

Forest areas in global land cover maps Forest definitions: IGBP legend : percent tree cover >60% / tree height >2m GLC2000 legend : percent tree cover >15% / tree height >3m

Differences for urban areas Sources of urban land: IGBP DIS – Digital chart of the world MODIS – MODIS(2000) + DMSP (1994/95) GLC2000 – DMSP (1994/95) Shanghai Sao Paolo

tree cover threshold 0%100% Forest cover from continuous field products Credit: M. Hansen/University of Maryland

0%100% VCF can support harmonization of land cover data tree cover threshold Credit: M. Hansen/University of Maryland

Agreement between datasets Agreement = match between all three datasets (in %)

GLOBCOVER Partnership: ESA - JRC Programs: GOFC/GOLD - IGBP Users: FAO, UNEP, UN Conventions (CCD, CB) Objectives: Global Land Cover Map in 2005 by using ENVISAT MERIS data at 300m (15 bands) Schedule: Definition phase Spring 2004 Invitation To Tender July 2004 KO December 2004 First Monthly Mosaic September 2005 GLOBCOVER V1 September 2006 GLOBCOVER V2 September 2007 Validation September 2008 Implementation: One European consortium industry/companies

GLC2000 versus GLOBCOVER GLC-2000 map at 1km res.LC map from MERIS at 300m res.

Validation of land cover datasets GOFC GOLD fosters international effort to validate all existing global land cover products Consistent with “Best Practices” identified by CEOS Land Cover Validation Working Group Create „living“ dataset for future land cover products (e.g. GLOBCOVER) Use of GOFC GOLD regional networks Harmonization experiences are essential LCCS provides the framework to translate the individual in situ interpretations Frustration with lack of funding for validation