1
Global Observation of Forest and Land Cover Dynamics
UN Land Cover Classification System
needs-concepts-implementation Martin Herold (1) & Antonio Di Gregorio (2)
(1) ESA GOFC-GOLD Land Cover Project OfficeFSU Jena, Germany
(2) FAO & UN Global Land Cover Network
Overview
• Content:1. Land cover mapping – status quo2. Harmonization and standardization3. UN Land Cover Classification System4. Implementation activities
• Purpose:Introduction of evolving initiatives (global)Invitation for scientific community to participateOpen discussion forum for European experts
GEO(SS), UNFCCC, UNCBD, MEA, …
STRATEGY
IMPLEMENTATION
GCOS Global Terrestrial Observing System
(GTOS)
IGOS Partnership
Committee on Earth
Observation Satellites (CEOS)
incl.Cal-Val
International Sponsors of GTOS: FAO, UNEP, ICSU, UNESCO, WMO
GOOSAssociates
of CEOS
REQUIREMENTS
GOFC-GOLDCol
labor
ative
Proje
cts
Technical panel
Data“producer” Science Data
“users”
Background• Land cover is the most important element for description
and study of the environment
• Land cover is the easiest detectable indicator of human interventions on the land (proxy for processes)
• Land cover is a critical parameter for (multi-purpose) environmental databases
• Land cover can be considered the key explicitkey explicit featurefeaturewhich other disciplines may use as geographical reference
• Land observations are not operational – in a weather forecasting sense
• Dealing with heterogeneity:Land surface itself, mapping standards, users of land information
• Growing RS data bases and evolving technologies
International drivers• International initiatives outline land observation requirements,
e.g. GEOSS reference plan:Land cover is important for all areas of societal benefitTerrestrial domain is least developedGEO 2006-09 work plan and Forest Community of Practice
• UNFCCC-GCOS impl. Plan tasks GTOS and GOFC-GOLD:Establish international standards for land-cover characterization Develop an in situ reference network and apply validation protocols Generate products documenting global land-cover characteristics
• Reliable and accepted land (or carbon) change estimates assume international consensus on approaches
• Ongoing/planned global mapping efforts:– GLOBCOVER, UN GLCN, FAO/FRA 2010, UNFCCC-REDD
• the derived legends too discipline specific(good detail for the some specific theme poor for others)
Each discipline producing is ownland cover data base
RangelandAgriculture
Forestry
Natural vegetation classes
Agricultural classes
Forestry classes
Mapping Tradition
Agriculture map 1a 1b 1c 1d 1e 1f 1g 1h 1i 1l 1m 2a 2b 3a 3b
Forestry map 1a 1b 1c 1d 1e 1f 1g 1h 2a 2b 3a
Derived consequences • the same geographic area mapped several time (at different scales, for different purposes, in different times, whit different type of data, whit different accuracy etc.)
Rangeland map 1a 1b 1c 1d 1e 1f 1g 1h 1i 1l 1m 2a 2b 3a 3b 3c 3d
Land cover mapping
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In the past (more than 15 years ago) not a severe constraint
Presently, and especially in the future, it is a severe limiting factor
spatial analysis (GIS capabilities) very limited
different disciplines were building up their own data set
spatial analysis (GIS capabilities) very powerful and diffuse at any levelEarth observation and land cover mapping technology evolving
exchange and/or use of environmental data between disciplines, organizationsand countries an essential step to enhance any management of natural resources
Each discipline producing is own land cover data base
Land cover mappingIt seems straightforward to produce land
cover datasets!
• World rich of data and advanced algorithms• Age of GIS and spatial analysis has vastly
enhanced the users for land cover information• National/international land mapping initiatives:
• reflect different interests, requirements and methodologies
• Current maps exist as independent datasets:• limited compatibility, validation, and no or irregular updates
• Low efficiency and applications (change, scaling)• Technology has not solved problem of
standardization
Land cover dataset heterogeneity
• Seek compatibility and comparability:For multi-temporal analysis and updatesWithin and between countriesWithin and between applications, disciplines and agenciesFrom local to global scales
• Syntactic heterogeneity:e.g. logical data models (e.g. raster/vector)
• Schematic heterogeneity:e.g. database models/spatial reference system
• Semantic heterogeneity:Naming : trees … woodland … forestCognitive (conceptualizations/categories)
Vision for integrated & operational observations
IN-SITU (+ IKONOS type)periodically (usually 1-10 yrs)
Detailed physionomyFloristics and species distributionCrop type and rotation etc.
Effort f
or frequent u
pdatehigh
Thematic detail
Spat
ial d
etai
l
high
highlow
LANDSAT/SPOT – typeinter-annual (1-5 yrs)
Vegetation physionomy
Land type/Phenology
MODIS/MERIS
(intra
-)annual
Harmonization and Standardization
Harmonization - “Bottom up process”:
• from an existing divergence to a state of comparability/compatibility
• union of similarities in existing definitions • does not necessarily eliminate all inconsistencies
Standardization - “Top down process”:
• introduces a new, common definition or standard• application of standards should eliminate all
inconsistencies
Developments for land cover harmonization • Harmonization of soil maps/legends through FAO• Originally strong push for single lc/lu legend• Too much standardization reduces application relevance• Standardizing terminology rather than categories
Consensus on criteria and thresholds
• Workshops: FAO/UNEP 1994, LUCC 2002, GOFC-GOLD 2004• Rationales:
Separation of land cover and useCommon language (LCCS)Need for case studies and researchImpact on operational lc/lu data collection
• Implementation e.g. through GOFC-GOLD/GTOS, UN Global Land Cover Network (GLCN), research networks (LUCC, GLP)
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Overview of classification systems: The USGS Land CoverClassification System
(Anderson e al. 1972/1976)
LEVEL I Mapping scale 1:250000
LEVEL IIMapping scale 1:1000000
URBAN OR BUILT UPLAND
ResdentialCommercial and service IndustrialTransportation, communication utilitiesIndustrial and commercial complexesMixed urban or built up landOther urban or built up land
Agricultural land
Cropland and pastureOrchards, grves, vineyards, nurseries, etc.Confined feeding operationsOther agriculture land
RangelandHerbaceous rangelandShrub and brush rangelandMixed rangeland
Forest landDecidous forest landEvergreen forest landMixed forest land
Water Streams and canalsLakesReservoirsBays and estuaries
Barren land Dry salts flatBeachesSandy areas other than beachesBare exposed rocksStrip mines, quarries, and gravel pitsTransitional areasMixed baren land
Tundra Shrub and brush tundraHerbaceous tundraBare ground tundraWet tundraMixed tundra
Perennial snow or ce Perennial snowfieldsGlaciers
Mixing L.C.with L.U. terms or useof others (geographic etc.)
Absence of imp. veg. physionomicparam ( Canopy cover, Leaf type)
Absence of imp. Veg. aspects:Savannas, , Woodlands
Inproper use of mixed classes
Imbalance between classes( Tundra vs other veg.) etc.Unclear classes, inproperclass names, absence of imp.L. C. classes.
Common problem of legends• Confusion between classification system and
legend • Improper thematic definitions
e.g. spectral classes resulting from interpretation process
• Mix of terminology:land use/cover terms Regional specifics names, ecology, floristics …
• Internal unbalance/inconsistency:thematic overlaps and gaps
Classification is defined as the “ordering or arrangement of ordering or arrangement of objects into groups or sets on the basis of their relationshipsobjects into groups or sets on the basis of their relationships”(Sokal, 1974). It is an abstract representation of the situation in the field using well-defined diagnostic criteria.
Difference between Classification and Legend
Abstract representation of a classification consisting of a continuum with two gradients: circles and triangles in red and white (Küchler and Zonneveld, 1988).
Concrete situation in the field in a particular area (Küchler and Zonneveld, 1988). One should note that not all possible combinations of circles and triangles in black and white here represented occur in the left side (abstract representation).
UN Land cover classification system (LCCS)
• Classification system to describe land cover features worldwide at any scale or level of detail
• High level of flexibilityflexibility with absolute level of standardizationstandardization of definitions
• Harmonized and standardized collection of land cover data
• A system that allows a dynamic creation of classes without to oblige the user to relate to a pre-defined list of names
• Comparison and correlation of land cover classes
• Endorsed by UN, GEOSS, UNFCCC, GTOS …
• Submitted to ISO, widely approved’06, some edits
Basic concept of a land cover class (the idea)the idea)
Defined geographic
area100%
10%
>50m 30m >5m1 2 3 4 ...
97 98 99 100
3347
7883
Reference Classification System
trees
closedopen
shrubsherbaceous
sparse
evergreenbroadleaved
?
?
?
LCCS method(the language)(the language)
Trees A3Closed A10
Height 14-7m B6Needeleaved D2
Evergreen E1
=A3+A10+B6+D2+E1
Legend development in LCCS code(the concept expression)(the concept expression)
End usersMapping units
Interpretation process(the map product)(the map product)
LCCS 2 Software
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Mixed unit concept in LCCS LCCS initial structure
Understanding of classifiers• Concept of Language: The problem is to find the
right combination of words to describe things = correct combination of classifiers to describe a certain land cover feature
• Users can easily refer to classifiers• Common LCCS classifiers:
– Vegetation life form (trees, shrubs, herbaceous vegetation, lichen and mosses, non-vegetated)
– Leaf type (needle-leaf, broad-leaf) and leaf longevity (deciduous, evergreen)
– Non-vegetated covers (bare soil/rock, built up, snow, ice, water)– Density of each land category in percent cover– Additional options:
• Terrestrial / aquatic or regularly flooded• Cultivated and managed / (semi-natural)• User defined attributes• Link tool
Common ground for land characterization
Existing global land cover datasets
Deciduous
ArtificialSnow & Ice
BareHerbaceous
Shrubs
Common land cover classifiers (LCCS)
TreesCover type/ life form
Evergreen
Leaf longevity
Leaf type
BroadleavedNeedle-leaved
Cultivated/managed
Cultivated and managed/(semi-)natural
Aquatic/ flooded
Terrestrial / aquatic+ regularly flooded
The future - LCCS 3
• LCCS syntax in mathematical formulization
From LCCS 2 to 3
LCCS 2 concept and software LCCS 3
mathematicalformulation PROLOG
implementation
DLL
JAVA Other????
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Harmonization mechanisms
• Harmonization resources:– Capacity building and web-based resources (LCCS)– Raise awareness and foster use of harmonized products
• Harmonization experiences for existing datasets:– Develop legend translation protocols/case studies– Translated legends: IGBP/CORINE/GLC2000/Anderson/IPCC …– Compatibility/Comparability of datasets – Synergy among land cover products
• Harmonization in future mapping products:– Impact on future projects and operational programs– Standardized legend generation (e.g. MERIS products)– Consider inconsistencies in previous maps
• Harmonization and validation are parallel efforts
Heterogeneity of forest estimates 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
Global forest observations from satellite data
0% 100%tree cover threshold
Credit: M. Hansen/University of Maryland
GLC2000 translated to IPCC
GLC2000 IPCC land use guidance for carbon/greenhouse gas inventory calc.
LCCS
Legend Translator
Har
mon
ized
map
Synergy of existing global land cover maps for carbon cycle modeling
The SYNMAP data set (life form assemblages) compiled using synergy of IGBP DIS, GLC2000, MODIS land cover, and MODIS/AVHRR VCF to provide best estimate for land cover characteristics. Leaf attributes of trees (evergreen, deciduous, needle, broad) are not shown for reasons of visibility but are defined for each class that has a tree component (Jung et al., 2006, RSE).
Trees
Trees & ShrubsTrees & Grasses
Trees & Crops
Shrubs
Shrubs & Grasses
Shrubs & Barren
Grasses
Crops
Barren
Snow & Ice
UN Global land cover network (GLCN)• Direction, focus and guidance for harmonized land cover
classification and mapping strategy
• Implementation through resources (data, mapping strategies …), coordination, and capacity building
• Developed LCCS resources and experiences
• Several regional capacity building workshops:– West Africa 10-14 Nov 2003– South-East Asia 1-6 Dec 2003– South America 15-19 Nov 2004– Southern Africa 13-17 Dec 2004– India National 15-19 Feb 2005– North Africa/Middle East 19-25 Mar 2005– RP of China National 25-29 Apr 2005– Central America 5-9 Dec 2005– Asia Pacific 4-8 Dec 2006– NIS/CIS states 2007
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Africover BurundiCongo D.R.EgyptEritreaKenyaRwandaSomaliaSudanTanzaniaUganda
Regional Program
UN Global Land Cover Network
Asiacover Cambodia
China (Yunnan)
Lao PDR
Malaysia
Myanmar
Thailand
Viet Nam
Regional Program
UN Global Land Cover Network
New Full Country Mapping - ongoing Albania
Iraq
Libyan A.J. -ong.
Moldova R.
Romania
Yemen
Oman - ong.
UN Global Land Cover Network
SADC Angola
Botswana
Lesotho
Malawi
Mozambique
Namibia
South Africa
Swaziland
Zambia
Zimbabwe
Regional Program – proposed new harmonisation project
UN Global Land Cover Network
Sahel Senegal
Gambia
Guinea
Bissau
Mauritania
Mali
Burkina
Faso
Niger
Chad
Regional Program – proposed new harmonisation project
UN Global Land Cover Network
Official Translation Afghanistan
Lebanon
New Zealand
South Africa
UN Global Land Cover Network
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Translation in Progress Burkina FasoCambodiaCameroonYunnan(China)GhanaGuineaJava (Indonesia)Iran Isl.R.Lao P'sD.R.MalaysiaMaliMongoliaMyanmarNepalNigerNigeriaSenegalThailandTogoViet Nam
UN Global Land Cover Network
Partial Country Mapping Brazil
Bulgaria
Chile
Indonesia
Madagascar
Mexico
Tunisia
UN Global Land Cover Network
Harmonization/Validation framework
Deg
ree
of c
ompa
rabi
lity
and
harm
oniz
atio
n
Updated valid./change
Validation of new products
Design based sample of reference sites
In-s
itu
glob
al
Primary validation
LCCS-based interpretation Reference database:
statistically robust, consistent, harmonized, updated, and accessible
Updated interpretations
Comparative validation
Productsynergy
Existing globalLC products
Lege
nd t
rans
latio
ns
GLOBCOVER
• Global land cover using ENVISAT/MERIS (300 m resol.)• ESA, JRC, industry consortium (Medias France…) …• Link to international initiatives and mapping programs• Built upon previous experiences (GLC2000, LCCS)• Attempts to link with CORINE program
Global MERIS mosaic
Linking GLOBCOVER and CORINE?
• Interest by both ESA and EEA• Further involvements:
GOFC-GOLD GLOBCOVER consortiumGEOVILLE info systems (DUE Innovator: Cartochange )
• Possible avenues to link global and regional land cover mapping efforts
2005 land characterizationIntegration on data/product level?
• GOFC-GOLD has provided:CORINE – LCCS legend translation and evaluationDataset comparison and assessment of inconsistencies
Translating CORINE legend• LCCS is classification system / CORINE is legend• CORINE is internally consistent (for very most part)• Translation OK, but sometimes hard to find a common
ground with a consistent land cover description• Threshold differences:
– Many CLC vegetation classes contain no cover density information– Some qualitative (“dense”)– Some quantitative (forests, urban = 30%)
• Terminology:– Land cover and use – Processes: ‘Transitional woodland-shrub’ and ‘Construction sites’– Environmental events: ‘Burnt areas’– Cultural practices: ‘Permanently irrigated land’ and ‘Pastures’
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Translating CORINE legend• Mixing of definition criteria:
– Vegetation physiognomy versus floristic terms:• Broad-leaved versus coniferous forests• Sclerophyllous vegetation
– 1st-level class ‘Agricultural areas’ contains level 2 subclasses ‘Arable land’ and ‘Permanent crops’
• Permanent crops also among ‘Arable land’ (inside of class 212 ‘Permanently irrigated land’)
• Mixed unit categories with complex land cover:– Heterogeneous agricultural areas– Moors and heathland– Transitional woodland-shrub
• Problem of some “synthetic“ internal consistency:– Extension: pastures up to 50% trees
Vision for integrated & operational observations
IN-SITU (+ IKONOS type)periodically (usually 1-10 yrs)
Detailed physionomyFloristics and species distributionCrop type and rotation etc.
Effort f
or frequent u
pdatehigh
Thematic detail
Spat
ial d
etai
l
high
highlow
LANDSAT/SPOT – typeinter-annual (1-5 yrs)
Vegetation physionomy
Land type/Phenology
MODIS/MERIS
(intra
-)annual
Translation conclusions• Translation as process of assessing inconsistencies
and compatibility• GLOBAL:
– CORINE level II shows fair amount of agreement for classes in global LC data
– Known inconsistencies• In situ - experiences from CORINE validation:
– Classes being most subjective LUCAS in situ data interpretations also highlighted in LCCS translation
– Subjectivity index:• agriculture with significant amount of natural vegetation (42.3 %)• transitional woodland, shrub (36.1 %)• complex cultivation patterns (34.0 %)
Translation conclusions
CORINE translation conclusions • Special attention should be paid to the less accurate
classes which means that there is a need for improvement of the definition of mapping rules
• Importance for the decomposition of CLC mixed classes into pure land cover classes
• Efforts in the context of GLOBCOVER
• GEO task AG-06-03 for global land cover towards “high resolution land cover change dataset”
Towards more standardized land cover observations
• Discussion/adoption of evolving standards:– e.g. common land cover “language” – LCCS
• Assessment of user requirements and development of specifications and international consensus
• Link with existing mapping programs:– National and international– Cooperation and willingness of actors – Assess interoperability and inconsistencies (legend harmonization)
• Link with in situ data and validation protocols• Possible tradeoffs:
– Between quality - application requirements – level of standardization
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Summary
• Global activities:– Evolve LCCS and related resources and products– Implementation activities
• Evolving standards in other areas:– Land cover validation (CEOS protocols)– Land Use Classification System
• Invitation to community to participate –feedback to be expected
• North American Land Cover Summit (last week)
Web resources• GTOS:
– http://www.fao.org/gtos/• GLCN and LCCS:
– http:/www.glcn-lccs.org
• GOFC-GOLD: – http://www.fao.org/gtos/gofc-gold/
• GOFC-GOLD land cover project office:– http://www.gofc-gold.uni-jena.de/
• Land cover IT newsletter:– http://www.gofc-gold.uni-jena.de/sites/letter.html