The MODIS Land Cover Product

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The MODIS Land Cover Product

• MODIS Land Cover Team
• Boston University

GLC 2000 FIRST RESULTS WORKSHOP JRC Ispra,
18-22 March 2002
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Terra Launch on December 18,1999
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MODIS Land Bands
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MODIS Land Cover Product

• Objective
• Provide a simple land-cover categorization for
  biophysical parameterization for GCM, hydrologic,
  and carbon cycling models

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MODIS Land Cover Product Features

• Categorizes land cover according to life-form,
  cover and height of dominant vegetation type
  following IGBP-DIS scheme
• Uses data from spectral and temporal domains
• Relies on advanced classifier technologyi.e.,
  decision treesin a supervised classification
  mode
• Network of global test sites used for algorithm
  calibration and validation
• At-launch 1-km database derived from AVHRR
  heritage
• Level 3, 1-km spatial resolution, 96-day product
  Climate Modelers Grid (1/4) product also
  available

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Recent Global Land Cover Products

• Beta Product, released April 15, 2001
• Based on 2 16-day periods of Normalized
  BRDF-Adjusted Reflectance (NBARs)
• Provisional Product 2001001, released June 15,
  2001
• Based on 9 16-day periods of NBARs within July
  11 January 15, 2001
• Uses prior probabilities to help separate
  agriculture and natural vegetation
• Includes IGBP classification, secondary classes,
  confidence measures
• Draws from at-launch product when only 02 views
  are available or when classification confidence
  is less than 40

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Recent Global Land Cover Products, Cont.

• Validated Product
• Due 15 April 2002
• Based on MODIS data from 2001
• Includes 4 sets of labels, per-pixel confidence
  measures, second choices

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IGBP Land Cover Units (17)

• Natural Vegetation (11)
• Evergreen Needleleaf Forests
• Evergreen Broadleaf Forests
• Deciduous Needleleaf Forests
• Deciduous Broadleaf Forests
• Mixed Forests
• Closed Shrublands
• Open Shrublands
• Woody Savannas
• Savannas
• Grasslands
• Permanent Wetlands

• Developed and Mosaic Lands (3)
• Croplands
• Urban and Built-Up Lands
• Cropland/Natural Vegetation Mosaics
• Nonvegetated Lands (3)
• Snow and Ice
• Barren
• Water Bodies

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The Land Cover Input Database

• Surface Reflectance
• Nadir-adjusted surface reflectance, 7 land bands
• Vegetation Index
• MODIS Vegetation Index, maximum value composite
• Spatial Texture from 250-m Band 2
• Standard deviation-to-mean ratio in Band 2
  (near-infrared), maximum value composite in
  32-day period
• To be added later

• Snow Cover
• MODIS Snow Cover Product, number of days with
  snow cover
• Land Surface Temperature
• MODIS Land Surface Temperature, maximum value
  composite
• Directional Information
• Bidirectional reflectance model choices from BRDF
  product
• Ancillary Data
• DEM, Land/Water mask

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Global Composite Map of Nadir BRDF-Adjusted
Reflectance (NBAR) April 722 2001
no data
True color, MODIS Bands 2, 4, 3
10 km resolution, Hammer-Aitoff
projection, produced by MODIS BRDF/Albedo Team
MODLAND/Strahler et al.
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MODIS Nadir BRDF-Adjusted Reflectance
May 25June 9 2001 False Color Image NIRRedGreen
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NBAR Time Trajectories
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MODIS 500 m Vegetation Indices
(September 30 October 15, 2000
NDVI
MOD13A1 16 day Composite
EVI
MODLAND/Huete et al
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Test Sites

• IGBP-DIS Core/Confidence Sites
• Random stratified sampling of classes on 1992-93
  IGBP Global Land Cover Product
• 425 sites identified 413 SPOT and TM scenes
  acquired 91 migrated to WWW by BU
• BU STEP Database
• 2614 training sites from 645 TM scenes (6/6/00)
• About 1000 training sites in current use for
  supervised classification

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DISCover Core Validation Sites
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Supplemental BU Training Sites
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STEP Database

• STEP
• System for Terrestrial Ecosystem Parameterization
• Key STEP Parameters
• Life form, height, cover fraction, of layers
• Leaf type, phenology, periodicity, physiognomy of
  dominants in layers
• Elevation, moisture regime, perturbation
• Classifications IGBP, BU, EDC SLCRs
• Simple description of site and type (words)
• STEP Flexibility
• Allows application of many different land cover
  labeling schemes by inference of label from
  parameters in database

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MODLand Support Products

• Six Biomes for LAI / FPAR Algorithm
• Used by Ranga Mynenis radiative transfer model
  in retrieving LAI and FPAR
• Six Biomes for Net Primary Productivity (NPP)
• Used by Steve Runnings Biome-BGC model in making
  the MODIS NPP product
• Fourteen ClassesUniversity of Maryland Legend
• We also provide a 14-class product using the
  University of Maryland scheme
• Preferred by some modelers

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Provisional Land Cover Product June 01
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Northeast Provisional Land Cover Product, Jul
00Jan 01
Evergreen Needleleaf Forest
Mixed Forest
Agriculture/Natural Vegetation Mosaic
Agriculture
Urban
Deciduous Broadleaf Forest
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Second Most-Likely Class
Classification Confidence Map
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Land Cover Validation

• Statistical Assessment Based on Site Data
• Cross-validation provides probability estimate
  for errors of omission/commission
• Two sets of site data
• DISCover Core/Confidence sitesRandom stratified
  sample based on DISCover Land Cover map (Loveland
  et al., EDC)
• Supplemental sites compiled at BUno explicit
  sampling design, but large N

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Validation Accuracy Assessment

• Classification Accuracy from Cross-Validation of
  Training Sites
• Hide 20 percent of training sites, classify with
  remaining 80 percent repeat five times for five
  unique sets of all sites
• Provides confusion matrix
• Not a stratified random sample, but a good
  within-class indication of accuracy

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Confusion Matrix

• Global Test Site Confusion MatrixProvisional
  Product

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Per-Pixel Confidence Output

• Per-pixel Confidence
• Based on statistical boosting theory
• Allows decision-tree classifier to estimate
  probability of classification associated with
  each possible class label
• Output for label with highest probability for
  each pixel

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Validation Other Datasets

• Comparison with Community Benchmark Datasets
• Global (e.g., DISCover, UMd from AVHRR)
• Comparison with independent maps derived from
  high resolution data, e.g.,
• Humid Tropics Landsat Pathfinder
• Forest Cover FAO Forest Resources Assessment
• Western Europe CORINE
• United States USGS/EPA MLRC
• United States California Timber Maps (McIver and
  Woodcock)

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Validation Comparisons

• Collaborative Comparisons
• BigFoot sites
• MODLand Test Sites

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BigFoot Results
Reprojection of BigFoot UTM maps to ISIN
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Conclusions

• MODIS Land Cover Product
• Draws on AVHRR heritage
• Utilizes improved data and techniques
• Top-down, globally-consistent approach
• Validation plan emphasizes multiple approaches to
  build confidence
• Validated product to be released about 15 April
  2002 based on 2001 data