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USGS/EROS Data Center Global Land Cover Project – Experiences and Research Interests. GLC2000-JRC March 2001. The USGS/IGBP Global Land Cover Database. USGS/IGBP Global Land Cover Database Strategy. Classification Methods. Flexible land cover database
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USGS/EROS Data Center Global Land Cover Project – Experiences and Research Interests GLC2000-JRC March 2001
Classification Methods • Flexible land cover database • Unsupervised multi-temporal classification of 1992-1993 AVHRR NDVI data • Classification implemented on a continent by continent basis • Team interpretation to encourage consistency • External peer review of draft results • Validated IGBP land cover layer
Continents to World – Combine Maps • Set rules for top and middle level classification systems • Describe land cover, vegetation seasonality, structure, and leave longevity consistently • Hold frequent project meetings to review consistency • Accuracy measured separately for each mapping area
EROS Data Center FRA2000 50% FOREST 100% AG 100% FOREST BRIGHTMODEL Channel 2 (NIR) DARKMODEL AVHRR Channel 1 (Visible) Global Forest Cover Mapping Canopy Density Model
EDC FRA2000 Project:— Estimating density of forest canopy cover …
A New Global Forest Cover MapImproved USGS global land cover database
Sampling-based field data Current and Future R&D Interests • Continue global land cover database research using new coarse/moderate resolution sensors • Test new techniques/algorithms • Integrate satellite imagery with sampling-based field data • Focus on attributes, themes that are useful for both science and land management
Land Cover Techniques at EDC • Unsupervised classification • Decision-tree models • Spectral mixture analysis • Experimental: Co-kriging, KNN, NN • Continued emphasis on database strategy and its improvement • Stratification before and after clustering
0 100% Example of Tree Canopy Density
Sample1: U1, V1 at (x1, y1) Calculate U0 at (x0, y0) Sample2: U2, V2 at (x2, y2) Sample3: V3 at (x3, y3) Spatial Modeling Techniques for Satellite Imagery-Field Data Integration • Spatial models such as KNN, Co-kriging are nonparametric spatial statistics • Potential tool for extending field measurements to image data/maps • Mapping vegetation structure measured on permanent plots =
Key Experimental Vegetation Type and Structure Variables • Biomass • Net primary productivity • Canopy density • Canopy height • Age • Size class • DBH • Vegetation species, types, associations
Summary • EDC is committed to continuing its global land cover R&D • Working with partners is important for USGS