Methods of Validating Maps of Deforestation and Selective Logging Carlos Souza Jr. [email protected]Instituto do Homem e Meio Ambiente da Amazônia—Imazon Caixa Postal 5101, Belém, PA, Brasil CEP 66613-397 Department of Geography – University of California Santa Barbara, California 93106, USA [becky,matzke,carlos,mclark,numata,dar]@geog.ucsb.edu
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Methods of Validating Maps of Deforestation and Selective Logging Carlos Souza Jr. [email protected] Instituto do Homem e Meio Ambiente da Amazônia—Imazon.
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Methods of Validating Maps of Deforestation and Selective Logging
to propose protocols for ground-based accuracy assessments of remotely sensed estimates of deforestation and selective logged forests.
to address means of establishing error bars and accuracy estimates pertaining to deforestation and selective logging products.
Protocol for Accuracy Assessment of RS Products
Response DesignProtocol
Sampling DesignProtocol
Estimation andAnalysis Protocol
AccuracyAssessment
Stephen V. StehmanStephen V. StehmanRaymond L. CzaplewskiRaymond L. Czaplewski
RSE, 1998. 64:331-344RSE, 1998. 64:331-344
Sampling Protocol
Sample unit is a location (point) or
an area (pixel or polygon) used to assess the accuracy of a map.
links the map and the reference data. Pixel sampling
unit
Reference data (Ikonos)
Response DesignProtocol
Sampling DesignProtocol
Estimation andAnalysis Protocol
AccuracyAssessment
Stephen V. StehmanStephen V. StehmanRaymond L. CzaplewskiRaymond L. Czaplewski
RSE, 1998. 64:331-344RSE, 1998. 64:331-344
Sampling Protocol
Sampling method Requires an unbiased sample
Simple random Stratified random Cluster
Primary (psu) Secondary (ssu)
Polygon
psu
ssu
5x5 pixelblock
ssu
psu
““A scientifically defensible accuracy A scientifically defensible accuracy assessment requires a assessment requires a probability sampling”probability sampling”
Stephen V. StehmanStephen V. StehmanRaymond L. CzaplewskiRaymond L. Czaplewski
RSE, 1998. 64:331-344RSE, 1998. 64:331-344
Response DesignProtocol
Sampling DesignProtocol
Estimation andAnalysis Protocol
AccuracyAssessment
Response Design
It is a classification scheme applied to the sampling unit. Labeling protocol
Assigns a land-cover classification to the sampling unit based on the evaluation protocol:
Land cover proportion Predominant land-cover Centroid Multiple land cover classification Fuzzy classification
Evaluation:• 50% vegetation• 40% bare soil• 10% shrubs
Labeling:• Pasture
Evaluation:• pixel centerLabeling:
• Forest
Stephen V. StehmanStephen V. StehmanRaymond L. CzaplewskiRaymond L. Czaplewski
RSE, 1998. 64:331-344RSE, 1998. 64:331-344
Response DesignProtocol
Sampling DesignProtocol
Estimation andAnalysis Protocol
AccuracyAssessment
Reference Data
D – DecidiousC – ConiferAG – AgricultureSB - Shrub
Stephen V. StehmanStephen V. StehmanRaymond L. CzaplewskiRaymond L. Czaplewski
RSE, 1998. 64:331-344RSE, 1998. 64:331-344
Response DesignProtocol
Sampling DesignProtocol
Estimation andAnalysis Protocol
AccuracyAssessment
Estimation andAnalysis
Problems with the Standard Protocol
Study Area
Sampling Design
Flight-line randomly sampled by time-code Cluster samples centered on flight-line Reference sample unit = 30 m x 30 m area Five reference samples recorded per mosaic
Evaluation Protocol: Class Definitions Primary forest Pasture trees >20 m height herbaceous contiguous canopy shrubs < 2 m Second-growth forest annual crops shrubs > 2 m Urban/soil trees < 20 m human structures perennial crops roads Water bare soil