Contents
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Development of a reference data base and validation concept for RS-based forest cover change products in Fiji Johannes Eberenz 1 , Johannes Reiche 1 , Samuela Lagataki², Akosita Lewai², Wolf Forstreuter³ 1) Wageningen University, The Netherlands; 2) Fiji Forestry Department (FFD); 3) SOPAC, South Pacific Counsel, Fiji
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Development of a reference data base and validation concept for RS-based forest cover change products in Fiji. - PowerPoint PPT Presentation
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Development of a reference data base and validation concept for RS-based forest cover change products in FijiJohannes Eberenz1, Johannes Reiche1, Samuela Lagataki², Akosita Lewai², Wolf Forstreuter³1) Wageningen University, The Netherlands; 2) Fiji Forestry Department (FFD); 3) SOPAC, South Pacific Counsel, Fiji
Contents
1. Introduction2. Forest cover change data3. Methodology
3.1 Database design3.2 Validation of RS-based products
4. Preliminary results5. Discussion
1 Introduction: Context
Study Program: ● Final year of MSc. Geo-Information
Science, Wageningen University, The Netherlands
● 2012 – 2014● Focus on RS
Internship exchange:● Internship at Fiji Forestry Department● October 2013 – March 2014● Supervised by Johannes Reiche ● Funded by GIZ
1 Introduction: Motivation
1 Introduction: Motivation
1 Introduction: Motivation and Goal
Reference data is crucial
For Fiji, different reference datasets are availbale
Problems:●Different formats●No common
interface●Unknown quality
Final Product:1. Database that
provides the framework to harmonize different reference datasets to assess forest change
2. Validation concept to use this DB for assessing RS-derived changes (bi-temporal, yearly changes)
1 Introduction: Concept of a Reference Database
Reference Database
Validation of RS-
products
Harvest & Planting maps
Existing databases
Digitized VHR
RS-based change products
IntegrationHarmonizing
Quality checks
2 Data: Different Change data sources
Logging, harvest and reforestation datasets
Selective logging of indigenous forests (FFD) National forest inventory (FFD) Harvest and replantation
(Fiji Pine Ltd., Fiji Hardwood Ltd.) Change areas derived from multi-temporal
very high resolution (VHR) datasets (e.g. WorldView)
All datasets require quality control for spatial and information consistency
2 Data: Example VHR images
KOMPSAR example (Detail)2008-09-03 2011-12-15
Panchromatic (1m)Multispectral (4m)
3.1 Methods: Database design
Specify requirementsExplore available data
Database designDefine interfaces
Demo implementation
3.1 Methods: Data Integration
Check input data quality of test areas (comparison to RS-products, jointly with FFD)
Develop a workflow for different data sources, vector and raster data
Demo implementation with selected datasets
Reference Database
Harvest & Planting maps
Digitized VHR
IntegrationHarmonizing
Quality checks
Johannes Eberenz
This is basically a preliminary result should be moved down?
3.2 Methods: Validation concept
Traditional methods:●Confusion matrix ●Accuracy measures:
Overall accuracy, Kappa, producers & users accuracy per class
Advanced methods:●Stratified estimation●Latent class analysis
Confusion
Matrix Change 2005
Change 2006 ...
No Change ∑i*
User Accuracy
Change 2005 n11 n12
n1
*
n11
/∑i*
Change 2006
...No
Change n21 n22n2
*
n22
/∑i*
∑*j n*1 n*2 NProd.
Accuray
n11
/∑*j
n22 /∑*j
∑diag/N
Reference Database
Validation of RS-
products
RS-based change products
3.2 Methods: Example Confusion Matrix
Confusion Matrix Change
2005Change
2006Change
2007No
Change ∑i*
User Acc.
Change 2005 3450 64 132 16 3662 0,942
Change 2006 531 1659 124 4 2318 0,716
Change 2007 17 979 3210 133 4339 0,740
No Change 7 27 469 5253 5756 0,913∑*j 4005 2729 3935 5406 13572
Prod. Accuray 0,861 0,608 0,816 0,972 0,844
3.1 Methods: Demo Implementation
Simple Schema (Single Table) Use available spatial data infrastructure:
● SOPAC GeoNode● Local solution at forestry department
Stepwise integration of available data● Different data sources ● Vector and raster data
Demonstrate use: ● Demo validations● Workshop
4 Prelimary Results: Demo Validation
Validation: confusion matrix & accuracy measures
RS-based forest cover change product:Deforestation from Landsat time series
Reference data:Logging year form Fiji-Pine
4 Prelimary Results: Demo Validation
RS-based forest cover change product:Change year from Landsat time series
Reference data:Logging year form Fiji-Pine
5 Discussion
Final Product:1. Database that provides the framework to
harmonize different reference datasets to assess forest change
2. Validation concept to use this DB for assessing RS-derived changes (bi-temporal, yearly changes)
Challenges:●Different data quality●Validation of selective logging●...?
