Discussions around the different methodologies and consensus for a regional monitoring

Transcription

1 Discussions around the different methodologies and consensus for a regional monitoring Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

2 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

3 Dates It depends on the availability of images : 3rd period : As the first study was since 2000 to 2007,it could be interesting to produce this study around Thus, we will can calculate regional dynamics on the Guiana Shield -> Priority for 2014 images, then 2013 images, then 2012 images (additionnal SPOT 4 images)

4 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

5 Data sources -> To detect impacted surfaces (from gold mining/infrastructures) * Focus SPOT 5 as best resolved (10m in colors) ; then SPOT 4 (20m in colours same bands). ->Level 2A -> Focus on <20% clouds then <40%, then <60%, no more 60 %. -> Angle 30 -> The operability depends on the repartition and density on the clouds. -> Haze is a problem but not everytime ; it depends on the density of haze. -> Quickview * Landsat 8 (30m) to complete if there are too many clouds * SPOT 6 (6m in colors) : 1-2 images / country for validation -> To detect impacted river network : SRTM 30

6 Data sources

7 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

8 Georeferency and projections systems * The area study is cover by 3 projection systems :WGS 84 UTM N. * The geographic referential of the project is the last shape of deforestation (existing in the 3 projections systems : WGS84 UTM ) -> if there is a shift between satellite image and the shape, the reference is the shape. -> Each technician will digitalyse in his country / satellite image projection and then ONF-G assemble in one shapefile : WGS 84 EPSG

9 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

10 Clouds * In the last study: If there are clouds everywhere -> no data * If there are clouds in over a gold mining site of 2007 on all SPOT images : -> Proposal : Landsat image -> If there are clouds on the landsat image -> no update -> remark in the attribut data (cloud). * How to do with the area with clouds? -> Proposal : mosaic / percentage of cloud cover

11 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

12 LANDSAT Impacted area

13 Impacted linear

14 Differents types of infrastructures : On a satellite image

15 Objects to numerize * For gold mining activities : -> it s an update -> we have to follow the last methodology: 2 objets : -> Mining sites (alluvial or primary) -> Impacted network * For infrastructures -> it s new -> we have to create the methodology but the ToR says : -> Roads -> Settlements -> Roads : -> How wide? (in F.G > 50 m for roads ans associated surfaces) -> Proposal : 50 m -> Settlements : -> Wich type of settlements? Towns? Villages? Isolated habitat? Industrial area? -> With SPOT 5 it s difficult to disciminate other that towns and roads except with additionnal data like land use data) -> Proposal : 1 Shape with predefined list with choices : road / settlement (no agriculture). * Roads and settlements in mining site? Classified in Gold mining or settlements? -> Proposal : classified in infrastructures to not have confusion.

16 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

17 Processing 1- Automatic or manual? With the return of experience of the first study, the automatic procedure is not very interesting. Too much time is lost to clean artifacts (especially clouds) and then check and rescan the impacted areas. -> Proposal : Manual photo-interpretation and update from the last shapes : deforested surface / impacted network. 2- What is the Minimum Map Unit? Guyana Countries Minimum Map Unit 1 ha Rapid Eye (5m) Suriname 1 ha (Landsat 30 m) Amapa 1 ha (Landsat 30 m) French Guiana 0.5 ha (SPOT 10m) -> Proposal : Minimum Map Unit : 0.5 ha

18 Processing 3- Scale of numerization? -> Scale of numerization : 1/5000 in the last study -> It s better to conserve the same level of details. -> The data have the same resolution -> Proposal : 1/ How do digitalize objects? -> "Real" False colors display : SWIR, Green, Red -> Infrared false colors display : NIR, Red, Green -> possibility to do contrast and histogramm adjustements -> closer limits of deforestation

19 5 Misclassified or not classified object in the previous study? -> Errors can be corrected retrospectively -> Objects not classified in the previous study can be classified for this update. 6 Help for the photo-interpretation 2 options : - each country with just satllite images and previous shape - each country with his local shapes, even if it could begin a bit incoherent between countries -> Proposal : - each country with his local shapes 7 Wich type of ancillary data? -> mining activities -> shape of land use -> shape of geology -> mining concessions -> local geographic referential -> fields data -> protected areas Processing

20 Discussions around the different methodologies and consensus for a regional monitoring 1- Dates 2- Data sources 3- Georeferency and projection system 4- Clouds 5- Objects to numerize 6- Processing 7- Validation Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER

21 Validation Internal control -> Proposal : some areas can be verified by the other operator -> SPOT 6 control * Regional control -> Delivery of initermediate processing results at the end of february -> 1 ONF technician is on 1 mission / country in march * External control -> ONFI

22 Discussions around the different methodologies and consensus for a regional monitoring Update of the WWF study - First training session Novembre 2014 Cayenne Gaëlle VERGER