GLC 2000 Project Results from Southeast Asia Stibig HJ', Upik R'W', Beuchle R', Mubareka, S', Hildan

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GLC 2000 ProjectResults from Southeast Asia
Stibig H-J., Upik R.W., Beuchle R., Mubareka,
S., Hildanus, Giri C.
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Southeast Asia
Continental Southeast Asia Monsoon Climate Wet
Season May November Dry Season December
April Variable conidtions over Vietnam Mix of
evergreen and seasonal / dry vegetation Reasonably
cloud-free images end Dec middle of March
Insular Southeast Asia Moist tropical climate
all year short less humid periods
(hemisphere, spec. island, spec. loc.) Evergreen
vegetation No cloud haze free images all year
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Example for good quality 10 - day mosaic
February 1999
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Example Typical 10 - day mosaic from May 2000
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Main challenges for mosaic generation and mapping

• Continental Southeast Asia
• obtain good differentiation between seasonal and
  evergreen vegetation formations
• to cope with the mixed pattern of cropland,
  shrub, re-growth, forest (active and abandoned
  shifting cultivation)
• get sufficient haze and cloud free data over
  Vietnam
• Insular Southeast Asia
• cope with persistent haze and cloud cover

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Test with S1 Data from the year 2000 (S. Mubareka)

• Continental SE-Asia S1-images for Jan-Feb 2000
• Insular SE-Asia S1-Images full year 2000

• SWIR line error mask
• Cloud mask threshold blue lt 720 SWIR lt 320
• Filter for angle Flt45º and hot spots (F,f)
• Water mask

• Mosaic Generation
• Selecting from the top15 percent of NDVI values
• Minimum value in the red channel

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Test with S1 data from 2000 (S. Mubareka)
Contin. Se-Asia Jan-Feb 2000
Insular SE-Asia Year 2000
acceptable result more images to be included -
remaining holes and mosaic effects - separation
evergreen / deciduous limited - low quality over
parts of Vietnam
insufficient for removal of cloud haze
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Mosaic generation from S10 data year 1998 to
early 2000

• Cont. SE-Asia S10 composites of dry seasons 1999
  2000 (Jan-Mar)
• Ins. SE-Asia S10 composites Mar-Nov 1998-1999,
  Jan-Mar 2000

• Threshold for SWIR line errors (gt5 in the SWIR
  band)
• Cloud-haze threshold ( lt10 in the blue band)
• Cloud-shadow masks by unsupervised classification

• Mosaic Generation in 2 Steps
• Monthly Mosaics Pixel selection by minimum in
  SWIR
• (good contrast for forest, reduction of
  atmospheric angular effects, line errors)
• Annual Mosaics Pixel selection by minimum in NIR
• (further enhancement of contrast between
  evergreen and deciduous vegetation)

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Mosaic detail Continental SE-Asia
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Mosaic detail Insular SE-Asia
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Mapping Approach for SE-Asia

• Unsupervised clustering and maximum likelihood
  classification
• 70 clusters cont. SEA, 60 clusters ins SEA
• Cluster labeling and grouping to land cover
  classes
• supported by interpretation from available TM
  scenes, maps, field records
• Specific for continental SE-Asia
• Splitting up of clusters for different
  bioclimatic zones
• Correction of errors for selected AOIs
• Specific for Ins. SE-Asia
• mapping of formerly burnt areas and of irrigated
  cropland supported by a rough stratification of
  vegetation and non-vegetation from the S1 Mosaic

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GLC2000 Map Continental SE-Asia
Evergreen forest
Deciduous forest woodland
Shifting cultivation mosaics
Cropland inundated
Cropland
Evergreen forest
Deciduous forest woodland
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GLC2000 Map Insular SE-Asia
Cropland annual
Shrub re-growth, burnt 1997/98
Evergreen forest
Mix of thickets, shrubs, perennial cropland (oil
palm, rubber plantations)
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Legend SE-Asia

• transitions to shrubs
• differentiation closed open not possible

• incl. degraded forests, shrub cover

Natural Vegetation / Cropland
shifting cultivation

• other land cover components partly unknown

• includes cropland mosaics

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Map comparison for the Lower Mekong Basin
MRC Map from interpretation of 1997 TM Scenes
GLC2000
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Forest Cover Map of Peninsular Malaysia
National Forest Inventory Map 92
GLC2000 Map
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The End