Detecting Landscape Changes in High Latitude Environments Using Landsat Trend Analysis: 2. Classification

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1 1 Detecting Landscape Changes in High Latitude Environments Using Landsat Trend Analysis: 2. Classification Ian Olthof and Robert H. Fraser Canada Centre for Mapping and Earth Observation Natural Resources Canada 560 Rochester, Ottawa ON K1A OE4

2 Cumulative Impacts Monitoring Program (CIMP) 2 Supports monitoring in the NWT incorporating scientific and traditional knowledge Fill information gaps, report on the state of the NWT environment and cumulative impacts of water and land uses Collect and disseminate environmental information to Northerners, decisionmakers and industry

3 3 Arctic monitoring using EO Landsat-based Historical archive Appropriate scale Pouliot et al., 2009 Map dynamic change processes using Landsat image-stack and temporal profile matching Myneni et al. (1997) mapped Arctic greening from AVHRR image-stack Regeneration, succession, greening, erosion, deposition

4 4 Landsat image time-series stack USGS Glovis L1T, Top-Of-Atmosphere Tasseled Cap Brightness Greenness Wetness

correla6on - Regression coefficients and DT - linear -

5 5 Temporal profile matching Classify temporal profile : Using : Min. distance - Euclidean - Frechet Shape - Max. correla6on - Regression coefficients and DT - linear - polynomial Against reference database : Deposi6on Greening etc Erosion

6 6 Temporal alignment Profile distance is affected by temporal alignment - Euclidean distance more so than Frechet Profile shape is less sensi6ve to alignment - cross- correla6on - regression coefficients Solu6on 1 : Reference data that includes a range of disturbance 6mings - synthe6c reference data generated by applying temporal offsets Solu6on 2 : Methods that align trajectories prior to classifica6on - can be computa6onally intensive 6me

7 Study area 7

8 Reference data No external reference dataset exists with the spatial extent, temporal

by Indian and Northern Affairs Canada, photos are from August 2004, 1:3000 scale, ~1 m

Visual interpretation of 1985 and 2011 image pairs used to generate image stacks NWT Department

and ETM+ imagery Fire History of NWT National Air Photo Library photographs Ecological Land

Oblique air photos from helicopter Google Earth National Hydro Network Peel Plateau thaw slumps

drained lakes, seismic lines Footprint and type of municipal development All All Post-1965

fires, thaw slump progression NWT Department of Environment and Natural Resources, >60,000

All 208 vertical air photos pairs from 1980 and 2013, ~2 4 cm effective resolution, 14 flight

Tuk, August 2013, and around Yellowknife, August 2011 and June 2012.

8 8 Reference data No external reference dataset exists with the spatial extent, temporal frequency and thematic detail to create a truly independent and consistent record Cohen et al., Data Set Description Mackenzie Valley Orthophotos (MVAP) NWT Community Orthophotos Contracted by Indian and Northern Affairs Canada, photos are from August 2004, 1:3000 scale, ~1 m resolution Acquired by NWT Department of Municipal and Community Affairs in , 5 cm resolution SPOT 4&5 imagery processed by NWT Centre for Geomatics, pan-fused 10 m resolution Visual interpretation of 1985 and 2011 image pairs used to generate image stacks NWT Department of Environment and Natural Resources, burned area polygons SPOT Imagery Landsat TM and ETM+ imagery Fire History of NWT National Air Photo Library photographs Ecological Land Classification (ELC) oblique air photos Vertical color and color-infrared air photo pairs Oblique air photos from helicopter Google Earth National Hydro Network Peel Plateau thaw slumps NWT Seismic Lines NWT Spatial Data Warehouse Types of Change Features Corroborated Slumps, drained lakes, seismic lines Footprint and type of municipal development All All Post-1965 forest fires Panchromatic photographs , scales of 1:5000+ Pre-1965 forest and tundra fires, thaw slump progression NWT Department of Environment and Natural Resources, >60,000 oblique aerial photographs from 2005 to All 208 vertical air photos pairs from 1980 and 2013, ~2 4 cm effective resolution, 14 flight lines over Tuktoyaktuk Peninsula [16] Photos taken around Ft McPherson and between Inuvik and Tuk, August 2013, and around Yellowknife, August 2011 and June Areas containing high resolution (<4 m) imagery Lake perimeters and stream networks at 1:50,000 scale 212 digitized slumps [17] Historical seismic line GIS database from National Energy Board Geospatial Portal containing numerous NWT spatial datasets Shrub proliferation All All Draining lakes, thaw slumps Retrogressive thaw slumps Seismic line disturbances Mineral, oil, and gas developments

9 9 Classification legend #Polygons Context Process Disturbance or Change Class (Region 2) Recent forest fire (based on NWT fire 2. regeneration 86 history database) Burnt area 3. succession Pre-1965 forest fires 4 4. succession Pre-1965 tundra fires 27 River/stream slumps Lakes Streams 6. erosion Active and wet portion of slump 4 2. regeneration Late regeneration (later vegetation growth) 1 6. erosion Active slump 4 6. erosion Eroded lake shorelines 9 7. deposition/drainage Recently drained tundra lake 8 2. regeneration Older portion of slump emergent vegetation colonization Drained lakes with vegetation growth erosion Conversion of sandbar to stream 3 7. deposition/drainage New stream and river sandbars 3 1. emergent vegetation colonization Conversion of stream bed to vegetation vegetation removal Conversion of vegetation to exposed stream bed 4 Coastal 6. erosion Eroded coastal shorelines 2 Human developments Mackenzie delta Tundra 5. vegetation removal Development (removal of vegetation) 7 8. no change Developed erosion Delta erosion deposition/drainage Delta deposition tundra greening (shrubification) Shrub proliferation 7 Stable 8. no change Non-disturbed area 22

10 10 Method evaluation- 21 change classes Profile Matching Region 2 Region 1 Region 3 Maximum cross-correlation Minimum Euclidean distance Minimum Frechet distance See5 decision tree classification of regression coefficients Regression Region 2 Region 1 Region 3 Linear least-squares Linear robust (Theil-Sen) Secord-order polynomial Third-order polynomial

11 Thiel-Sen linear regression coefficients classified using See5 21 change classes 11 Overall classification accuracy obtained using 100 cross-validation iterations and different percentages of training and test polygons Training Test Overall Accuracy 50% 50% 81.6% 75% 25% 82.8% Sum of ranks of variable importance over 100 decision tree model iterations Coefficient Sum of Ranks TCB_slope 134 TCG_offset 236 TCG_slope 333 TCB_offset 401 TCW_offset 433 TCW_slope in order of variable importance

12 12 Final product merged to eight change processes

13 13 Canada Pan-Arctic

14 Conclusions Moving from mapping to change detection to a paradigm of mapping processes made possible by the availability of satellite image

'validation' in the strictest sense Change processes were best mapped using linear regression coefficients classified with See5 Decision Trees,

14 14 Conclusions Moving from mapping to change detection to a paradigm of mapping processes made possible by the availability of satellite image time-series, i.e. Landsat Validating Arctic change is more a case of 'corroboration' using available sources of data and evidence, rather than 'validation' in the strictest sense Change processes were best mapped using linear regression coefficients classified with See5 Decision Trees, which outperformed polynomial coefficients and distance and shape-based profile matching Additional work is needed to better deal with temporal mis-alignment

GIS compilation of coastline variability spanning 60 years in the Mackenzie Delta and Tuktoyaktuk in the Beaufort Sea

GEOLOGICAL SURVEY OF CANADA OPEN FILE 7685 GIS compilation of coastline variability spanning 60 years in the Mackenzie Delta and Tuktoyaktuk in the Beaufort Sea S. Hynes, S.M. Solomon, and D. Whalen 2014