R ELATEDNESS AND SCALE DEPENDENCY IN VERY HIGH RESOLUTION DIGITAL - PowerPoint PPT Presentation

R ELATEDNESS AND SCALE DEPENDENCY IN VERY HIGH RESOLUTION DIGITAL ELEVATION MODELS DERIVATIVES Kevin Leempoel, Stéphane Joost Labo�atoi�e des Syst��es d’I�fo��atio� G�og�aphi�ue ( LASIG ), EPFL M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 1

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives • Landscape genetics Association between genetic markers and environmental variables. Limited use and exploitation of DEMs • In mountainous areas, patterns of environmental conditions are driven by relief. • Exploiting correlation between difficult -to- observe causal variables and easily observed non-causal variables. M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 2

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives • For regional studies on adaptation, climatic variables at 25m are enough. • At our study site, our plant are showing local adaptation (smaller extent) • Plants on the ridge, how fine does the resolution has to be in order to model correctly the environment? M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 3

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Objectives • Perform correlations between variables computed at different resolutions • Assess accuracy of a freely available model (ASTER GDEM) for the production of variables • Same for a VHR image-matching model (Sensefly/R- pod) • Analyze correlations with climatic variables • Assess the usefullness of VHR DEMs derived variables to discover or confirm genes functions M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 4

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives • Study Area at « Les Rochers-de-Naye » • Plant : Biscutella Laevigata • 297 markers sequenced for 178 individuals (will be available for ≈ 300 individuals) Biscutella laevigata Les Rochers-de-Naye M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 5

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Models HELI025 Spatial 0.25m resolution Accuracy <0.1m LIDAR Comment equiped on an helicopter Models Rpod05 Spatial 0.5m resolution ≈1m Accuracy Image matching, Comment taken from a drone M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 6

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Models ST2 Spatial 2m resolution ± 0.5m Accuracy LIDAR, Only available Comment under 2000 meters Models ST25 Spatial 25m resolution ± 2m Accuracy Interpolated Comment from contour lines M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 7

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Models ASTER31 Spatial 1 arcsec (≈30m) resolution ± 15m (v.2) Accuracy Missing data for regions under constant Comment cloud cover Important artefacts http://www2.jpl.nasa.gov/srtm/instr.htm; http://www.jspacesystems.or.jp/ersdac/GDEM/E/2.html M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 8

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives • Variables computed in SAGA GIS • free GIS software made for geoscientists • Coded in C++, provided with a GUI • Helped by RSAGA package in R M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 9

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Variables Computed from DEMs Terrain attributes (Slope, Orientation, Curvature) Morphometry indices (Protection index, skyview factor, Topographic Ruggedness Index) M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 10

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Variables Computed from DEMs Insolation variables (direct, total, duration) Hydrology variables (catchment area, wetness index, stream power index) M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 11

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Climatic variables (Zimmerman & Kienast, 1999) 18 selected ETPT : Daily average of Srad: Daily average of global potential evapotranspiration per year shortwave radiation per year M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 12

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Sampling schemes M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 13

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Statistical tools • Correlation between variables assessed with Spearman's rank correlation coefficient • Bonferroni correction applied • Association models computed in SAM (spatial analysis method) (Joost et al , 2007) Based on spatial coincidence , can investigate the causes of selection . M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 14

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Corr coef Heli025 Rpod05 ST2 ST25 ASTER31 Heli025 1.000 1.000 1.000 0.993 0.974 279 points Rpod05 1.000 1.000 1.000 0.993 0.975 Altitude ST2 1.000 1.000 1.000 0.993 0.975 ST25 0.993 0.993 0.993 1.000 0.974 ASTER31 0.974 0.975 0.975 0.974 1.000 Corr coef Heli025 Rpod05 ST2 ST25 ASTER31 Heli025 1.00 0.43 0.81 0.49 Rpod05 0.43 1.00 0.41 0.35 Slope ST2 0.81 0.41 1.00 0.52 ST25 0.49 0.35 0.52 1.00 0.31 ASTER31 0.31 1.00 Corr coef Heli025 Rpod05 ST2 ST25 ASTER31 Heli025 1.00 0.47 0.88 0.64 0.31 Rpod05 0.47 1.00 0.53 0.45 Cos Orientation ST2 0.88 0.53 1.00 0.72 0.39 ST25 0.64 0.45 0.72 1.00 0.57 ASTER31 0.31 0.39 0.57 1.00 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 15

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Total insolation (21/06) Corr 279 points Heli025 Rpod05 ST2 ST25 ASTER31 coef Heli025 0.99 0.53 0.80 0.47 Rpod05 0.52 0.99 0.48 0.37 Direct insolation ST2 0.80 0.50 0.99 0.55 Correlations between (21/6) ST25 0.50 0.40 0.57 0.99 0.32 insolation variables ASTER31 0.99 Corr coef ST25 srad3 Total Insolation 3a 0.726 Total Insolation 3b 0.745 Exploiting different options for the Total Insolation �c ��” 0.729 computation of insolation variables Total Insolation 3b ��” 0.742 Total Insolation 3b ��” 1h 0.742 Total Insolation 3b ��” 1h 0.745 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 16

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Sampling locations Correlations and summary statistics of Altitude Altitude of sampling DGPS Heli025 Rpod05 ST2 ST25 ASTER31 locations (511points) DGPS 1.000 1.000 0.973 0.951 0.889 0.955 Heli025 1.000 1.000 0.973 0.951 0.889 0.955 Rpod05 0.973 0.973 1.000 0.966 0.863 0.931 ST2 0.951 0.951 0.966 1.000 0.824 0.933 ST25 0.889 0.889 0.863 0.824 1.000 0.904 ASTER31 0.955 0.955 0.931 0.933 0.904 1.000 DGPS Heli025 Rpod05 ST2 ST25 ASTER31 mean 1964.8 1965.0 1964.3 1962.2 1960.7 1961.3 sd 38.09 38.13 38.09 38.34 37.10 36.55 min 1866.7 1867.0 1866.1 1866.6 1864.8 1868.0 max 2031.4 2031.6 2031.8 2031.3 2023.4 2016.9 range 164.7 164.7 165.6 164.7 158.6 148.8 # unique values 470 451 399 176 39 30 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 17

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Sampling locations Corr Heli025 Rpod05 ST2 ST25 ASTER31 coef Heli025 1.00 0.24 -0.26 Rpod05 0.24 1.00 Slope ST2 1.00 ST25 1.00 0.23 ASTER31 -0.26 0.23 1.00 Corr Heli025 Rpod05 ST2 ST25 ASTER31 coef Heli025 1.00 0.54 0.28 Rpod05 0.54 1.00 0.24 Cos Orientation ST2 0.28 0.24 1.00 0.24 ST25 0.24 1.00 -0.42 ASTER31 -0.42 1.00 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 18

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Sampling Sample of slope values from Heli025 locations Sample of slope values from ST2 Sample of slope values from Rpod05 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 19

Introduction / Goals / Materials&Methods / Results / Conclusions / Perspectives Slope from Heli025 and ST2m Orientation of Heli025 and Rpod05 M ULTI - RESOLUTION VARIABLES & L ANDSCAPE GENETICS – L EEMPOEL K. – OGRS – 26 O CTOBER 2012 20