http://nrm.salrm.uaf.edu/~dverbyla/nrm338/http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11 12 4 5 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 12 13 14 6 7 8 9 10 11 12 13 14 15 7 8 9 10 11 12 13 14 15 16 8 9 10 11 12 13 14 15 16 17 9 10 11 12 13 14 15 16 17 18http://nrm.salrm.uaf.edu/~dverbyla/nrm338/http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11 12 4 5 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 12 13 14 6 7 8 9 10 11 12 13 14 15 7 8 9 10 11 12 13 14 15 16 8 9 10 11 12 13 14 15 16 17 9 10 11 12 13 14 15 16 17 18http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11 12 4 5 6 7 8 9 10 11 12 13 5 6 7 8 9 10 11 12 13 14 6 7 8 9 10 11 12 13 14 15 7 8 9 10 11 12 13 14 15 16 8 9 10 11 12 13 14 15 16 17 9 10 11 12 13 14 15 16 17 18 Max Minhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Stretched value = (pixel value – min) / (max – min ) * 255 = (11 – 0) / (18 – 0 ) * 255 = 156http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Min = mean – 4, max = mean + 4 Stretched value = (pixel value – min) / (max – min ) * 255 = (8 – 5) / (13– 5 ) * 255 = 95.6 = 96http://nrm.salrm.uaf.edu/~dverbyla/nrm338/http://nrm.salrm.uaf.edu/~dverbyla/nrm338/http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Color Raster • Additive primary colors: red, green, blue lights • Subtractive primary colors cyan, magenta, yellow pigmentshttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Additive Primary Colorshttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 255 0 0 0 255 0 0 0 255 255 255 0 0 255 255 255 0 255 100 100 100 200 200 100 100 100 0http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 255 0 0 0 255 0 0 0 255 255 255 0 0 255 255 255 0 255 100 100 100 200 200 100 100 100 0http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Landsat Images • Bands 1-3 blue, green, red spectral regions • Bands 4-7 invisible spectral regions • Band 4 near infrared (NIR) • Bands 5, 7 middle or SWIR infrared • Band 6 thermal infraredhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Landsat Rasters • Free to download as Geotiff Rasters • UTM coordinates, NAD83 • Bands 1-5,7--- 30 meter pixels • Band6 thermal--- 60 m pixels • Band 8 panchromatic--- 15m pixelshttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Color Image Displayhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Color Infrared Image Displayhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ False Color Displayhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Supervised Classification Sample polygons from known cover types Spectral statistics from known cover type Predict cover type of each raster pixelhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Training Polygons Mean Standard Deviation Unburned 20 5 Burned 30 5http://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Maximum Likelihood Classifier • Assumes bell-shaped likelihood, peaking at meanshttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 10 11 12 17 18 27 33 31 32 10 12 13 15 19 21 32 30 30 11 12 13 14 19 20 31 28 31 12 13 14 17 19 27 29 29 32 14 16 16 18 20 27 28 31 30 1 1 1 1 1 2 2 2 2 1 1 1 1 1 1 2 2 2 1 1 1 1 1 1 2 2 2 1 1 1 1 1 2 2 2 2 1 1 1 1 1 2 2 2 2 Classifier 1= predicted unburned 2=predicted burnedhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ 10 11 12 17 18 27 33 31 32 10 12 13 15 19 21 32 30 30 11 12 13 14 19 20 31 28 31 12 13 14 17 19 27 29 29 32 14 16 16 18 20 27 28 31 30 1 1 1 1 1 2 2 2 2 1 1 1 1 1 1 2 2 2 1 1 1 1 1 1 2 2 2 1 1 1 1 1 2 2 2 2 1 1 1 1 1 2 2 2 2 Classifier unburned burnedhttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Error Matrix • Comparing “ground truth” or reference data with classified raster or predictionshttp://nrm.salrm.uaf.edu/~dverbyla/nrm338/ Overall accuracy = correct predictions/ total predictions = (48 + 40) / 110 Sea Ice accuracy = 40/50 = 80 % or 40/52 =