wiki:exercise8

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 wiki:exercise8 [2017/12/05 22:53] wiki:exercise8 [2020/07/17 06:39] (current) Line 1: Line 1: + ====== Exercise 8: Create yearly MODIS composite ====== + In this exercise the following tools will be used: + * pktools: pkmosaic + * bash: for loop, echo + + In this exercise we will learn how to create a maximum value composit image when a number of images are available with overlap. + + The MODIS images at 500 m have 7 spectral bands and an additional two bands for the cloud mask and a count value. ​ + + The cloud mask is defined as: 0 (most likely cloudy), 1 (probably cloudy), 2 (probably cloud free) and 3 (most likely cloud free). + + The count value represents the number of valid images that were used for the composit. see how to create a yearly MODIS composite at 500 m for 2010. + + Select cloud free pixels only (cloud value > 2) and use a compositing rule that selects the maximum NDVI value (rule=1). + + __look at the help information how to use pkmosaic__ + + + pkmosaic -h + ​ + + + The MODIS bands at 500 m:\\ + band 1: red\\ + band 2: nir\\ + band 3: blue\\ + band 4: green\\ + band 5: nir\\ + band 6: swir\\ + band 7: mir\\ + band 8: cloud mask (3 is cloud free)\\ + band 9: number of days used for monthly composit\\ + ​ + + ​Do not forget that pktools start counting from 0​ + + + pkmosaic \$(for file in \${MODIS500DIR}/​2010*-MODIS500_CW.tif;​do echo " -i " \$file;done) -o \${OUTPUTDIR}/​2010-MODIS500_CW.tif --rband 0 --rband 1 -m 1 --validBand 7 -min 2 +