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Institut für Vermessung, Fernerkundung und Landinformation
Operational smoothing of MODIS NDVI time series at BOKU
for EURODEER
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Institut für Vermessung, Fernerkundung und Landinformation
EURODEER Study Areas & BOKU MODIS Tiles
Institut für Vermessung, Fernerkundung und Landinformation
EURODEER MODIS Tiles – Tile naming I
Institut für Vermessung, Fernerkundung und Landinformation
EURODEER MODIS Tiles – Tile naming II
Institut für Vermessung, Fernerkundung und Landinformation
Principle of Whittaker smoother
Only one smoothing parameter
Interpolates automatically
No boundary effects
Input:
NDVI
composite day of year
data quality
Principle of Whittaker smoother
Offline filtering of entire time series
Institut für Vermessung, Fernerkundung und Landinformation
PNABCD
Processing dayN
2007050
INPUT:window_size = 25 * 7 = 175 days
7-day processing approach for Whittaker filter
For each EURDEER tile is delivered:./REFMIDw/MCD13Q1.A2006324.005.H19V04_h06v01.250m_7_days_NDVI.REFMIDw.tif./Dw/MCD13Q1.A2007022.005.H19V04_h06v01.250m_7_days_NDVI.Dw.tif
REFMID
Approach:• for every week all available MOD13Q1 and MYD13Q1 data
within the defined window of 175 days are used• filtering and interpolation/extrapolation at daily values• output of 7-day values: REFMIDw, Dw, Cw, Bw, Aw, Nw, Pw• Nw represents current Monday = newest product
D2007022
REFMID2007022
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Institut für Vermessung, Fernerkundung und Landinformation
Scaling of NDVI: 8 bit unsigned
𝑽𝑽𝑽𝑽 = 𝑽𝑽𝑽𝑽𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔 � 𝑫𝑫𝑫𝑫 + 𝑽𝑽𝑽𝑽𝒊𝒊𝒊𝒊𝒊𝒊𝒔𝒔𝒊𝒊𝒊𝒊𝒔𝒔𝒔𝒔𝒊𝒊
𝑫𝑫𝑫𝑫 = 𝑽𝑽𝑽𝑽 − 𝑽𝑽𝑽𝑽𝒊𝒊𝒊𝒊𝒊𝒊𝒔𝒔𝒊𝒊𝒊𝒊𝒔𝒔𝒔𝒔𝒊𝒊 / 𝑽𝑽𝑽𝑽𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔𝒔
NDVI 8 bit scalingDN flags 251 – ocean
252 – inlandwater255 – missing
DN valid range [0, 250]VIslope 0.0048VIintercept -0.2VI valid range [-0.2, 1.0]Data type uint8
DNdigital numbers [0, 250]
VIvegetation index[-0.2, 1.0]
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Institut für Vermessung, Fernerkundung und Landinformation
Delivery of Data
• delivery once on BOKU ftp:entire archive from 2003 to beginning of 2015172 tiles, products NDVI Dw, NDVI REFMIDw
• folder structure:one older for each tile containing the products Dw & REFMIDw
• weekly update as tar file on BOKU ftp
• see example for latest Monday (23.02.2015): ftp://ivfl-rio.boku.ac.at/EURODEER/update_2015054.tar
• every week tar file of previous week will be deleted
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