| the AVHRR NDVI data series analysis [message #46137] |
Sun, 30 October 2005 06:01 |
bing hu
Messages: 3
Registered: October 2005
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Junior Member |
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the 19 years AVHRR NDVI data have been combined one binary data, which
have three dimension,
1th dimension: longitude
2th dimension: latitude
3th dimension: the 36 periods ndvi value over 19years
ndvi=(1024,1024,684)
though analyzing the third dimension's data to determine the
beginning of the growing season(BGS) and the ending of the growing
season(EGS).thus ,we can determine the growing length during a total
year.(36 periods)
I'd have to find the maximum and minimum of pixel value during the 36
periods over the 684 images (684=19years*36period). Each 36 periods
have one maximum and two minimum.(from the ndvi curve,the first minimum
means the beginning of spring and the maximum means the summer,the
second minimum means the beginning of fall.)
Then I need to calculate the average of the maximum and minimum value
over the 36 periods.
Finally, determining the index of the average over the 36 periods
through the 684 images.
How to do it?
I do not want to use loop.
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