I am conducting a trend analysis of SST from AVHRR data. My cloud flagged pixels are set to zero. I want to remove these pixels entirely from the analysis as zero could be a legitimate sea surface temperature. I have 1456 images per dataset so individual masking is not feasible. I understand Idrisi does not have a No Data option, but I am sure others must have had a similar problem. Do you have a recommendation?
Thank you very much,
Michelle Howard
University of Idaho, Dept. of Geography
Michelle,
You will need to use the mask option on the Linear Trend panel. But this mask needs to be a Boolean image containing every cloud pixel throughout the series. I assume you have for each month an image that has clouds pixels that do not have the value 0. Otherwise, how are you determining which pixels are clouds? If you have these, you will need to make a composite and use the composite result as a mask. This can be easily done using Macro Modeler.
If by making this composite it essentially masks your entire study area, you should try spatially interpolating SST in these cloud pixels. This can be done using the Missing Data Interpolation panel in ETM. It was specifically designed for such cases.
Let me know if I am misunderstanding.
James Toledano
Clark Labs
Hello
i have dataset comprising MODIS MCD43A4 imagery. calculate NDVI using these product, but at somewhere of my study area have pixles which contain no data. I will appteciate if help me.I do Filter/Mode and another function but get nothing.
best,
Naghmeh Gholami
Hi Naghmeh,
I believe the same would apply, explore the Missing Data Interpolation panel in ETM. It is designed to help with no data issues, such as cloud contamination.
James Toledano
Clark Labs
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